Pushrod or OHC

[Matra et Alpine]

Originally Posted by Slicks

Sorry to break it to you but even the people who hate Bush here dont think he was in it for oil, especially since the gas prices are still raising, dont you think they would be dropping?

2 possible reasons - it's not workign out how GWB thought it would - afer all I didn't hear him ask the American voters to commit to provide larged fighting force STILL engaged in street guerilla warfare for the next 5+ years

That would make a diesel less efficient(shortening gears), and their all about effiency right? And you were talking about performance diesels too. If they want to perform, they should beable to meet what petrol can put out.

They are in cases now that compact 6 and more speed boxes with fsat pre-elector shifts are about.
WHY woudl it make it "less efficient" ? Wider torque does not NEED the designer to change the gears, they can retain the gears and give better drivability. THAT's why wider bands are wanted, to give the driver better options.

[Slicks]

Originally Posted by henk4

Again you come up with the marketing argument and that we are brainwashed in Europe. Earlier on I replied you that the average carowner in Europe really cares about his valve drive. If you are talking about marketing, may be the word "hemi" is a pure marketing concept as the old engine still is in the back of many american's mind.

Its not just in Europe.
BIGNO! "HEMI" just like "hightech" is a marketing technique.

When I quoted the mileage of the 300C I gave you the source which was a road test and not a standardised EPA system (we also have an ECE mileage system here in Europe which tends to be highly optimistic) and I compared the test results (the total fuel consumption of the car during all testing activites including accelaration measurements and (ungoverned) top speed drives) with the test results by the same authoritative magazine for the BMW 7-series and the Mercedes E500. These cars can get less more than 10 km out of litre if they are feathered, the 300C managed 9 at best.

I use EPA figures because everyone drives differently, there are different elevations, temperatures, traffic etc. Using EPA cancels out most of that, and gives you a good figure. So far, every car Ive kept mpg on match that of the EPA ratings. (example, CTS 18/27mpg)

Stupid marketing man, if I were GM I would develop a tamed and smaller version of the LS2 and sell that as the junior Corvette engine keeping up America's best motoring traditions.

Funny you mention that because that is what GM is doing. Its called the LS4, a 5.3-5.4L V8 with DOD. Its going to be in the next impala/monte carlo, rumored Camaro, possibly bonivelle and a few others.

[Slicks]

Originally Posted by Matra et Alpine

2 possible reasons - it's not workign out how GWB thought it would - afer all I didn't hear him ask the American voters to commit to provide larged fighting force STILL engaged in street guerilla warfare for the next 5+ years

Keep thinking that...

They are in cases now that compact 6 and more speed boxes with fsat pre-elector shifts are about.
WHY woudl it make it "less efficient" ? Wider torque does not NEED the designer to change the gears, they can retain the gears and give better drivability. THAT's why wider bands are wanted, to give the driver better options.

Smaller gears = less time your in the powerband. The smaller the gear the faster the engine revs through it. Why do you think that a car like the S2000 gets such shitty gas milage? Its got tiny ass gears to keep up with the high revving engine.

[Matra et Alpine]

Originally Posted by Slicks

Smaller gears = less time your in the powerband. The smaller the gear the faster the engine revs through it. Why do you think that a car like the S2000 gets such shitty gas milage? Its got tiny ass gears to keep up with the high revving engine.

I CLEARLY pointed out numbers of gears.
The old concenr you're citing is from the days of 4-speed manual boxes and then folsk woudl stick on overdrives to try to get fuel consupmtion down for the tests.
AND the comment on smaller gears, time in powerband seems to forget that the DRIVER controls that. IF you accelerate everywhere full-on then your consumption WILL be shitty - regardless of the engine/gears
I don't see the logic you're promoting, can you explain.

PS: Can you cite me the GWB speech where he DID say it woudl be for the long-term when he sought backing to start this war ??

[henk4]

Originally Posted by Slicks

BIGNO! "HEMI" just like "hightech" is a marketing technique.


I use EPA figures because everyone drives differently, there are different elevations, temperatures, traffic etc. Using EPA cancels out most of that, and gives you a good figure. So far, every car Ive kept mpg on match that of the EPA ratings. (example, CTS 18/27mpg)


Funny you mention that because that is what GM is doing. Its called the LS4, a 5.3-5.4L V8 with DOD. Its going to be in the next impala/monte carlo, rumored Camaro, possibly bonivelle and a few others.

But we (or the testers) don't buy the marketing of the Hemi and recognise it for what it is, a good old US gas guzzler. The remarks on its fuel consumption also came from other testers in other countries, but I don't have them at hand here, but if I remember correctly it was very difficult to get a more than 5 km per litre during city driving. We I am back home I'll see if I can find some ECE figures for the 300.
For comparison purpose I prefer test measurements as they also show what you have to pay if you really want to use the full power of the car.

Why can't they make the LS4 about 4 litres or so. What is DOD?

Just remembered that in Europe we also have a small block OHV V8 tradition, with the 2 litre Fiat 8V and more importantly the alloy 2.6/3.2 BMW engine used a.o. in the 507 during and which was considered quite a good engine in its time. When BMW finally started makimg V8 engines for the 7 and the 5 series however they never looked back and went for the conventional DOHC design.

I guess Matra already sufficiently replied to your remark about the efficiency of diesel engines and the gearing of a car. I really don't see what you are aiming at. I have a five speed gearbox and the car has a topspeed of 190 kph, and I absolutely can't complain about its efficiency. Just keep it in the rev band from 1200-3000 and it is doing fine. If you stay below 2000 that's fine too, the power is there. Max torque is at 1750 and max power at 4000 (3000 revs in fifth gives 150 kph)

[Slicks]

Originally Posted by Matra et Alpine

I CLEARLY pointed out numbers of gears.
The old concenr you're citing is from the days of 4-speed manual boxes and then folsk woudl stick on overdrives to try to get fuel consupmtion down for the tests.
AND the comment on smaller gears, time in powerband seems to forget that the DRIVER controls that. IF you accelerate everywhere full-on then your consumption WILL be shitty - regardless of the engine/gears
I don't see the logic you're promoting, can you explain.

No, im definetly thinking about 6 speed boxes, the S2000 has a 6 speed.
Ok think of this. Same engine different gears. The driver has the same amount of throttle input, the one with the smaller gearing is going to be switching more often, and probably revving higher due to the fact that the gears are smaller.

PS: Can you cite me the GWB speech where he DID say it woudl be for the long-term when he sought backing to start this war ??

What?
Im hate politics, so im not going to start to talk about them.

[Slicks]

Originally Posted by henk4

But we (or the testers) don't buy the marketing of the Hemi and recognise it for what it is, a good old US gas guzzler. The remarks on its fuel consumption also came from other testers in other countries, but I don't have them at hand here, but if I remember correctly it was very difficult to get a more than 5 km per litre during city driving. We I am back home I'll see if I can find some ECE figures for the 300.
For comparison purpose I prefer test measurements as they also show what you have to pay if you really want to use the full power of the car.

Like i said, different drivers and different roads. And any car using its "full power" isnt going to be efficient... Like I said its still getting better gas milage than more 6 cylinder and 8 cylinder engines.

Why can't they make the LS4 about 4 litres or so. What is DOD?

What would making it a 4 liter help? To make the same amount of power that would mean it would have to rev higher, which would inturn hurt the torque curve. On top of that a 4L might require a totally new block, which is more $$$ for nothing gained. The 5.3L LS4 is already going to be smaller and lighter than most V6s (just like the LS1) on the market.
DOD is displacement on demand, the same thing Chrylser is using. Solenoids deactivate 4 or 6 cylinders, making the V8 into a V6 or 4 for better gas milage.

Just remembered that in Europe we also have a small block OHV V8 tradition, with the 2 litre Fiat 8V and more importantly the alloy 2.6/3.2 BMW engine used a.o. in the 507 during and which was considered quite a good engine in its time. When BMW finally started makimg V8 engines for the 7 and the 5 series however they never looked back and went for the conventional DOHC design.

Have you ever read anything that BMW owners say??? Ask the enthusisests about OHV, they'll come out whailing "old tech." I see it all the time in C&D letters sent in, people poke fun at engines not making 100hp/l, and not using ohc with VVT.

I guess Matra already sufficiently replied to your remark about the efficiency of diesel engines and the gearing of a car. I really don't see what you are aiming at. I have a five speed gearbox and the car has a topspeed of 190 kph, and I absolutely can't complain about its efficiency. Just keep it in the rev band from 1200-3000 and it is doing fine. If you stay below 2000 that's fine too, the power is there. Max torque is at 1750 and max power at 4000 (3000 revs in fifth gives 150 kph)

Sounds good, but I explained it above.
And thats actually about what I drive at in my petrol engine.

[henk4]

Originally Posted by Slicks

Like i said, different drivers and different roads. And any car using its "full power" isnt going to be efficient... Like I said its still getting better gas milage than more 6 cylinder and 8 cylinder engines.


What would making it a 4 liter help? To make the same amount of power that would mean it would have to rev higher, which would inturn hurt the torque curve. On top of that a 4L might require a totally new block, which is more $$$ for nothing gained. The 5.3L LS4 is already going to be smaller and lighter than most V6s (just like the LS1) on the market.
DOD is displacement on demand, the same thing Chrylser is using. Solenoids deactivate 4 or 6 cylinders, making the V8 into a V6 or 4 for better gas milage.



Have you ever read anything that BMW owners say??? Ask the enthusisests about OHV, they'll come out whailing "old tech." I see it all the time in C&D letters sent in, people poke fun at engines not making 100hp/l, and not using ohc with VVT.

Sounds good, but I explained it above.
And thats actually about what I drive at in my petrol engine.

The figures I ws giving were compiled by the same testers, using the same methods and the same roadsections. Each car has to go through a certain number of test items and at the of the test (usually up to a 1000 miles) they calculate average consumption. This makes the resulting figures quite comparable, but usually the results are a bit on the high side given the fact that the performance of the car has to be fully measured and as they are German topspeed can be legally established . But again, that goes for every car subjected to these tests. (If I remember correctly for my car they arrived using about 1.5 litre per 100 km more than I do on average). The only varying factor can be the climatological circumstances. How are the EPA measurements being established? Do they actually drive the car or is it done under laboratory conditions?

When I read your description of the LS4 I think that the end of the GM V6 is imminent. Just remembered an earlier post wehre the 3.8 litre V6 was claimed to be the most economical V6 produced.

I don't care what owners of modern BMW's say. My favourite BMW's are the 507, the 3200 CS and the 2800CS. (the first two have the OHV V8) What you quote they don't say in Europe though. I was merely referring to the fact that the last european OHV smallblocks (and two litre is small, I even have a picture of the block to prove that, but I cannot upload it right now) were built in the fifties. (I think the Tatra air cooled rear fitted V8 also has an OHV but I am not sure)

You have not explained why the fact that the diesel engine has low end torque and not at the same time high end torque, makes it less efficient.
I am glad you drive in the same rev range as I do, but I doubt very much whether you will also turn out between 40-50mpg.

Another thing is that it just struck me that Ford has replaced almost all its OHV engines now with OHC versions. Are they not trying to sell cars to the same people GM does? Are they not being condemned by roadtesters in the USA that they produce fuel inefficient quasi high tech automobiles? (I don't read american magazines, hence the question)

[Matra et Alpine]

Originally Posted by Slicks

No, im definetly thinking about 6 speed boxes, the S2000 has a 6 speed.
Ok think of this. Same engine different gears. The driver has the same amount of throttle input, the one with the smaller gearing is going to be switching more often, and probably revving higher due to the fact that the gears are smaller.

BUT if he's revving higher THEN he is stayign in each gear LONFER and si NOT switching more often.
That's why I can't grasp the point you're trying to make.
Can you try again ? Trye explaining each situation completely. Ta.

Im hate politics, so im not going to start to talk about them.

Sorry Only asked because you through the Bush comment in first
Ok to drop it.

[Matra et Alpine]

Interesting insight into cam thinking in America.

In amongst all the news on the 2005 Mustang, this little gem surfaced from the words of Ford ....
"The V-6 Mustang customer hasn’t been forgotten either. The new 90-degree, single-overhead-cam 4.0-liter engine produces 202 horsepower standard – up from the prior pushrod engine’s 193 hp – for a new level of performance. Peak torque is 235 foot-pounds, 10 more than the prior model’s 225.
So FORD, went OHC to get 10 more horses and 10 more lbft

"The three-valve heads are smaller than the previous two-valve heads, reducing weight. They also offer a more direct, "ported" style path to the valves for better air flow at peak engine speeds. Magnesium cam covers suppress valve train noise and reduce weight. Taking weight out at the top of the engine helps lower the car’s center of gravity and its roll-center axis, improving handling."
So they clearly didn't go the route of adding OHCs to INCREASE the weight up to

19/28 for the V6 and 17/25 for the V8, which against the Corvette's 18/28 seems comparably good ( for American cars ) ESPECIALLY given the 'stang weighs 3300-3500 lbs and the 'Vette only 3200lbs.

*figures from stangnet.com - where there are some SUPERB pics of 05 Mustang

[Slicks]

Originally Posted by henk4

The figures I ws giving were compiled by the same testers, using the same methods and the same roadsections. Each car has to go through a certain number of test items and at the of the test (usually up to a 1000 miles) they calculate average consumption. This makes the resulting figures quite comparable, but usually the results are a bit on the high side given the fact that the performance of the car has to be fully measured and as they are German topspeed can be legally established . But again, that goes for every car subjected to these tests. (If I remember correctly for my car they arrived using about 1.5 litre per 100 km more than I do on average). The only varying factor can be the climatological circumstances. How are the EPA measurements being established? Do they actually drive the car or is it done under laboratory conditions?

Supposedly this is how its done:
"The city test is 11 miles and consists of 23 stops, with an average speed of 20 mph and about five minutes of idling. The 10-mile highway test includes no intermediate stops, minimal idling, and an average speed of 48 mph."
That is really all I could find, even EPAs own site doesnt have how its done (or I couldnt find it atleast). I found that info on a hybrid car website.

Now if you think about it, testing in a laboratory wouldnt be that bad. As long as all tests were done the same. Because that cancels out all the various things that could hurt/help gas milage in real world driving. So when real world driving, all cars are hurt when its cold, or all cars are hurt when its hot etc. And all hills are at a different incline, and cars on the same hill will be hurt differently anyway because of gearing and the powerband. So laboratory testing can give you a figure of "normal" driving on a "normal" day.

When I read your description of the LS4 I think that the end of the GM V6 is imminent. Just remembered an earlier post wehre the 3.8 litre V6 was claimed to be the most economical V6 produced.

Why is that? The GM V6 is still cheaper, and V6s still have that marketing influence of sucking up less gas than V8s. On top of that insurance would surley be cheaper on a weaker V6 car, than a more powerful V8 car. And then think about smaller cars and trucks that wont offer the V8, but still some power : a V6 (like my Blazer).
Also the LS4 is supposed to be in the "SS" kind of models. Like the Impala is a V6, then the Impala SS is the LS4. These LS4s are going to be optional engines for most of the cars.

I don't care what owners of modern BMW's say. My favourite BMW's are the 507, the 3200 CS and the 2800CS. (the first two have the OHV V8) What you quote they don't say in Europe though. I was merely referring to the fact that the last european OHV smallblocks (and two litre is small, I even have a picture of the block to prove that, but I cannot upload it right now) were built in the fifties. (I think the Tatra air cooled rear fitted V8 also has an OHV but I am not sure)

Heres a letter from an earlier C&D that I was skimming through:
"Let's see if ive got this right regaurding the Cadillac CTS-V test (March). Cadillac wants to compete, head on, with BMW, MB, and Audi in the performace luxury sports-sedan category. So it develops a car based on a 1950s engine design and sends it for a test with a leaky front tire, and faulty oil temperature sensor. Then during the test it turns out this wannabe Bimmer beater exhibits a 1960s wheel hop problem and a 1970s mpg figure (16mpg). Am I the only one that thinks the Germans arent worried?"
Well best thing is in a later article (cant remember if its C&D or MT) the CTS-V stomps a Audi and MB on the track. The BMW M3's city milage is 16mpg, and is a lighter, smaller car too. This is the kind of crap im talking about.

You have not explained why the fact that the diesel engine has low end torque and not at the same time high end torque, makes it less efficient.
I am glad you drive in the same rev range as I do, but I doubt very much whether you will also turn out between 40-50mpg.

No, its fine for daily driving and "normal" cars. But I said for performance cars it would be very benificial to have high end power with that low end power. And, yea, I cant get 40-50 mpg in a 4 speed geared for towing, 4000lbs truck based SUV, not a big surprise.

Another thing is that it just struck me that Ford has replaced almost all its OHV engines now with OHC versions. Are they not trying to sell cars to the same people GM does? Are they not being condemned by roadtesters in the USA that they produce fuel inefficient quasi high tech automobiles? (I don't read american magazines, hence the question)

Yea, they did that in the early to mid 90s mainly, same time it was hard to make power thanks to the EPA. Same time that GM went to Lotus to make them a 500lbs DOHC LT5. They are selling to the same people GM is, but they can say they have a "high tech" engine now. And no, roadtesters dont care, because like everyone else they cant tell the difference. And for the fuel inefficent cars, like the Mustang, people dont care because its a performance car.

[Slicks]

Originally Posted by Matra et Alpine

BUT if he's revving higher THEN he is stayign in each gear LONFER and si NOT switching more often.
That's why I can't grasp the point you're trying to make.
Can you try again ? Trye explaining each situation completely. Ta.

No, because he is revving higher and not getting to the speed of the bigger geared car. Lets say hes trying to get to 50mph, the high geared car revs to 2000rpms and switchs (30mph) and gets to 50 at 3000PRMs in 2nd. The smaller geared car revs to 4000RPMs (30mph) and switches, and gets to 50 in 2nd at 5000RPMs.

Sorry Only asked because you through the Bush comment in first
Ok to drop it.

I dont understand what you were even getting at.

[Slicks]

Originally Posted by Matra et Alpine

Interesting insight into cam thinking in America.

In amongst all the news on the 2005 Mustang, this little gem surfaced from the words of Ford ....
"The V-6 Mustang customer hasn’t been forgotten either. The new 90-degree, single-overhead-cam 4.0-liter engine produces 202 horsepower standard – up from the prior pushrod engine’s 193 hp – for a new level of performance. Peak torque is 235 foot-pounds, 10 more than the prior model’s 225.
So FORD, went OHC to get 10 more horses and 10 more lbft

Hardly, if you look at the facts youll see.
The OHC V6 engine in the 05 Mustang has a higher compression, and larger displacement then the OHV V6 in the 04 mustang.
Oh and look at this, the 04 mustang V6 still gets better gas milage...

"The three-valve heads are smaller than the previous two-valve heads, reducing weight. They also offer a more direct, "ported" style path to the valves for better air flow at peak engine speeds. Magnesium cam covers suppress valve train noise and reduce weight. Taking weight out at the top of the engine helps lower the car’s center of gravity and its roll-center axis, improving handling."
So they clearly didn't go the route of adding OHCs to INCREASE the weight up to

True, so they use light weight material to help out the top heavyness. BTW that 2 valve per cylinder design they're talking about is their previous SOHC, not an OHV if you didnt know that.

19/28 for the V6 and 17/25 for the V8, which against the Corvette's 18/28 seems comparably good ( for American cars ) ESPECIALLY given the 'stang weighs 3300-3500 lbs and the 'Vette only 3200lbs.

Yes it does, "for american cars" , but can you name a similar powered car (using petrol) from some where else that gets close to the gas milage of these? All the european cars with similar power and weight are getting around 16/24mpg at best, same goes for japanese cars.

[Matra et Alpine]

Originally Posted by Slicks

No, because he is revving higher and not getting to the speed of the bigger geared car.

THIS is where I think you're missing the key fact.

WHY are they not reaching the speed ? Smaller gear + higher revs = laonger gear and lower revs.
I tihnk this is where you're getting it twisted and making the wrong conclusion.

Lets say hes trying to get to 50mph, the high geared car revs to 2000rpms and switchs (30mph) and gets to 50 at 3000PRMs in 2nd. The smaller geared car revs to 4000RPMs (30mph) and switches, and gets to 50 in 2nd at 5000RPMs.

So they've actually switched the same numebr of times
You're position had been that they needed to change gearrs more often, I dont' see how you have described that at all
You want to try again or just drop it ?

[Matra et Alpine]

Originally Posted by Slicks

Hardly, if you look at the facts youll see.
The OHC V6 engine in the 05 Mustang has a higher compression, and larger displacement then the OHV V6 in the 04 mustang.

And guess what desingers do to increase compression ?
THEY increase valve size and gas flow !
To do that you have to go multi-valve and/or larger openings to do THAT you go OHC.
QED.

Oh and look at this, the 04 mustang V6 still gets better gas milage...

Where did you come up with that ?
According to Ford, the 04 was 20/29 or 17/25 and the 05 is 19/28 17/25
BUT look closer and you see the 05 model is running on 62 versus the 04 59 tred wheels. SO the extra rolling resistance will soak up an easy couple of mpg THAT was a marketing choice by Ford on what to use the oomph of the engine for
http://www.fordvehicles.com/cars/200...eatures/specs/
http://www.fordvehicles.com/cars/200...eatures/specs/
So it doesn't REALLY get better mileage under the same setups
AND it's 1mpg different on ONE test of ONE engine. Wow you can be pedantic can't you
BTW, the 04 Mach 1 used DOHC and returned the same 19/28 consupmtion

True, so they use light weight material to help out the top heavyness. BTW that 2 valve per cylinder design they're talking about is their previous SOHC, not an OHV if you didnt know that.

Hadn't I thought only the Mach 1 was OHC, Checkign up for the above I see it was originally SOHC on the rest of the range of the V8s.

Yes it does, "for american cars" , but can you name a similar powered car (using petrol) from some where else that gets close to the gas milage of these? All the european cars with similar power and weight are getting around 16/24mpg at best, same goes for japanese cars.

We've gone through this before and you cite US examples with worse consumption and I cite Eureopan examples with better consumption and you dont' care
HOWEVER, I DID notice a VERY important point on consupmtion especially motorway. You listed earlier that it's 48mph over in the US. In Europe its 55mph. So 2 things. First, reading Eureopan consumption figures for motorway and mixed will make Eureopan figures read worse as they are at a higher speed. SECONDLY designers DO try to make their cars look better consumption-wise and European setups will be better at 55 than at 48. So unless they are willing to do a complete gear setting and engine remapping they WILL return worse figures underthe TESTS but no difference in the real world.
Worth remembering when "slagging" Eureopan cars as a test is NOT the real world. Equally too for US cars over here.