Diesel or petrol?

[Ferrer]

I can still remember when, not that long ago, diesel engines were considered smelly, dirty, noisy and underpowered lumps of metal. They were basically used in medium and heavy duty applications like buses, trucks or vans and the few cars that had them were slow and in general something to be avoided. Fast forward to 2009 and you can see them everywhere. Some cars, like the Citroën C6 or the Peugeot 407 Coupé are only sold with diesel engines.

Not only diesel cars seem to be the norm nowadays, but they have come a long way indeed from the early, and not so early, days. They have improved notably in the noise, vibrations and harshness department and they are ever increasing performance while reducing fuel consumption at the same time. Is there room for petrol engines at all these days?

I've always been a petrol defender. I've always thought that diesels were more suited to tractors and that anyone that bought a diesel was a bit greedy and not interested in cars. Certainly in some cases, like for instance people who do very high mileage, diesels do make a lot of sense and the savings are certainly noticeable. There are other cases though, in which people act like sheep. I have for instance never understood city cars with diesel engines under the bonnet. They are far more expensive than their petrol counterparts and the usually short distances driven by this sort of cars cannot compensate the price difference.

At the same time petrol engines have come a long way too. The latest technology includes direct fuel injection, turbocharging and downsizing. They have reduced fuel consumption and emissions greatly. Indisputably petrol engines are much more refined and smooth than diesels, even modern common rail units. You can try this by starting a petrol powered car and diesel powered car with the door open and then letting them idle. There's really no contest here. On the move the difference is much smaller, and here the advancements made by diesels are really clear. At high revs petrol beats diesel again, the noise made by petrol engines is much nicer.

And yet in some situations you just can't argue with diesels. In a recent 350km journey I did our BMW 118d recorded 7l/100km cruising at speeds between 160km/h and 180km/h about 90% of the trip. Even if you push hard you'll still struggle to get over 10l/100km. I have also had the opportunity recently to drive a brand new Lancia Delta T-Jet powered by a modern 1.4 litre turbocharged four cylinder engine. If you are careful with the throttle you can get relatively close to the BMW's figures, an average of 7 to 8L/100km is possible, but as soon as you start driving like an Italian numbers grow exponentially. 15L/100km aren't out of reach at all. So it doesn't look like you'll be buying a petrol for economy any time soon.

Despite all I still can't get to love diesels. I've driven one now for 1 and a half years and it's been brilliant, fast and frugal. It's not perfect though, there's still a bit of turbo lag and it isn't as refined as a good petrol motor but so far very good indeed. But I don't want it. Aside from the problems already mentioned, it makes me feel cold like if it was an appliance. When you are in your favourite mountain road enjoying the brilliant drive of your car the diesel engine is a big let down, it detracts much from the experience. I'm sure this is accentuated by the brilliant driving abilities of the little bimmer, and I wonder what would happen if the diesel was in the Delta and the petrol in the 1 series.

Then there are case in which a diesel engine simply has no place. These include cars with sporting pretensions like hot hatches and more than anywhere sportscars. Also some brands like Alfa Romeo or Jaguar, simply shouldn't offer a diesel at all, because those cars should be viewed as pure driver's cars and no driver's car should be saddled with a diesel engine because it's simply a sacrilege and there's no argument to be had here. Furthermore they have an heritage, expertise and aural pleasure that should never ignored. Of course for a bit of weekend fun petrol still reigns supreme.

However in the real world diesels do make a lot of sense, especially as soon as you are off the city and on to roads and motorways. The arguments for diesel are very strong and other than the romantic view it's difficult to make a case for an everyday petrol powered car. Heart says petrol, but head says diesel. What's it going to be?

[lightweight]

It all comes down to the way you use the car.

The truth is that from a financial point of view, the Diesel is superior to the Petrol engine because of its accessible power band and the better fuel economy for a given power figure.

Many argue for the emotional qualities of the petrol engine, like the higher revving character and the sound. True, but this realistically applies only to sports cars. If someone buys a Mondeo 3.0 V6, then he is wasting his petrol over a bad chassis.

Conclusion: 80% of the population's driving style is better suited to the Diesel, but for some reason some of them choose petrol engines.

[wstander]

It all comes down to the way you use the car.


Conclusion: 80% of the population's driving style is better suited to the Diesel, but for some reason some of them choose petrol engines.

Or, they live somewhere that diesel is, or nearly is banned....like California. in the late 1990s and early 2000s, it was almost criminal to own a diesel powered car there....not sure it is viable here yet;)

[Ferrer]

Many argue for the emotional qualities of the petrol engine, like the higher revving character and the sound. True, but this realistically applies only to sports cars. If someone buys a Mondeo 3.0 V6, then he is wasting his petrol over a bad chassis.
Precisely. Say you need a family car. For the car enthusiast what should it be the ST220 or the 2.2 litre diesel?

(And I always thought the Mondeo had a very decent chasis)

[lightweight]

Or, they live somewhere that diesel is, or nearly is banned....like California. in the late 1990s and early 2000s, it was almost criminal to own a diesel powered car there....not sure it is viable here yet;)

True, but since the topic states diesel or hybrid, I kind of excluded Hybrids or electric cars.

Normally Diesels in Europe serve the same purpose as Hybrids in the US. You pay a price premium when you buy the vehicle in order to be able to capitalise on its fuel economy and break even on fuel costs.

The only difference with Hybrids is that since the price premium over equivalent petrol cars is bigger than Diesel, the time needed to break even is also bigger.

Now for the REAL conclusion:

- Most Diesel and Hybrid buyers buy a new car before they break even on the price premium of their car.

- Diesel is more harmful to the environment than equivalent petrol engines (comparing same Carbon Dioxide figures)

- Diesel and Hybrids save on Carbon Dioxide emissions, but in order to be manufactured, lots of toxic materials are being used, that aren't treated in any way after the vehicle ends its life. So we are in a state where we are proud of reducing CO2 emissions, but we are blind towards toxic pollutants poisoning us and creating all-time high cancer readings.

Hmm... Seems that I widened the topic here a little bit...

[lightweight]

Precisely. Say you need a family car. For the car enthusiast what should it be the ST220 or the 2.2 litre diesel?

(And I always thought the Mondeo had a very decent chasis)

It all boils down to someone preferences as I mentioned earlier.

I don't think that driving 300 Nm of high end Petrol torque through the front wheels offers satisfaction to the "sporty" driver when going through a corner.

On the contrary 300 Nm of low-down diesel grunt that enables you to effortlessly cruise on the Motorway with minimal fuel consumption, is a much more logical solution.

Someone of course might fancy torque steer etc (After all there are people who buy Astra OPC / VXR).

[wwgkd]

Or, they live somewhere that diesel is, or nearly is banned....like California. in the late 1990s and early 2000s, it was almost criminal to own a diesel powered car there....not sure it is viable here yet;)

California does it's own thing regardless of what's actually intellegent. Don't even get me started on that state.

I'd say that diesel vspetrol really depends on the application. I'm a huge diesel fan, but even I think that they should be kept out of sports cars. Sure, diesel race cars have been dominating some arenas, but a sports car should be about the driving experience and for the reasons you mentioned diesels can fall short in a little sporty car.

However there are a lot of areas where diesels can be superior and I think continuing to develop diesel technology for more applications is a good thing. Some day diesels may match petrol in areas where today they seem like sacrilege.

[clutch-monkey]

i'm a big fan of diesel 4X4's, hilux, particularly the nissan patrol utes and the like.
there is precisely zero chance of me having diesel in any road car i own at the moment however. i will start distilling my own ethanol blend haha.
would consider it when the time comes round for a family car, but it is unlikely.

[P4g4nite]

I love the idea of diesels and I'm toying with the idea of getting a really cheap diesel project car..but I've never actually driven a diesel I liked. Dad has a new turbo diesel Ranger and sure it uses no fuel at all, but the powerband feels like it is about 100rpm wide.

[coolieman1220]

i need to drive some diesel's see waht its like! i'm very interested in them. all that torque and low rpms!

[allangering]

Diesel cars are more fuel-efficient than petrol-driven ones - burning a litre of diesel creates more CO2 than burning a litre of petrol, but the engine efficiency just about makes up for that. However, diesel will create more dirty emissions such as nitrogen oxides and particulates that can affect health. If you are considering buying a diesel car, choose one with a diesel particulate filter,as this will reduce these emissions.

[LeonOfTheDead]

remember that the lag of a diesel is also due to the "combustion" process. Using the same turbo and same specs and all, a petrol car will still have less lag than a diesel one.

[lightweight]

remember that the lag of a diesel is also due to the "combustion" process. Using the same turbo and same specs and all, a petrol car will still have less lag than a diesel one.

Not sure myself, but given that the Diesel has a very high compression ratio (Maybe 20:1 and upwards), I would expect that the Diesel wouldn't be laggy

[LeonOfTheDead]

Not sure myself, but given that the Diesel has a very high compression ratio (Maybe 20:1 and upwards), I would expect that the Diesel wouldn't be laggy

The process of vaporizing and mixing the fuel with the air takes more time than in a petrol car, due to the viscosity and density of the diesel. the high compression ratio of a diesel is also lower than what it used to be, while petrol engines are adopting higher ones than in the past.

[Ferrer]

Not sure myself, but given that the Diesel has a very high compression ratio (Maybe 20:1 and upwards), I would expect that the Diesel wouldn't be laggy
I cannot quite get into the technicalities of it, like Damiano can, but comparing the Delta and the BMW, the bimmer has far more lag despite a 600cc advantage over the petrol engine.

[charged]

Im with P4g4nite I have a t/d manual hiace as a work car and I swap cogs in that more than the race car. It can be very dangerous when merging with traffic if your in the wrong gear and off boost. The modern turbo diesel is like the old school big boost turbo from 20yrs ago its all or nothing and when its on boost when they start accelerating it time to changer gear.

The T/D are much better in auto were the converter keeps them on boost but in manual a big NO THANKS

[IBrake4Rainbows]

Bear in mind a lot of what Ferrer et al from Europe are talking about are very advanced Diesel cars with some seriously good tech that make sense.

The fact remains In Australia at least the quality of the fuel is not good enough to support these advanced engines. Diesel is still a fairly nasty, dirty and rough blend around these parts. I suppose if the demand exists for the higher quality stuff then it will come about, but for the moment the savings of running a diesel (discounting the higher purchase price of both vehicle & fuel in Australia) and Petrol still makes a strong argument.

[Ferrer]

Bear in mind a lot of what Ferrer et al from Europe are talking about are very advanced Diesel cars with some seriously good tech that make sense.

The fact remains In Australia at least the quality of the fuel is not good enough to support these advanced engines. Diesel is still a fairly nasty, dirty and rough blend around these parts. I suppose if the demand exists for the higher quality stuff then it will come about, but for the moment the savings of running a diesel (discounting the higher purchase price of both vehicle & fuel in Australia) and Petrol still makes a strong argument.
And then as nota tells us all the time there's LPG for you.

[LeonOfTheDead]

And then as nota tells us all the time there's LPG for you.

That's a good option in Italy as well, the after market industry is so good half of the standard LPG system from car makers is actually an after market unit just fitted since the beginning.

[IBrake4Rainbows]

LPG is a cheap option, for sure.

It's just not for everyone, because it's still a little mystical for some....

[Ferrer]

Another thing I've noticed is that the Lancia has better in gear acceleration than the BMW. Of course this could be due to a number of factors not directly related to the engines in question, but nevertheless it surprised me.

(Fast Van, by the way...)

[Lagonda]

IMHO, petrol is dead for daily driving. In Europe, that is.

Sure high revving petrol engines are great fun but not in the traffic conditions we face these days.
Look at the next generation BMW 35d engine: 306bhp. Just like the 35i engine. 600nm of torque at 1500 rpm... (400nm at 1200 rpm for the petrol) And a fuel consumption that's probably half of what the petrol engine needs.

The only reason I can think of to get the 35i would be the sound.

These engines are obviously two extreme examples. Rarely seen on the road. But the same is true for more "normal" engines. Almost every time the diesel is the more sensible choice. Financially petrol engines are the worst choice you can make unless you do very little miles.
Noise, smoke, slow turbo etc. are non issues these days. Keep in mind that most (found in most normal cars) petrol engines are "all or nothing" as well. Sure it's linear but you need to get into the high revs before it really starts going, everything below is a snoozefest.

Hybrid diesels will even widen that gap. Hybrid petrol is a joke, just about any modern diesel uses less fuel.

That said my next car will be a little diesel. I'll miss hitting 6500rpm but my wallet won't.
It hurts to say this, being a car nut, but petrol is really for the rich or for a weekend car over here.

[lightweight]

Hybrid petrol is a joke, just about any modern diesel uses less fuel.

True, and the diesel has more power.

But try and tell that to the public in the US, that the Diesel is more economical than the equivalent hybrid.

I mean lots of British episodes of Fifth Gear have made direct comparisons of Diesel VS Hybrid and the Diesel is cheaper, faster, more economical EVERY TIME!!

[ruim20]

IMHO, petrol is dead for daily driving. In Europe, that is.

Sure high revving petrol engines are great fun but not in the traffic conditions we face these days.
Look at the next generation BMW 35d engine: 306bhp. Just like the 35i engine. 600nm of torque at 1500 rpm... (400nm at 1200 rpm for the petrol) And a fuel consumption that's probably half of what the petrol engine needs.

The only reason I can think of to get the 35i would be the sound.

These engines are obviously two extreme examples. Rarely seen on the road. But the same is true for more "normal" engines. Almost every time the diesel is the more sensible choice. Financially petrol engines are the worst choice you can make unless you do very little miles.
Noise, smoke, slow turbo etc. are non issues these days. Keep in mind that most (found in most normal cars) petrol engines are "all or nothing" as well. Sure it's linear but you need to get into the high revs before it really starts going, everything below is a snoozefest.

Hybrid diesels will even widen that gap. Hybrid petrol is a joke, just about any modern diesel uses less fuel.

That said my next car will be a little diesel. I'll miss hitting 6500rpm but my wallet won't.
It hurts to say this, being a car nut, but petrol is really for the rich or for a weekend car over here.

I agree, my next car will most likely be a diesel or a factory prepared LPG. In terms of economy there is no comparing, all in all you just have to do the math. Gasoline can only have a future in europe if an engine revolution happens like it did in the diesels.
Maybe a weekend car, a used MX-5 1.6 or a Smart Roadster, but thats it.

In a month i'll be doing about 60kms every day, if the road where flat i'd opt for an LPG, as it's hilly i'll be searching for a diesel in the 100bhp + category, Wich will be more economical than my 1.2 80bhp petrol, sad.

Note: i will only buy a new/used car when the current one really falls apart, as it is, i save more by keeping this running than buying a new car.

[Ferrer]

I agree, my next car will most likely be a diesel or a factory prepared LPG. In terms of economy there is no comparing, all in all you just have to do the math. Gasoline can only have a future in europe if an engine revolution happens like it did in the diesels.
Maybe a weekend car, a used MX-5 1.6 or a Smart Roadster, but thats it.

In a month i'll be doing about 60kms every day, if the road where flat i'd opt for an LPG, as it's hilly i'll be searching for a diesel in the 100bhp + category, Wich will be more economical than my 1.2 80bhp petrol, sad.

Note: i will only buy a new/used car when the current one really falls apart, as it is, i save more by keeping this running than buying a new car.
There's indeed no contest in the financial department. Especially if you do high mileage.

But, still and since Lagonda brought up the example, it'd be so hard to say no to a 335i.

[Lagonda]

it'd be so hard to say no to a 335i.

Sure, if someone else is paying. :p

It's a whole other game if running costs aren't important. Bring on that big 6-cyl, V8, V12, V-whatever petrol engine !

[VOGUE_MAN]

The evolution of diesels has been rapid, in Australia even the last three years has seen giant leaps in diesel engine and it's now to the point where I can barely see the point of petrol accept for high performance race/road cars and if the R8 V12TDI had of happened even petrol in high perforance may have come into question.
For every other type of vehicle though, there's a diesel engine to suit. Tiny cars have incredibly low fuel usage, with a chip a TDV8 Landcruiser can have over 800nm or torque and still get under 11 litres per 100km. Or if you still want to feel like you're driving something sporty test drive a BMW 330D, A small car with 180kw and 480nm of torque, obviously it won't compare to an eight cyclinder engine but it's a lot of power for a 3 series.

[LeonOfTheDead]

Today I was walking in downtown. A guy in a diesel Citroen C2 stopped at the crossing lights.
It was vibrating.

[henk4]

Today I was walking in downtown. A guy in a diesel Citroen C2 stopped at the crossing lights.
It was vibrating.

the crossing light?

[LeonOfTheDead]

the crossing light?

not, that was fine, I was talking about the car, and the guy as well.
Being completely honest though, I had several rides in a petrol C2, and it was worst than my mother's old 1991 Clio.

Finally, I never drove a petrol Stilo, but our diesel, while not falling apart, is made of vibrations.

[henk4]

Finally, I never drove a petrol Stilo, but our diesel, while not falling apart, is made of vibrations.
we have a petrol stilo and apart from falling apart, it also suffered (financially quite painfully) from ignition glitches.

[LeonOfTheDead]

we have a petrol stilo and apart from falling apart, it also suffered (financially quite painfully) from ignition glitches.

which engine was it? just curious, as here basically now onw bought them with petrol engines (just a few underpowered 1.2 16V)
(the old 156 1.9 JTD has a similar problem btw)

[Ferrer]

the crossing light?
Concentrate on fuel savings and performance, you've got higher chances there. :)

[henk4]

which engine was it? Just curious, as here basically now onw bought them with petrol engines (just a few underpowered 1.2 16v)
(the old 156 1.9 jtd has a similar problem btw)
1.6 16v 100 bhp.

[Revo]

How about some irony.

Unlike petrol drivers, modern diesel drivers are required to drive with high revs every now and then. So all the accumulated soot in the DPF can burn correctly.

In other words - if you want to drive economically, occasionally you have to drive uneconomically. Makes sense.

[henk4]

How about some irony.

Unlike petrol drivers, modern diesel drivers are required to drive with high revs every now and then. So all the accumulated soot in the DPF can burn correctly.

In other words - if you want to drive economically, occasionally you have to drive uneconomically. Makes sense.
so petrol engines do not require a regular "clean-up revving" these days anymore??

[LeonOfTheDead]

so petrol engines do not require a regular "clean-up revving" these days anymore??

Not particularly, if we are considering everyday cars.

The ECU should clean the soot away regardless of how you drive though, so even if you're trying to keep the revs low (and it doesn't mean you are using less fuel) the engine would run on higher revs to do the dirty job.

At the end of the day you burned some additional fuel nonetheless:)

[henk4]

Not particularly, if we are considering everyday cars.

The ECU should clean the soot away regardless of how you drive though, so even if you're trying to keep the revs low (and it doesn't mean you are using less fuel) the engine would run on higher revs to do the dirty job.

At the end of the day you burned some additional fuel nonetheless:)

so it does not affect an engine any more, if a car has only been driven by an elderly lady....

[LeonOfTheDead]

so it does not affect an engine any more, if a car has only been driven by an elderly lady....

as with a diesel engine, the ECU drives the engine, not the driver anymore.
Then give an Honda S2000 to my grandma and we'll pay for our actions...

[group c n b man]

Each one has it's pros and cons however I think on the road diesel fuel edges out petrol fuel. And on the racetrack aswell come to think of it!(Audi R10, Audi R15, Peugeot 908). On the motorway a diesel will tickover at very low revs and will get about 65mpg, a petrol engine of the same displacement would get around 45mpg, maybe. Around town, diesel is much easier to drive (assuming both are manual boxes) than a petrol. In a diesel, as I've discovered, there is a "biting zone" as opposed to a "biting point". This means that when waiting at lights or stopped on a hill, you can hold the clutch at the "biting zone" and your other foot on the brake. This allows you to creep forward with complete control, with no fear of embarassment. If you were to do this in a petrol, you would either stall the engine or roll back, both of which are undesirable. Diesel is also more environmentally friendly than petrol. Modern diesels can be incredibly fast and accelerative thanks to the huge torque that they create.
Petrol's only real advantage is when driving for the sheer pleasure of it. The engine sound is far more exciting and nice than diesel which sounds rather boring in comparison. Diesel technology has come on massively in relation to petrol technology in the last 15 years or so, however, petrol is still the fuel of choice amongst most of us enthusiasts. As Leonofthedead said, your heart says petrol but your head says diesel.

[LeonOfTheDead]

A few things wrong.
Diesel isn't more environmentally friendly than petrol. It is indeed facing problems with future emissions laws, while petrol is not.
Second, we aren't talking about a plain field, as a few of the technical solution applied to diesel engines is applied to petrol ones.
About the fuel economy, most diesel achieve their superior figure if driven properly. That's correct with petrol cars as well. The thing is, as a fact, people tend to drive faster in petrol cars rather than in diesel ones, during the span of a whole year and not just on a spirited day.
If you think about of the excellent twin turbo engine from BMW, it achieves plenty of power and torque basically at all rpms. The fuel consumption isn't as good in its diesel counterpart, but the petrol one doesn't have direct injection, VGT turbos and 15 years of experience at its back, just to say the main features.
Have a look at recent turbocharged small petrol engines, like those in the Abarth, and you'll see excellent performance, less lag, and an impressing mileage considering the outputs. Once again with less new technology applied than in diesels, which on the contrary are at a dead point lately (with no major improvement in the foreseeable future).

I like diesel as a daily drive, it's easier and so on, but I can't avoid thinking petrol engine are taking over, quickly.

[jcp123]

so petrol engines do not require a regular "clean-up revving" these days anymore??

Not on injeced vehicles in proper tune. Carbureted ones like mine need to clear their throats now and then though. I had some carbon holding a valve open last spring; ran rough, it was missing, and generally sounded sick. One WOT run and it was cleared, no problems since.

Anyhow, I'd vote for diesel. They are some of the few modern/new cars I'd consider owning.

[henk4]

If you think about of the excellent twin turbo engine from BMW, it achieves plenty of power and torque basically at all rpms. The fuel consumption isn't as good in its diesel counterpart, but the petrol one doesn't have direct injection, VGT turbos and 15 years of experience at its back, just to say the main features.
That's strange, are you saying that BMW has less than 15 years experience in producing (turbo) petrol engines? Apart from the 2002 they already had the 3.3 L in the mid seventies as well...sounds like a bit more than 15 years.
You are probably hinting at the fact that concerted technology development in diesel engines has produced such great results in a relatively short period of less than 15 years. (Common Rail 1998??).
And what would stop BMW from applying these VGT turbos and DI to the petrol car??

[henk4]

In a diesel, as I've discovered, there is a "biting zone" as opposed to a "biting point". This means that when waiting at lights or stopped on a hill, you can hold the clutch at the "biting zone" and your other foot on the brake.

I agree with what you say about using that technique on a hill. You hardly need to use the handbrake any more to get going. To apply this for a light, with a slightly slipping clutch, looks to me rather unnecessary as also clutches do not have eternal life. You will eventually feel the biting point in your wallet.

[lightweight]

Diesel isn't more environmentally friendly than petrol.

It depends on the type of emission examined. For the same performance a Diesel emits less Carbon Dioxide, but more NOx.


About the fuel economy, most diesel achieve their superior figure if driven properly.

That is correct, but it also applies to petrol engines. Porsche claim about 10 lt/100 km for the 3.8 Carrera. Floor it and you will see 3-4 times that figure.

A direct and specific comparison can only be made on equal terms. So, official MPG figures, although differing from real world conditions, can be seen comparatively for the relative consumption of engines.

[henk4]

A direct and specific comparison can only be made on equal terms. So, official MPG figures, although differing from real world conditions, can be seen comparatively for the relative consumption of engines.

whereby the excesses achievable with a petrol engine are far greater than with a diesel...

[lightweight]

whereby the excesses achievable with a petrol engine are far greater than with a diesel...

In absolute terms yes.

My understanding on the topic is that if two engines have a 20% difference in official manufacturer MPG, then this difference will more or less exist if driven hard. But the 20% consumption difference on 50 MPG is much smaller than the 15 MPG in terms of pump money!!

Any insights on this?

[LeonOfTheDead]

That's strange, are you saying that BMW has less than 15 years experience in producing (turbo) petrol engines? Apart from the 2002 they already had the 3.3 L in the mid seventies as well...sounds like a bit more than 15 years.
You are probably hinting at the fact that concerted technology development in diesel engines has produced such great results in a relatively short period of less than 15 years. (Common Rail 1998??).
And what would stop BMW from applying these VGT turbos and DI to the petrol car??

I mean with recent turbocharging application. Things changed a bit since the 2002. The 6 cylinders diesel engine received much more attention and updates or innovations in the last 15 years than their petrol counterpart which were somehow "ignored".

The reason why no one right now is adopting both DI and VGT in turbocharged petrol engines is because it isn't required by the market.
A quite simple engine as the new Fiat 1.4 unit, with just a modern turbo and good load of electronics, is sufficient to have everyone happy with the performance and the mileage. The same goes for the 3.0 twin turbo from BMW. It is already powerful and relatively frugal, adding more technology wouldn't justify an even higher price tag (people wouldn't justify it), and as everyone else would be doing the same, the result would have been once again a plain field, but using all at once all your updates instead of diluting them in another 15 years.
Everything is already present and usable, it isn't a sensible choice from a economical and marketing point of view though.
Porsche introduced the VGT in the 911 Turbo engine to keep the brand emissions down, and give a bit of hi-tech touch to a car that this time has little new to offer, especially if you think that the bump in power was limited compared to the outgoing 996.
So marketing once again.
It would have been a sensible choice to adopt them in the Panamera, but those engines come straight from the Cayenne, so an "older" project, but also from Audi.
Then there is the case of this "modern" technology not properly applied and resulting in a useless amount of money spent with zero results.
An example I already posted is the Renault 1.2 turbo engine in the Twingo GT (perhaps now updated), versus the 1.4 naturally aspirated unit in the Fiat 500.
The Fiat unit is nothing new, just a good old engine with a good tune.
The Renault engine has DI and turbocharging, still it manages/manage to achieve the same performance and a barely lower fuel consumption.

My point with diesel, elabprated talking with a teacher at University, is that diesel engines were used as a sort of "scapegoat".
With the state of the art of the pre-common rail era, diesels were unpopular, noisy and overwhelmingly performing. Only VAG with the 1.9 unit was showing some results, but it was a dead end as we would have later seen.
The point was developing "new" technologies and parts for petrol engines, commercialize them and leaving diesels alone, or give a spark of life (lol) to the diesel project, let it evolve until its limit, and then move back again on petrol transferring the technology meanwhile developed fir the oil burner.
This was you would have diluted the costs on two "products", rather than one only, and you would have used also the potential of the diesel.
Developing since the beginning the petrol engine would have killed the diesel since the beginning, as i would have been soon reached a point where petrol where simply better and "no one" would have bought a diesel again no matter how good it was.

So in the last 15 years or so, diesel received a lot of attentions and a lot of money was spent. A huge amount of result were achieved though, not only technically but also in cars sold. I don't think they didn't even expect such a success of citycars equipped with diesel engines.
No we reached a limit where power of diesel is increasing much slower than a couple of years ago, and only in larger engines (therefore higher consumptions and emissions) seem to be still gaining something (thinking of the recently updated Jaguar/PSA 3.0 V6).
Behind the 2.0 liter mark the diesel engine have a thinner margin on the petrol one, the power is generally the same if not lower, surely more torque (thanks to the turbocharcing), but the mileage isn't that lower especially if compared to larger diesel engines or even petrol engines of the same displacement. Still they cost at least 2.000 € more.

Not only the performance are now "stationary", but difficulties meeting the upcoming stricter emissions laws are raising (as foresee by the same automakers at least 5 years ago or more), while just adopting what has been developed for a diesel unit to a petrol engine gives back excellent result, at virtually very low costs, both in performance and emissions levels.
So right now, the petrol engine is showing bigger and simpler margins of improvements, and investments on it are being huge since some years.
Once again, not everything is applied all at once, since it isn't necessary to achieved the required results, and also to give some more years (about ten, we agreed) to the diesel units, so to enlarge even more the profits on that project.

This doesn't exclude a come back of the diesel engine in the future obviously.


It depends on the type of emission examined. For the same performance a Diesel emits less Carbon Dioxide, but more NOx.

Sure, still CO2 can be reduced on a petrol car, NOx not, in a diesel (and the urea based technology proved to be a sort of marketing failure).



That is correct, but it also applies to petrol engines. Porsche claim about 10 lt/100 km for the 3.8 Carrera. Floor it and you will see 3-4 times that figure.

A direct and specific comparison can only be made on equal terms. So, official MPG figures, although differing from real world conditions, can be seen comparatively for the relative consumption of engines.

I elaborated this in my previous post.
The main problem is that no one is going to drive slowly a 911 all the year, sooner or later, probably everyday, you're going to use all it's power.
On the other hand, diesel are generally driven more quietly.



whereby the excesses achievable with a petrol engine are far greater than with a diesel...

That's correct at the same time, but also the gain in performance is higher (once again thinking on similarly technologically equipped engines, just think of the 1.3 diesel and 1.4 petrol units from Fiat, both turbocharged and the petrol with no DI).

[Ferrer]

Damiano, the problem is, if you push a diesel and a petrol engine the fuel consumption in the petrol engine will increase much more dramatically than the diesel engine. You argue that diesels are usually driven more sedately but still, as I said you can't argue with 7l/100km at 180km/h.

[LeonOfTheDead]

Damiano, the problem is, if you push a diesel and a petrol engine the fuel consumption in the petrol engine will increase much more dramatically than the diesel engine. You argue that diesels are usually driven more sedately but still, as I said you can't argue with 7l/100km at 180km/h.

That correct, but have you driven a modern petrol engine at that speed?
I don't, and I would be very curious to know the figure it gives.
Surely I'm very happy with the mileage of the Stilo on the motorway, at 130-150 km/h it gives back 5 or 6 L/100 km at worst.

The point of my discussion is: we are know talking about top of the line diesel engines, at the apex of their development, and about still to be updated petrol engines, which just for a reason of marketing were relegated in the last years on a second level.

If it sounds like I'm saying "petrol is superior", that's not the tone I'd use, rather "petrol is easier to work with to achieve better results".
It was surely a sensible and smart idea to divide the development costs of the technologies on both engines, we all gained with that.

[Ferrer]

That correct, but have you driven a modern petrol engine at that speed?
I don't, and I would be very curious to know the figure it gives.
Surely I'm very happy with the mileage of the Stilo on the motorway, at 130-150 km/h it gives back 5 or 6 L/100 km at worst.

The point of my discussion is: we are know talking about top of the line diesel engines, at the apex of their development, and about still to be updated petrol engines, which just for a reason of marketing were relegated in the last years on a second level.

If it sounds like I'm saying "petrol is superior", that's not the tone I'd use, rather "petrol is easier to work with to achieve better results".
It was surely a sensible and smart idea to divide the development costs of the technologies on both engines, we all gained with that.
Actually I have. The little 1400cc under the Delta's bonnet is a gem, but at those sort of speeds it likes to drink. And especially if you find slower traffic in the left lane. Then it's going 120-180km/h in sixth, foot down all the way. And economy suffers greatly. Haven't done the math, if I can I'll do them this week, but I'd say that at least you'd be getting 9-10l/100km in Delta, if not more.

[lightweight]

The point of my discussion is: we are know talking about top of the line diesel engines, at the apex of their development, and about still to be updated petrol engines, which just for a reason of marketing were relegated in the last years on a second level.

From my point of view we are discussing what is available in the market. I would agree that petrol engines will benefit from a few technologies coming in the following years (HCCI, hydraulic valves) but such technologies are very expensive and still will not beat Diesels in MPG.

So the question is the price of the future engines relative to the MPG. That is a question that I am afraid no one in this forum can answer:(

I really think that the future of the petrol engine for urban applications is the DiesOtto - Wikipedia, the free encyclopedia engine presented back in 2007 by Mercedes-Benz. So there is no point in talking petrol vs Diesel as they could merge:)


Sure, still CO2 can be reduced on a petrol car, NOx not, in a diesel

As far as I know, Siemens is planning to introduce higher pressure piezo-injectors that will further reduce NOx.

[LeonOfTheDead]

From my point of view we are discussing what is available in the market. I would agree that petrol engines will benefit from a few technologies coming in the following years (HCCI, hydraulic valves) but such technologies are very expensive and still will not beat Diesels in MPG.

So the question is the price of the future engines relative to the MPG. That is a question that I am afraid no one in this forum can answer:(

I really think that the future of the petrol engine for urban applications is the DiesOtto - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/DiesOtto) engine presented back in 2007 by Mercedes-Benz. So there is no point in talking petrol vs Diesel as they could merge:)



As far as I know, Siemens is planning to introduce higher pressure piezo-injectors that will further reduce NOx.

HCCI and DiesOtto are, I think, still too far from the production line, and so seems to be hydraulic valves.
I'm ust considering VGT applied to (sequential) twin turbos laoyt matched to a DI system, on a petrol engine that is. Something that could be done tomorrow with no particular cost. And I think it would provide tremendous results.

[LeonOfTheDead]

Actually I have. The little 1400cc under the Delta's bonnet is a gem, but at those sort of speeds it likes to drink. And especially if you find slower traffic in the left lane. Then it's going 120-180km/h in sixth, foot down all the way. And economy suffers greatly. Haven't done the math, if I can I'll do them this week, but I'd say that at least you'd be getting 9-10l/100km in Delta, if not more.

The 1.4 is a gem, still lack a few updates, see the Alfa Romeo MiTo MultiAir.
BTW, with which engine are you achieving the 7 L/100 km?
Do you think the 1.3 diesel from Fiat, which barely achieve the 100 bhp mark, would give such figure at 180 km/h, provided you can reach that speed?

[john14]

I've only driven a petrol cars. Modern diesel cars are very impressive but I think many people still think diesel is bad due to the images that are stuck in the minds of many people. This image is of large 1970s diesel trucks. You would see so much nasty looking black smoke coming from those trucks and many people still willl only buy a petrol car because of the bad visual image they see when they think of diesel. Modern diesel cars and trucks are much cleaner and better for the environment but most people seem to ignore that.

[Ferrer]

The 1.4 is a gem, still lack a few updates, see the Alfa Romeo MiTo MultiAir.
BTW, with which engine are you achieving the 7 L/100 km?
Do you think the 1.3 diesel from Fiat, which barely achieve the 100 bhp mark, would give such figure at 180 km/h, provided you can reach that speed?
No I doubt the 1300cc diesel would do 7l/100km at 180km/h. Altough I doubt you can reach such as speed in it even downhill...

I was comparing the Delat to the 118d. Both have around 150bhp and both are hatchbacks that weight more or less the same. If we look at fuel consumption only, the diesel wins, no matter what speed you pick.

[LeonOfTheDead]

No I doubt the 1300cc diesel would do 7l/100km at 180km/h. Altough I doubt you can reach such as speed in it even downhill...

I was comparing the Delat to the 118d. Both have around 150bhp and both are hatchbacks that weight more or less the same. If we look at fuel consumption only, the diesel wins, no matter what speed you pick.

The 118d has also a larger engine though, which is something good at such speed.

[Ferrer]

Alright this afternoon I had a relatively long spirited (135km, 50km/h average) drive on local country roads and the trip computer says 11,6l/100km. The Bimmer would've been under 10l/100km comfortably in the same conditions.

We'll see how the full tank pans out in the Lancia.

[henk4]

Alright this afternoon I had a relatively long spirited (135km, 50km/h average) drive on local country roads and the trip computer says 11,6l/100km. The Bimmer would've been under 10l/100km comfortably in the same conditions.

We'll see how the full tank pans out in the Lancia.

spirited drives in a diesel will not require red line revving to get satisfactory forward movement. That 's where you gain in MPG. (problem that many people will call this type of driving not "spirited", because it lacks the emotion of a noisy engine)

[LeonOfTheDead]

spirited drives in a diesel will not require red line revving to get satisfactory forward movement. That 's where you gain in MPG. (problem that many people will call this type of driving not "spirited", because it lacks the emotion of a noisy engine)

but have more torque motivating your day, so it's not annoying at all.
I still prefer the simple turbo of the Stilo rather than the VGT of the Croma though.

[henk4]

but have more torque motivating your day, so it's not annoying at all.
I am not complaining;)
as the great Carroll Shelby once said:
"Horsepower sells cars, torque wins races...".

[LeonOfTheDead]

About the sound, I don't think there are many ordinary cars/engines with a really good sound, being diesel or petrol. Of course the sound of a diesel car isn't comparable to a supercar with ceramic exhausts, but they are also two completely different cars presumingly.
I don't think a 1.6 petrol engine objectively sounds under the bonnet of a Stilo or 308, same goes for their diesel counterpart.
Now if we could consider a diesel V6 from MB and the lovely petrol V6 from Alfa Romeo...

[henk4]

About the sound, I don't think there are many ordinary cars/engines with a really good sound, being diesel or petrol. Of course the sound of a diesel car isn't comparable to a supercar with ceramic exhausts, but they are also two completely different cars presumingly.
I don't think a 1.6 petrol engine objectively sounds under the bonnet of a Stilo or 308, same goes for their diesel counterpart.
Now if we could consider a diesel V6 from MB and the lovely petrol V6 from Alfa Romeo...
there is (justified) increasing social objection against loud vehicles, (not from the drivers, but from those around it)...Most people with less mechanics in their blood will not be able to fully appreciate the sound of the Alfa for what it is, but just consider it to be excessive engine noise, when revved high.

[Ferrer]

spirited drives in a diesel will not require red line revving to get satisfactory forward movement. That 's where you gain in MPG. (problem that many people will call this type of driving not "spirited", because it lacks the emotion of a noisy engine)
I wasn't redlining the Lancia either.

there is (justified) increasing social objection against loud vehicles, (not from the drivers, but from those around it)...Most people with less mechanics in their blood will not be able to fully appreciate the sound of the Alfa for what it is, but just consider it to be excessive engine noise, when revved high.
Keep it quiet in the city, push it on the nountains. :)

[henk4]

Keep it quiet in the city, push it on the nountains. :)
we are flatlanders.

[Ferrer]

we are flatlanders.
Push it in local roads where there's no one.

[LeonOfTheDead]

That's why I'm pro hybrids, total silence and zero emissions in overcrowded areas, blast elsewhere.

[henk4]

Push it in local roads where there's no one.

ever been here?

[henk4]

That's why I'm pro hybrids, total silence and zero emissions in overcrowded areas, blast elsewhere.

as a pedestrian or cyclist I like to hear a car coming up behind me. The familiar subtle rattle of a diesel is a much more alerting sound than the wind and tyre noises of an electro-car. (the ability to look over your neck decreases with age...)

[Ferrer]

ever been here?
No. You truly don't have any proper drivers roads?

as a pedestrian or cyclist I like to hear a car coming up behind me. The familiar subtle rattle of a diesel is a much more alerting sound than the wind and tyre noises of an electro-car. (the ability to look over your neck decreases with age...)
I can relate to this. When we tested the Prius, before getting in the car, another Prius came behind us and we didn't notice it. We didn't hear it.

[LeonOfTheDead]

as a pedestrian or cyclist I like to hear a car coming up behind me. The familiar subtle rattle of a diesel is a much more alerting sound than the wind and tyre noises of an electro-car. (the ability to look over your neck decreases with age...)


No. You truly don't have any proper drivers roads?

I can relate to this. When we tested the Prius, before getting in the car, another Prius came behind us and we didn't notice it. We didn't hear it.

So we should all drive screaming Ferrari V12 cars with rpm between 6.000 and 8.000 with the youngest population more and more into screaming iPods, while crossing the street, driving the bicycle and so on.
I can see the point, and I actually think we should pay more attention. A minimum level of sound emitted, even if it's a contradiction with trying to diminish the overall pollution (noises included), could be welcomed, but there is a limit even to what we should do ourselves to save our life.

As a mainly bicycle driver, I'd prefer a cleaner air than an engine alerting me "hey, you can't cross the road without looking back!".
As a car driver, I often can't see the need of an ICE when driving in downtown, without even considering how many energy we waste accelerating and braking when not necessary. Just put the gearbox into neutral at 60 km/h and you'll see where you could go, driving in town. Presumingly there will be the need to stop or brake for a pedestrian crossing or a light crossing before you'll reach a too low speed in many cases.We can talk about the sound, but I think hybrids are a quite sensible choice right now.
NOT saying a Prius is better than anything else, just talking about the idea behind hybrid cars, no consideration on their costs, political implications and so on.

[Ferrer]

In the city yes hybrids are nice. The use less fuel than diesels and the silence, while as we discussed has some safety implications, is nice. However in the city you need a small car and yet most hybrids are big family cars or SUVs, which kind of contradicts the point.

And when you get on the open road, at the speeds that are driven in Europe, hybrids are soundly thrashed by diesels. I can see the point of hybrid but not as it is now. And in any case, why make petrol powered hybrids? If you really want to save money what you want is a diesel-powered hybrid.

[LeonOfTheDead]

In the city yes hybrids are nice. The use less fuel than diesels and the silence, while as we discussed has some safety implications, is nice. However in the city you need a small car and yet most hybrids are big family cars or SUVs, which kind of contradicts the point.

And when you get on the open road, at the speeds that are driven in Europe, hybrids are soundly thrashed by diesels. I can see the point of hybrid but not as it is now. And in any case, why make petrol powered hybrids? If you really want to save money what you want is a diesel-powered hybrid.

Simply because there is few room left in the engine bay of a diesel powered car. Also a diesel engine is already heavier than a petrol one. This are the first reasons I can think of. Than there is also the fact of diluting the innovations, why to sell diesel hybrids when a petrol diesel already provides an improvement?

Right now hybrids are surely a minor part of the market and aren't enough considered both buy the makers and the owners (not considering go-gree-maniacs).
Personally, I can't wait for the first Fisker Karma to be properly reviewed.

[wwgkd]

I think in this hybrid diesel dabate you're missing a couple key points.

1. Diesels are expensive, and hybrids are expensive, so diesel electric hybrids, while the most effecient, are also the most expensive (in their class.) That's why you don't see more of them right now.

2. Hybrids have the battery problem. Very messy to make and just as bad to dispose of. Those battery packs only last 100,000 miles right now and are almost as hard to dispose of as nuclear waste (ask japan about that, they're pretty mad at the us and canada for shipping our old packs back to them.) People think zero emissions in electric mode and completely forget that it's a whole system, no just whats going on when you drive.

[lightweight]

I think in this hybrid diesel dabate you're missing a couple key points.

1. Diesels are expensive, and hybrids are expensive, so diesel electric hybrids, while the most effecient, are also the most expensive (in their class.) That's why you don't see more of them right now.

2. Hybrids have the battery problem. Very messy to make and just as bad to dispose of. Those battery packs only last 100,000 miles right now and are almost as hard to dispose of as nuclear waste (ask japan about that, they're pretty mad at the us and canada for shipping our old packs back to them.) People think zero emissions in electric mode and completely forget that it's a whole system, no just whats going on when you drive.

True. I think what you said highlights a bigger and more extended issue:

Mankind has recently become concerned about the environment and searches for ways to reduce its negative impact. Unfortunately all this effort goes into carbon emissions and does not even mention toxic / nuclear waste disposal.

Given that there is an energy trend in the Western countries towards Nuclear energy generation, such issues must be adressed

[LeonOfTheDead]

I think in this hybrid diesel dabate you're missing a couple key points.

1. Diesels are expensive, and hybrids are expensive, so diesel electric hybrids, while the most effecient, are also the most expensive (in their class.) That's why you don't see more of them right now.

2. Hybrids have the battery problem. Very messy to make and just as bad to dispose of. Those battery packs only last 100,000 miles right now and are almost as hard to dispose of as nuclear waste (ask japan about that, they're pretty mad at the us and canada for shipping our old packs back to them.) People think zero emissions in electric mode and completely forget that it's a whole system, no just whats going on when you drive.

Hybrids doesn't mean batteries as a given fact, remember that flying wheels are a reality right now for industrial plants, and in less than a year they will be adopted on large vehicles, like a bus.
Also, while with the present technology batteries are indeed a double edged sword, many of the are focused in achieving a good electric only range, while much less of that would be required given this mode would be used only in downtowns and the likes.
Finally, diesels aren't more expensive, it's a common thing they managed to convince us. it may have been true in 1998 with the first common rail engines (actually one of the first engines, the 1.9 JTD by Fiat, was available on the 156 for precisely 20.546 € (not much really for a brand new technology), while the base (and old) 1.6 liter petrol engine I think it was for sale at 18.000 €.
Right now the costs of those engines are basically the same of their petrol counterparts, but automakers still pretends to apply an higher price, knowing that we are both used to pay more for a diesel and and interested in the better mileage, thinking we are going to save back the extra money, which is true only if you drive at least say 25.000 km per year or more.

[Ferrer]

Right now the costs of those engines are basically the same of their petrol counterparts, but automakers still pretends to apply an higher price, knowing that we are both used to pay more for a diesel and and interested in the better mileage, thinking we are going to save back the extra money, which is true only if you drive at least say 25.000 km per year or more.
In some cases they even cost the same. I remember when we bought the 118d, it cost exactly the same as the 118i. Don't know if it still does though.

[henk4]

In some cases they even cost the same. I remember when we bought the 118d, it cost exactly the same as the 118i. Don't know if it still does though.
remember there is a difference between production costs and selling prices....

[Ferrer]

remember there is a difference between production costs and selling prices....
Maybe the margins are thinner on the diesels, but I'm sure BMWs relies on other margins to get massive benefits. Like making you pay extra for pretty much anything.

They mustn't have won much with our car though...

[LeonOfTheDead]

Considering the profits of premium brands weren't lower recently (meaning the pre-crisis years) and considering they were selling mainly diesel cars, yes, the margin is there, proud and loud.
Surely for a brand new company designing a standard petrol car is easier, less components, more space in the engine bay, smaller gearbox and drivetrain components and so on.
Modern petrol engines are as much complicated as diesels though, especially if we are to consider turbocharged units. The nice thing about diesels is that much of the job is done by suppliers like Bosh, while petrol engine are more in-house developed.
This like of investment from the companies into diesel stuff should indicate that they knew it wasn't going to last much, so giving all the investments to basically one main supplier (which will also benefit from sharing the costs on much more parts sold) was a more sensible idea.
That at first explained the major costs, it was a new technology, and outsourced. Now the evolution of the diesel is relying on minor updates and smaller parts, which also happen to cost less to develop. Hence why the costs are now lower, while petrol engines are receiving much more attention (so costs).
Take Fiat, last time they did a turbocharged engine was the 15 years ago or so, and it was something pretty ordinary even back in the days, albeit 100% effective.
Now they are putting on the market almost only turbocharged engine, they are moving towards eliminating camshafts (not correct, a cam is still present) for the intake valves and many other things. That costs, a lot.

[4wheelsonline]

It all comes down to the way you use the car.

The truth is that from a financial point of view, the Diesel is superior to the Petrol engine because of its accessible power band and the better fuel economy for a given power figure.

Many argue for the emotional qualities of the petrol engine, like the higher revving character and the sound. True, but this realistically applies only to sports cars. If someone buys a Mondeo 3.0 V6, then he is wasting his petrol over a bad chassis.

Conclusion: 80% of the population's driving style is better suited to the Diesel, but for some reason some of them choose petrol engines.

Yes. I definitely agree diesel is more cheaper than petrol products.:p

[Ferrer]

Alright I was trying to find the post where Damiano said we tend to drive petrol powered cars more aggresively but I can't. :p

And it's true, having driven the Delta for some weeks now, I tend to rev it higher than the BMW. It's not like this means redlining or going flat out eveywhere. Just more revs than diesel driving.

I think it's because it's more enjoyable, and more rewarding. Altough this shows on the fuel consumption. I doubt I'll go past 500km in this tank. But we'll see.

[pimento]

I'da thunk a petrol car would need more revs to exploit the power band than a diesel car anyway.. but the only diesels I've driven have been utes or small trucks.

[Ferrer]

I'da thunk a petrol car would need more revs to exploit the power band than a diesel car anyway.. but the only diesels I've driven have been utes or small trucks.
True. But if you don't need or want to go very fast you can also drive a petrol car without many revs. What I meant is that I find myself revving the Lancia higher than I could given the speed and the driving conditions.

[LeonOfTheDead]

True. But if you don't need or want to go very fast you can also drive a petrol car without many revs. What I meant is that I find myself revving the Lancia higher than I could given the speed and the driving conditions.

which is what I originally meant.:)

[henk4]

True. But if you don't need or want to go very fast you can also drive a petrol car without many revs. What I meant is that I find myself revving the Lancia higher than I could given the speed and the driving conditions.
the fun thing is that you can drive a diesel relatively (very) fast without using too many revs....

[f6fhellcat13]

Or a low-powered gasoline car relatively slowly (legally) while still revving it excessively and having fun and a "more involved" driving experience in the process.

I have not driven a diesel car, so I really cannot comment accurately, but the way they're made out, I would imagine the sensation of speed is lacking.

[henk4]

I have not driven a diesel car, so I really cannot comment accurately, but the way they're made out, I would imagine the sensation of speed is lacking.
your invited to come over and try for yourself.

[f6fhellcat13]

My only encounter with compression ignition was in a rattly old moving truck, which I think is not a fair way to judge diesel passenger cars.

[LeonOfTheDead]

Or a low-powered gasoline car relatively slowly (legally) while still revving it excessively and having fun and a "more involved" driving experience in the process.

I have not driven a diesel car, so I really cannot comment accurately, but the way they're made out, I would imagine the sensation of speed is lacking.

I actually think they seem faster.
They are louder, and the way the torque quickly becomes available let you think you're about to fly. Also, having a turbo helps moving the car quickly while with naturally aspirated petrol cars it seems to get more time. It's all relative.

Certain petrol cars used to have the power curve a bit too vertical to get really involved in the driving, as with old turbocharged cars, but without the kick. Fortunately it isn't so anymore, even without using larger engines.

That said, the car which impressed me the most for its speed and acceleration was the old Fiat Panda, with the 900 cc engine.
The car isn't fast by any mean, but if you think you're going that fast in a tuna's can, well, that's really fast.

[lightweight]

I actually think they seem faster. It's all relative.

The way I see it is that Diesels offer effortless performance in the way that a Rolls does. The V12, although petrol powered, is extremely torquey at low revs and virtually silent.

The Diesels offer the same kind of sensation. Travelling on the motorway at sixth gear on 1000 rpm, flooring the throttle and feeling a relentless silent push forward. Given the long gearing, the push will go on for pretty long...

Of course, this sensation disappears at the twisty bits..

[LeonOfTheDead]

The way I see it is that Diesels offer effortless performance in the way that a Rolls does. The V12, although petrol powered, is extremely torquey at low revs and virtually silent.

The Diesels offer the same kind of sensation. Travelling on the motorway at sixth gear on 1000 rpm, flooring the throttle and feeling a relentless silent push forward. Given the long gearing, the push will go on for pretty long...

Of course, this sensation disappears at the twisty bits..

So I drive a Phantom, good to know that :D

Honestly, if you don't have a twin turbo engine, flooring the throttle at 1.000 rpm would result in..............nothing.
Behind 1.500/1.700 rpm single turbo engines are pretty dead, and if you have a VGT equipped engine, flooring would result in an even larger lag as the turbine would try to provide you the higher boost which incidentaly coincides with the major lag.
The best way would be slowly flooring the throttle so to continuously adjust the geometry of the turbine.

[Ferrer]

Or a low-powered gasoline car relatively slowly (legally) while still revving it excessively and having fun and a "more involved" driving experience in the process.

I have not driven a diesel car, so I really cannot comment accurately, but the way they're made out, I would imagine the sensation of speed is lacking.
It's not the speed that's lacking. Diesels have a fairly narrow powerband, but as long as you use the lever between the seats you can make progress fairly rapidly.

The way I see it is that Diesels offer effortless performance in the way that a Rolls does. The V12, although petrol powered, is extremely torquey at low revs and virtually silent.

The Diesels offer the same kind of sensation. Travelling on the motorway at sixth gear on 1000 rpm, flooring the throttle and feeling a relentless silent push forward. Given the long gearing, the push will go on for pretty long...

Of course, this sensation disappears at the twisty bits..
I personally think that this isn't the case, at least with single turbo diesels (which are the ones I've driven). I'd say that the Lancia has better in gear acceleration than the BMW, at least in terms of sensations. However the BMW carries much longer gearing, so maybe it isn't a very fair comparison.

By the way, first tank in the Lancia I recorded and thing aren't looking good as far as economy is concerned... I'll put the results in the fuel economy thread.

[group c n b man]

Diesel is far superior around town because of drivability and also is very punchy in the mid ranges. However I agree that the powerband is very narrow. Below 2000rpm nothing happens and above 4000rpm a similar story. You need to shift a lot when trying to drive a diesel hard due to this. There's just no point in hanging on to every gear until the red line because it runs out of steam before then. It doesn't sound great either. Much more fun is to be had with petrol in this regard.

[henk4]

Diesel is far superior around town because of drivability and also is very punchy in the mid ranges. However I agree that the powerband is very narrow. Below 2000rpm nothing happens and above 4000rpm a similar story. You need to shift a lot when trying to drive a diesel hard due to this. There's just no point in hanging on to every gear until the red line because it runs out of steam before then. It doesn't sound great either. Much more fun is to be had with petrol in this regard.
so a gearbox that is a joy to play with and the low end power of a diesel would be the ideal combination....and what is the point of permanent redlining anyway....

[jcp123]

So it all depends on who's driving? A low-rev guy like me who shortshifts would be better served by a diesel, while someone who prefers revving might choose a petrol engine?

[Ferrer]

So it all depends on who's driving? A low-rev guy like me who shortshifts would be better served by a diesel, while someone who prefers revving might choose a petrol engine?
Not necessarily. There are plenty of petrol engines with different characteristics and the same can be said for diesels. So it really depends on what you want and you need.

And by the way, redlining a petrol engine (sometimes) is fun.

[lightweight]

so a gearbox that is a joy to play with and the low end power of a diesel would be the ideal combination....and what is the point of permanent redlining anyway....

Works for me:)

[nota]

Honestly, if you don't have a twin turbo engine, flooring the throttle at 1.000 rpm would result in..............nothing.
Behind 1.500/1.700 rpm single turbo engines are pretty dead, ...
Its interesting to compare the torque graph of this single-turbo Falcon 4.0 litre 6cyl (FPV F6) to the output of the non-turbo version of the same engine which requires 2,500 rpm to produces 383 Nn.

The turbo variant needs less than half the revs (1,200 rpm) to equal the maximum output of the non-turbo, and btw has been widely praised for having virtually no lag.

[Ferrer]

Its interesting to compare the torque graph of this single-turbo Falcon 4.0 litre 6cyl (FPV F6) to the output of the non-turbo version of the same engine which requires 2,500 rpm to produces 383 Nn.

The turbo variant needs less than half the revs (1,200 rpm) to equal the maximum output of the non-turbo, and btw has been widely praised for having virtually no lag.
He was refering to diesels. And I concur. Below 2000rpm there's almost nothing. Petrol engines are usually a different story.

[nota]

He was refering to diesels. And I concur. Below 2000rpm there's almost nothing. Petrol engines are usually a different story.
Does this diesel maxim also apply to single-turbo engines in small to large trucks, 4x4s etc?

[lightweight]

Does this diesel maxim also apply to single-turbo engines in small to large trucks, 4x4s etc?

The engine powerband is irrelevant of the chassis.

[henk4]

The engine powerband is irrelevant of the chassis.

I think it was meant whether (turbo) diesel engines in small utility vehicles have the same characteristics, and I think the answer is no as they have been mostly mapped to produce more torque at low revs, at the expense of a lower max BHP output at higher revs. My 8x6 armoured car that I drove when in the army (40 years ago...) was a single turbo diesel engine, maximum revs 2200, but no lag at all....
Today the situation is still the same.

[nota]

The engine powerband is irrelevant of the chassis.
So those single-turbo diesels (as seen in Japanese pickups and 4x4s eg) show no increase in torque at lower rpms over their non-turbo variants?

Is that the reality?

[LeonOfTheDead]

Its interesting to compare the torque graph of this single-turbo Falcon 4.0 litre 6cyl (FPV F6) to the output of the non-turbo version of the same engine which requires 2,500 rpm to produces 383 Nn.

The turbo variant needs less than half the revs (1,200 rpm) to equal the maximum output of the non-turbo, and btw has been widely praised for having virtually no lag.

See this:


He was refering to diesels. And I concur. Below 2000rpm there's almost nothing. Petrol engines are usually a different story.


Does this diesel maxim also apply to single-turbo engines in small to large trucks, 4x4s etc?

That depends on the size, but as Henk wrote, those kind of engine are built to behave differently, with lower redlines, and more low end torque.

I'm talking about diesel engine, specifically single turbo engine up to 3.000 cc of displacement.
Of the many diesel cars we had, all around 2.0 liters, none of them were capable of quick responses under 1.500/1.700 even if it isn't a problem when you're in gear. If that's not the case, you'll have to wait a while before of something happening.
That's the case even with a 6 speed gearbox and VGT, slowly stepping on the throttle.

[Ferrer]

So those single-turbo diesels (as seen in Japanese pickups and 4x4s eg) show no increase in torque at lower rpms over their non-turbo variants?

Is that the reality?
I doubt it. But the problem isn't absolute numbers but relative perfomance. All diesels I've driven show the smae sluggishness at low revs.

[Ferrer]

That's interesting (in Italian).

Il declino del diesel (http://www.automobilismo.it/edisport/automobilismo/AutoR2.nsf/gd/Il-declino-del-diesel-1-Introduzione)

[henk4]

That's interesting (in Italian).

Il declino del diesel (http://www.automobilismo.it/edisport/automobilismo/AutoR2.nsf/gd/Il-declino-del-diesel-1-Introduzione)
I suppose that is the graph for Europe as a whole, or which countries are included? In Holland there is certainly a decline, mainly because of the popularity of the small cars like the PSA/Toyota triplet. Given our tax system, which put an significant additional purchase and road tax on diesel engined cars, in combination with a much lower tax on diesel than on petrol. This results in a business case where you have to drive a diesel a lot to arrive at break even costs with a petrol engined car.
Secondly, there is a decline in the purchase of company/lease cars, which to a large extent are diesels too.
So what we see is an increased share of small petrol engined cars, certainly inspired by the current economic situation.

[LeonOfTheDead]

Yes I agree, even if I myself predict a decline of sales for diesel engines cars, I don't see it happenings that soon and at a so large extent.
We have also to consider that a lot of large cars and SUVs, mostly bought out of a luxury need rather than actual necessity, were diesel powered.
If you want to show off a BMW X6, it's more than likely that you'll opt for the diesel, being scared to sustain the fuel consumption of the petrol versions. After all you don't even know about cars if you wanted to buy that thing, let alone if you understand fuel consumption.
So now you're broke, and you need a smaller show-off thingy, and since the giant SUV look is gone, you're going probably to buy something more performance oriented, like a roadster or coupe, possibly even with a petrol engine, like with an Audi TT (still to see a diesel engined model on the road), or the Z4.

[henk4]

Yes I agree, even if I myself predict a decline of sales for diesel engines cars, I don't see it happenings that soon and at a so large extent.
We have also to consider that a lot of large cars and SUVs, mostly bought out of a luxury need rather than actual necessity, were diesel powered.
If you want to show off a BMW X6, it's more than likely that you'll opt for the diesel, being scared to sustain the fuel consumption of the petrol versions. After all you don't even know about cars if you wanted to buy that thing, let alone if you understand fuel consumption.
So now you're broke, and you need a smaller show-off thingy, and since the giant SUV look is gone, you're going probably to buy something more performance oriented, like a roadster or coupe, possibly even with a petrol engine, like with an Audi TT (still to see a diesel engined model on the road), or the Z4.

I think "large cars and SUVs" only form a small percentage of the overall European market. What is important is the "Golf" class, where the majority of the cars delivered might still be diesel powered. (I don't have figures at hand, so I might be wrong). Most cars below the Golf class are, at least in Holland, petrol powered, as an example, the PSA Twins are not even available over here as the diesel tax rules make them far too expensive.
The C-D Segments (Passat/C5/Laguna) is predominantly diesel powered too. The decline of sales in those segments may have contributed much more to the decline in diesel share than the end of the SUV boom.

[LeonOfTheDead]

I think all premium cars, from the Passat/C5/159 (no Laguna here) are all diesels though, and they aren't few.
Sedans like those quoted are basically all diesels, correct, smaller cars, like the GOlf an the Bravo are probably 60/70% diesel but with new petrol engines things are changing a bit (see Albert getting the petrol Delta). Beyond thosem with the Punto and even smaller cars, it's the opposite situation, more petrol than diesel cars.

[henk4]

I think all premium cars, from the Passat/C5/159 (no Laguna here) are all diesels though, and they aren't few.
Sedans like those quoted are basically all diesels, correct, smaller cars, like the GOlf an the Bravo are probably 60/70% diesel but with new petrol engines things are changing a bit (see Albert getting the petrol Delta). Beyond thosem with the Punto and even smaller cars, it's the opposite situation, more petrol than diesel cars.
Large cars for me are the S-Type, the 7-Series and the A8 etc. What you mention as premium cars are considered "middle class" in Holland (as well as in Germany). So large cars are not a considerable part of the market.

[LeonOfTheDead]

I see, ok, I meant 5-Series, E Klasse, A6, S-type (it isn't as large as an A8, isn't it?), as well as X5, ML, Q7, so basically everything with a price tag (here) from 40 to 60.000 €.
They aren't surely the major part of the market, but there are quite a few of them on the streets, and all diesels.
This kind of cars should have been influenced more than cheaper ones by the situation, that's my reasoning.

[henk4]

I see, ok, I meant 5-Series, E Klasse, A6, S-type (it isn't as large as an A8, isn't it?), as well as X5, ML, Q7, so basically everything with a price tag (here) from 40 to 60.000 €.
They aren't surely the major part of the market, but there are quite a few of them on the streets, and all diesels.
This kind of cars should have been influenced more than cheaper ones by the situation, that's my reasoning.
S-Type as in Mercedes S-Type, which is A8 size...
what you show is the E-Segment, also known as upper middle class....

[Ferrer]

S-Type as in Mercedes S-Type, which is A8 size...
what you show is the E-Segment, also known as upper middle class....
He probably meant the Jag S-Type now replaced by the XF.

I don't think the decline is that signifcant yet, IIRC (can't remember the exact figures) the article says diesels have gone from a 54% market share in 2007 to a 45% now in 2009.

I think Pieter does have a point with small cars being predominantly switched over to small modern petrol engines. Especially if you don't do a lot of kilometres anually they make a lot of sense.

I guess people are starting to realise that and they are acting accordingly. I've noticed an increase of petrol powered B and C segment cars here, which are the ones that dominate the market. Even some D and E segment cars start to have petrol engine in them, something that was very rare a year os so ago.

[LeonOfTheDead]

With less money in the wallet, you're more prone to buy what's cheaper, not only cheaper to run. The additional cost of a diesel car (amplified in Holland it seems) may have a role.

[Ferrer]

With less money in the wallet, you're more prone to buy what's cheaper, not only cheaper to run. The additional cost of a diesel car (amplified in Holland it seems) may have a role.
Also diesels may not make financial sense if you drive mostly in the city and not very long distances.

[LeonOfTheDead]

Also diesels may not make financial sense if you drive mostly in the city and not very long distances.

Surely, and perhaps having less money to waste helped some people to realize this.

[henk4]

Also diesels may not make financial sense if you drive mostly in the city and not very long distances.
I think if you drive 40000 km in the city, the financial advantages of the diesel may weigh up against a petrol car. Both though will loose out against a hybrid under the same conditions.

[Ferrer]

I think if you drive 40000 km in the city, the financial advantages of the diesel may weigh up against a petrol car. Both though will loose out against a hybrid under the same conditions.
Are you thinking of taxis? ;)

Indeed. But if you like 10 to 15 thousand kilometres you are probably better off with one those modern turbocharged petrols.

[LeonOfTheDead]

Are you thinking of taxis? ;)

Indeed. But if you like 10 to 15 thousand kilometres you are probably better off with one those modern turbocharged petrols.

I guess even without the turbo.

[lightweight]

This is indeed a very interesting conversation, although arguments are expressed in a qualitative manner. I was trying myself to quantify all this information, but I need your help on something:

Does anybody know where to find engine prices (that's right how much an engine costs to buy). If someone has a rough estimation it is welcome, also. Doesn't need to be precise to the cent. +/- 10% is fine.

The engines I would be interested would be a 100 bhp Diesel and its Petrol equivalent (if it's from other manufacturer, it's OK). If someone has the above data for a 200 bhp and 300 bhp, feel free to share!:)

EDIT: Even a rough estimate would do e.g. (Equivalent Diesels cost 20% more than Petrol)

[Ferrer]

This is indeed a very interesting conversation, although arguments are expressed in a qualitative manner. I was trying myself to quantify all this information, but I need your help on something:

Does anybody know where to find engine prices (that's right how much an engine costs to buy). If someone has a rough estimation it is welcome, also. Doesn't need to be precise to the cent. +/- 10% is fine.

The engines I would be interested would be a 100 bhp Diesel and its Petrol equivalent (if it's from other manufacturer, it's OK). If someone has the above data for a 200 bhp and 300 bhp, feel free to share!:)

EDIT: Even a rough estimate would do e.g. (Equivalent Diesels cost 20% more than Petrol)
I think that the price for an engine will be difficult to find, but we could compare whole cars. Like the Clio TCe (101bhp) and the Clio 1.5 dCi (105bhp). Altough it'll be difficult to be very precise if we don't know the running costs.

[LeonOfTheDead]

I don't have a specific clue on that, but if you consider the same car has a 1.500/3.000 price difference, depending on the specific car, if bought with a petrol (cheaper) or diesel (more expensive) engine, you have the first data to consider.
That would be the additional cost to install the diesel engine itself and different parts (like a stronger gearbox/clutch) required by that engine.

[lightweight]

We could compare whole cars. Like the Clio TCe (101bhp) and the Clio 1.5 dCi (105bhp).

Good point. I will use this example, as a tribute to your contribution:D


Altough it'll be difficult to be very precise if we don't know the running costs.

True, but still, let's make the comparison excluding the service & maintenance costs. They are very difficult to access anyway.


I don't have a specific clue on that, but if you consider the same car has a 1.500/3.000 price difference, depending on the specific car, if bought with a petrol (cheaper) or diesel (more expensive) engine, you have the first data to consider.
That would be the additional cost to install the diesel engine itself and different parts (like a stronger gearbox/clutch) required by that engine.

For that reason I will take Ferrer's advice and compare the equivalent car as a whole.

I need an extra bit of advice, though. How do I convert a set of Excel cells or an Excel graph into a JPEG?:)

Thanks in advance!

[Ferrer]

I need an extra bit of advice, though. How do I convert a set of Excel cells or an Excel graph into a JPEG?:)

Thanks in advance!
Print Screen?

[lightweight]

Print Screen?

Did it with Photoshop:)

PURPOSE
Determine when it is preferable to own a Diesel or a Petrol cost-wise, with a quantitative analysis. It is widely accepted that Petrol cars are cheaper to buy, but fuel bills are bigger. After a certain point, Diesel becomes cheaper to own.

METHOD

Compare 3 different sets of cars over 3 different power levels (100, 200, 300 bhp), in order to determine the mileage threshold after which it is cheaper to run on Diesel


Set 1 (around 100 bhp): Clio Privilège dCi 106 (Diesel) vs Clio Privilège 1.2 Turbo 100 (Petrol)
Set 2 (around 200 bhp): BMW 320d SE (Diesel) vs BMW 320i SE (Petrol)
Set 3 (around 300 bhp): BMW 335d SE (Diesel) vs BMW 330i SE (Petrol)

LIMITATIONS
All costs are official figures for the UK Market, as of 18/10/2009, in pounds sterling
Fuel Consumption figures are manufacturer claims on Combined Fuel Cycle in Imperial MPG, converted in US MPG and l/100km
As obtaining cost data for engines alone is rather difficult, the comparison is made on the vehicle as a whole, hence the "Cost for Respective Mileage (THX Ferrer)
Service & maintenance costs are rather difficult to find, so this factor is left out, although it would help clarify matters even more
Real life fuel consumption is different from the official manufacturer's claims, even more so when driving fast, but since there is not a widely accepted measurement standard between "slow" and "fast" driving, I will stick to the officially published figures. They give a like to like basis for comparison

CONCLUSIONS
The Clios break even (not break down :D)at around 135.000 km
The 2 Litre BMWs break even at around 115.000 km
The 3 Litre BMWs break even at a staggering 675.000 km
After the distance mentioned above, the Diesel is cheaper to run
The BMW 335d SE is very thirsty. BMW, in its attempt to make a sporty Diesel, ruined its fuel economy. This shows that manufacturers have some way to go in making sporty Diesel engines
The Clio Diesel costs half the money to run compared to the BMW 3 litre Petrol at around 800,000 km. It seems that the BMW is cheap to run after all. I would expect the Clio to be MUCH cheaper
I would never have thought that the cost of running a Clio (excluding insurance costs and service & maintenance) would be around £60,000 for 800,000 km (around ten years of ownership)

SOURCES

Fuel consumption conversions (http://en.wikipedia.org/wiki/Miles_per_gallon#To_MPG_.28Imp.29)
Fuel prices (http://www.theaa.com/motoring_advice/fuel/index.html)
Renault Clio Data (http://www.renault.co.uk/cars/model/new-clio/pricesandspecs.aspx)
BMW 320d SE (http://www.bmw.co.uk/bmwuk/pricesandspecifications_technical_specs/0,,1156_160173812__bs-Mw%3D%3D@bb-Q1AwNg%3D%3D@bm-V0QxMg%3D%3D,00.html?tab=technicalSpec)
BMW 320i SE Data (http://www.bmw.co.uk/bmwuk/pricesandspecifications_technical_specs/0,,1156_160173812__bs-Mw%3D%3D@bb-Q1AwNg%3D%3D@bm-V0E3Mg%3D%3D,00.html?tab=technicalSpec)
BMW 335d SE Data (http://www.bmw.co.uk/bmwuk/pricesandspecifications_technical_specs/0,,1156_160173812__bs-Mw%3D%3D@bb-Q1AwNg%3D%3D@bm-V0Q3Mg%3D%3D,00.html?tab=technicalSpec)
BMW 330i SE Data (http://www.bmw.co.uk/bmwuk/pricesandspecifications_technical_specs/0,,1156_160173812__bs-Mw%3D%3D@bb-Q1AwNg%3D%3D@bm-WjNEQw%3D%3D,00.html?tab=technicalSpec)

[Ferrer]

Excellent post lightweight.

We can also see that if we estimate a 6 year life for the cars, you'd have to do 22.500km a year in the Clios, 19.200km yearly in the 4 cylinder BMWs and 112.500km anually in the 6 cylinder BMWs for the diesel to make economic sense. In a general sense we could argue that unless you do 20.000km a year or more, sticking to petrol proves to be better financially.

I wonder how many people that do 20.000km or less every year are stuck with a diesel because "it costs less".

[lightweight]

It all depends on how much you keep the car before selling it.

The analysis would be thorough if one had access to service & maintenance costs data, as well as the depreciation rate of the car.

As this analysis takes into consideration the prices of the cars when new, the break even threshold would favour used Diesels over used Petrol cars, i.e. you must drive less km in order to break even.

Also, if you are a student and your parents buy you a car, get a Diesel, save money on gas and get drunk more :)

[LeonOfTheDead]

Generally diesel cars are more expensive on the second hand market, just because people still think they are objectively cheaper to run. On the other hand maintenance is a bit more expensive, as for example at 120.000 km or so, depending on the specific car, you should regenerate the particulate filter, and also because there are still a buch of stealerships pretending they (diesel cars) need more maintenance and more expensive one too.
I think smaller diesel cars tend to need a bit more attention than a petrol car though. Just comparing how badly certain city cars are used with no mechanical issues, while if they are diesels, they tend to have alternator's problems, the battery is often down, starting sparks are always ignored (which isn't good at all) and so on.

It isn't the case anymore basically, but over here the insurance cost is based also on the displacement, and diesel engines tended to be larger than their power wise similar petrol counterparts.

[lightweight]

Generally diesel cars are more expensive on the second hand market

True, but what matters is the price difference between New Diesel vs New Petrol and Used Diesel vs Used Petrol. It most likely that the Used Diesel vs Used Petrol difference is going to be smaller in terms of money.

I fully accept that the maintenance costs for Diesels are pretty high as the mileage goes up. Sad, we don't have any data to make a fair somparison and decide:(

[Ferrer]

True, but what matters is the price difference between New Diesel vs New Petrol and Used Diesel vs Used Petrol. It most likely that the Used Diesel vs Used Petrol difference is going to be smaller in terms of money.
I don't think that's actually the case. I'd say that the diesel's depreciation is better than petrol's and that the difference is maintained at least maybe in relative terms. I'll check some used car websites see if that's the case.

[Ferrer]

Alright. Since in 2007 the BMW 118i and the BMW 118d both had 2 litre engines that produced 143bhp and had the same list price I used those as the yardstick. First thing you notice is that there are four times more diesel engined cars on sale than there are petrol cars.

Diesel

I used BMW Certified cars. Cars vary in condition and equipment, but have in general higher mileage than their petrol counterparts. There are 17 BMW Certified second hand 118d on sale.

BMW Serie 1 de segunda mano. Coches BMW Serie 1 de ocasión en venta (http://www.coches.net/coches-de-ocasion.aspx?pg=2&MakeId=7&ModelId=539&MinYear=2007&MaxYear=2007&Version=118d&ext=1&or=-1&fi=SortDate)

BMW Serie 1 de segunda mano. Coches BMW Serie 1 de ocasión en venta (http://www.coches.net/coches-de-ocasion.aspx?pg=3&MakeId=7&ModelId=539&MinYear=2007&MaxYear=2007&Version=118d&ext=1&or=-1&fi=SortDate)

The average price for a 2007 118d is 20.185€.

Petrol

Again I used BMW Certified cars only to try and minimise the variation of conditions. There are only 7 officially certified 118is, as opposed to the 17 118ds.

BMW Serie 1 de segunda mano. Coches BMW Serie 1 de ocasión en venta (http://www.coches.net/coches-de-ocasion.aspx?or=0&fi=SortDate&MakeId=7&ModelId=539&tops=1&SearchOrigin=2)

The average price for a 2007 118i is 19.287€.

So it would seem that yes, diesels do depreciate less than equivalent petrols.

[lightweight]

Since in 2007 the BMW 118i and the BMW 118d both had 2 litre engines that produced 143bhp and had the same list price I used those as the yardstick.

Hmmm, seems odd that they had the same price. It seems then that Diesel is a non-brainer in terms of economic gains like the ones described on my analysis! But then this explains that "First thing you notice is that there are four times more diesel engined cars on sale than there are petrol cars".

Overall, interesting set of data. What would be interesting would be to compare the average price demonstrated above with the price of the cars when new and then express it as a percentage.

Also, as a used car buyer, when buying a Diesel, you begin with an average "deficit" of 898 € (20.185 - 19.287). The miles that you have to do in order to break even is a lot less than the ones you have to do in the 320 example posted above.

I would presume that this data is from Spain. One extra factor is the difference in the different markets of each country. The pricing policy for example between Diesel and petrol varies from country to coutry. Also fuel prices.

[henk4]

LIMITATIONS
All costs are official figures for the UK Market, as of 18/10/2009, in pounds sterling

which is quite a distortion.

Perhaps carrying out the same comparison using data from this link might produce totally different results.

Carpooling with Karzoo - Petrol prices in Europe (http://www.karzoo.eu/en/petrol-prices)

(Prices in Holland are for some reasons not included, but regular 95 is about 1.36 and diesel about 1.02. (prices can differ by at least 7 or 8 cents per liter depending on the fuel station, motorways are the highest).
Not trying to down play your calculations, but I want to prevent that your figures will be seen as the only truth...;)

[henk4]

Alright. Since in 2007 the BMW 118i and the BMW 118d both had 2 litre engines that produced 143bhp and had the same list price I used those as the yardstick. First thing you notice is that there are four times more diesel engined cars on sale than there are petrol cars.

Diesel

I used BMW Certified cars. Cars vary in condition and equipment, but have in general higher mileage than their petrol counterparts. There are 17 BMW Certified second hand 118d on sale.

BMW Serie 1 de segunda mano. Coches BMW Serie 1 de ocasión en venta (http://www.coches.net/coches-de-ocasion.aspx?pg=2&MakeId=7&ModelId=539&MinYear=2007&MaxYear=2007&Version=118d&ext=1&or=-1&fi=SortDate)

BMW Serie 1 de segunda mano. Coches BMW Serie 1 de ocasión en venta (http://www.coches.net/coches-de-ocasion.aspx?pg=3&MakeId=7&ModelId=539&MinYear=2007&MaxYear=2007&Version=118d&ext=1&or=-1&fi=SortDate)

The average price for a 2007 118d is 20.185€.

Petrol

Again I used BMW Certified cars only to try and minimise the variation of conditions. There are only 7 officially certified 118is, as opposed to the 17 118ds.

BMW Serie 1 de segunda mano. Coches BMW Serie 1 de ocasión en venta (http://www.coches.net/coches-de-ocasion.aspx?or=0&fi=SortDate&MakeId=7&ModelId=539&tops=1&SearchOrigin=2)

The average price for a 2007 118i is 19.287€.

So it would seem that yes, diesels do depreciate less than equivalent petrols.

Do petrol BMW's still require 98 Super Plus fuel?

[Ferrer]

Hmmm, seems odd that they had the same price. It seems then that Diesel is a non-brainer in terms of economic gains like the ones described on my analysis! But then this explains that "First thing you notice is that there are four times more diesel engined cars on sale than there are petrol cars".

Overall, interesting set of data. What would be interesting would be to compare the average price demonstrated above with the price of the cars when new and then express it as a percentage.

Also, as a used car buyer, when buying a Diesel, you begin with an average "deficit" of 898 € (20.185 - 19.287). The miles that you have to do in order to break even is a lot less than the ones you have to do in the 320 example posted above.

I would presume that this data is from Spain. One extra factor is the difference in the different markets of each country. The pricing policy for example between Diesel and petrol varies from country to coutry. Also fuel prices.
I remember they were the same because when we bought the BMW we looked at several models, (116i, 118i, 118d and 120d) and the "18s" cost exactly the same. It isn't the case anymore though, now the 118i is 200€ cheaper than the 118d.

Do petrol BMW's still require 98 Super Plus fuel?
Yes, they do. (Well at least in 2007)

[lightweight]

Not trying to down play your calculations, but I want to prevent that your figures will be seen as the only truth...;)

Hmm, yes there is quite a difference. I guess all monetary figures are susceptible to variations, according to which source you take into consideration.

First and foremost, the variable that WILL change results no matter what, is the date. Petrol prices change from day to day.

Taking this into consideration and taking into account that I tried to narrow down the search to the UK, I used the manufacturer suggested retail price for the UK for the cars and the AA fuel prices which is doing research in the UK only, so I thought that the data would be more representative.

May I note that the prices in my analysis are Pounds sterling and not Euros. The prices from Karzoo.eu, if converted to Pounds Sterling are £1,098 for the 95 Octane, which is a 3% difference. Same for Diesel. Pretty acceptable difference for a forum discussion:)

But, the only thing that changes after all is the km that the break even is achieved:


Clio: 125.000 km (instead of 135.000 km)
BMW 320: 115.000 km (same as before)
BMW 330: 650.000 km (instead of 675.000 km)


Which only shows that more expensive fuel makes even more sense for Diesels! But I guess we don't need a report to make that conclusion:D

[henk4]

Hmm, yes there is quite a difference. I guess all monetary figures are susceptible to variations, according to which source you take into consideration.

First and foremost, the variable that WILL change results no matter what, is the date. Petrol prices change from day to day.

Taking this into consideration and taking into account that I tried to narrow down the search to the UK, I used the manufacturer suggested retail price for the UK for the cars and the AA fuel prices which is doing research in the UK only, so I thought that the data would be more representative.

May I note that the prices in my analysis are Pounds sterling and not Euros. The prices from Karzoo.eu, if converted to Pounds Sterling are £1,098 for the 95 Octane, which is a 3% difference. Same for Diesel. Pretty acceptable difference for a forum discussion:)

But, the only thing that changes after all is the km that the break even is achieved:


Clio: 125.000 km (instead of 135.000 km)
BMW 320: 115.000 km (same as before)
BMW 330: 650.000 km (instead of 675.000 km)


Which only shows that more expensive fuel makes even more sense for Diesels! But I guess we don't need a report to make that conclusion:D

The point I was trying to make was that these calculations will greatly differ for each country. ;) and what is valid for the UK may in no way be the case in Holland or Germany. I have seen French and German magazines where they made similar calculations for the break even point, and in some cases diesel was cheaper from km zero....

[Ferrer]

The point I was trying to make was that these calculations will greatly differ for each country. ;) and what is valid for the UK may in no way be the case in Holland or Germany. I have seen French and German magazines where they made similar calculations for the break even point, and in some cases diesel was cheaper from km zero....
That could only happen if the cars cost the same, couldn't it?

[henk4]

That could only happen if the cars cost the same, couldn't it?

could also relate to taxes and insurance premiums.....

[crug75hid]

All the leading car manufacturers are making the both versions as well as petrol and diesel, choice is depends on the purpose of the usage.