why do people who dont like vtec ... dont like vtec?

[hightower99]

Originally Posted by fpv_gtho

How else do you expect to compare 2 systems and their effectiveness? You want to go to a % gain on the same engine with and without the systems?

There are many things to compare...

milage, torque curve, redline, peak HP, thermal efficeincy (rated in lbs/hp/hr or kg/kWh)

Also a neat fact the S2000 engine actually makes more power when you kill the VTEC system... loses low rpm hp and gets even peakier but has a higher peak hp.

[2ndclasscitizen]

Originally Posted by hightower99

Also just because an engine is small and has a high HP/L rating does not mean it is not driveable, you just have to drive it differently then you would if it was a large V8...

A car with 657nm is gonna be easier to drive around town than one with 220nm

[hightower99]

Originally Posted by 2ndclasscitizen

A car with 657nm is gonna be easier to drive around town than one with 220nm

Actually you wouldn't know anything about how well they drive around town until you know the weight of the car the gearing and the shape of the torque curves and the peak hp...

[2ndclasscitizen]

Let's see, Wouter said he'd prefer an LS7-powered car (where I got 657nm from), so that's only a Z06 at the moment. Check out the Top Gear ep where Clarkson drives that. He moves off in 5th no problems at all with very little revs. That basically means around town you could chuck it in say 3rd and just leave it there. No shifting up and down all the time as you'd need to in an S2000, (220nm) which every review I've read says you need to.

[KnifeEdge_2K1]

Originally Posted by hightower99

HP/L is totally irrelevant what is relevant is that BMW's M5 is powered by a 5L V10 that redlines at 8250rpm and produces 500hp (and it has won 4 international engine of the year awards). Also the best engine BMW has is the new N52 series Inline 6 engines that have Valvetronic and Double VANOS. This engine series is very young and as it progresses it will prove to be BMW's most powerfull I6.


I doubt you knowledge on the subject for a few reasons but one of them is you referring to the valvetronic system as having "a complicated gearing system" because it only has 2 gears and they are not complex at all. Double VANOS happens to have the widest range of adjustment (60deg) and the fastest reaction time (roughly a 1/4 of VTEC's cam phasing part) and the most points making it the most smooth (roughly 50 times more points than VTEC's cam phasing part) cam phasing system to date. Next Valvetronic is the only system in production that allows a gas fuelled engine to run without throttle valves. The response is faster and smoother than ITB systems. It constantly and smoothly variates valve lift optimising it for any rpm and pedal position. Now it is a very young system and when it first came out it struggled to hold on at 6000rpm. Now only a few years after it's release it is totally reliable up to 7200rpm and a test engine can hit 8000rpm without breaking. In a few years you will see valvetronic systems capable of sustained 9000rpm operation. I have looked at most of the systems available on cars today and BMW's comes out on top as the best.

To stress the point of BMW's sytem being the best ask yourself this question...

Which company has won the most "International engine of the year" awards

Answer: BMW...

60 degrees ... tell me when the hell do you ever need to phase the camshaft 60 degrees

as for valvetronic, you forgot to mention that its only acting on the intake vales, as it's primary purpose is to control the amount of air being let into the engine and gives no benefit to the exhaust side which on a vtec engine does change the cam profile to allow quicker evacuation of exhaust gasses.

taken from the autozine technical school website
"Now you might think about Honda's VTEC. Can Valvetronic use its variable lift to increase power like VTEC ? Sadly, Valvetronic is actually less efficient at high rev than conventional engines, let alone VTEC. As you can see, the camshaft drives the long intermediate rocker arms, in turn drive finger followers, this generates quite a lot of friction. Therefore the efficiency and refinement of Valvetronic engines drop rapidly at over 6,000 rpm. No wonder in the foreseeing future BMW will not equip its M-power engines with Valvetronic."

and i trust this dude alot more then i trust you, n believe me, 99% of this forum feels the same way as me

[KnifeEdge_2K1]

friction losses when as rpm goes up, alot more then conventional systems, you can use low friction linings and what not but that doesnt change the fact it has an inherent flaw in the system

[hightower99]

Originally Posted by 2ndclasscitizen

Let's see, Wouter said he'd prefer an LS7-powered car (where I got 657nm from), so that's only a Z06 at the moment. Check out the Top Gear ep where Clarkson drives that. He moves off in 5th no problems at all with very little revs. That basically means around town you could chuck it in say 3rd and just leave it there. No shifting up and down all the time as you'd need to in an S2000, (220nm) which every review I've read says you need to.

Does the S2000 have a super heavy clutch? No... Is it prone to stalling? No... When cruising at 60mph in 5th will you be topping 5-6000rpm.. Yes.

[hightower99]

Originally Posted by KnifeEdge_2K1

60 degrees ... tell me when the hell do you ever need to phase the camshaft 60 degrees

60 degrees total (so +/- 30) and that is pretty much as far as you want to go.

Originally Posted by KnifeEdge_2K1

as for valvetronic, you forgot to mention that its only acting on the intake vales, as it's primary purpose is to control the amount of air being let into the engine and gives no benefit to the exhaust side which on a vtec engine does change the cam profile to allow quicker evacuation of exhaust gasses.

That is because the valvetronic system is still very young and because the standard lift is good on it's own and only needs the timing change of the VANOS system to be effective.

Originally Posted by KnifeEdge_2K1

taken from the autozine technical school website
"Now you might think about Honda's VTEC. Can Valvetronic use its variable lift to increase power like VTEC ? Sadly, Valvetronic is actually less efficient at high rev than conventional engines, let alone VTEC. As you can see, the camshaft drives the long intermediate rocker arms, in turn drive finger followers, this generates quite a lot of friction. Therefore the efficiency and refinement of Valvetronic engines drop rapidly at over 6,000 rpm. No wonder in the foreseeing future BMW will not equip its M-power engines with Valvetronic."

Yeah I read that too and I can tell you two things 1: that is old info Valvetronic can already run at a sustained 7200rpm in cars that BMW makes now and 2: whoever wrote that article missed something because the whole point of valvetronic is to increase milage AND power. Also he doesn't give any sort of data at all to show the increased "friction" and that it is worse than a normal static lift system. It looks like he heard that valvetronic doesn't work over 6000rpm and guessed that it was mostly because of friction from the pictures. In reality it has to do with many things like the added inertia of the (as of yet) large parts, the fact that the original leverage arms and force angles were not optimum (most of the 1200rpm increase came from changing these) and also the fact that higher rpms require stronger valve springs which put too much stress on the system. Friction is actually quite low in the Valvetronic system (everything is on ballbearings and rollers). Now as I said before this system is still young and as it changes will soon be able to sustain 9000rpm operation and it will be used on both intake and exhaust sides.

Originally Posted by KnifeEdge_2K1

and i trust this dude alot more then i trust you, n believe me, 99% of this forum feels the same way as me

I don't want you to just trust me I want you to read what I write and make your own descision. If you think there is a hole in my explanations then discuss it. You have shown in other threads that you are capable of maintaining a good discussion even with me.

[Slicks]

Originally Posted by KnifeEdge_2K1

but there's a limit to how far you can bore it out, and boring (ok i cant spell it) makes the side walls thinner, and hence takes it closer to the limit at which it's still safe, and hurts reliability, a stock engine is designed with all these parameters in to account

if you were to design an engine from scratch, a 2L engine is going to be smaller then a 3L one given similar constraints on materials, costs, bla bla bla
that's my point, you cant compare engines from different manufacturers which were intended for hugely different purposes and were made with vastly different budgets

given no other information would you say a 3L engine is smaller/lighter then a 2L one ?? ofcourse not

it isnt the end of the story just because you say it is
you're right in that a 200 hp is 200hp regardless of whether it came from a 2L or 4L, or petrol or diesal, but the point is a 200hp 2L will be compared to cars in the 2L class, a 200hp 4L will be compared to cars in the 4L class
if you compare the 200hp 4L to the 200hp 2L which would you say is better? the 4L cuz it has more displacement and thus more potential ?? i sure as hell wouldnt, it'd be a piece of shit compared to other 4 litre engines available, and the 200hp 2L is already so refined i wouldnt have to do much to it

if ultimate power was all that mattered, you'd see the v10 from the viper in every car in dodges line, and all manufacturers would fit the biggest engine possible into every car's engine bay, what you're proposing is retarded

so you would rather pay the same amount of money for a piece of shit engine that you have to work on for it to be good ... as opposed to a small engine which costs just a bit more and has had hundreds of engineers work on it, making it better then you could ever possibly do on your own ... youve got issues mate ...

MY post went completely over your head... (and btw I would like to know what 4 cylinders you were talking about)
IF and only IF the 3L block MUST have the exact ratio of displacement to siez as the 2L, then it would be bigger.

Im talking about STREET CARS, there is no displacement classes on the street. And your looking at just small numbers again, chances are the 4L engine is going to have a much better powerband(and probably better acceleratoin because of it), and be under a lot less strain.
I never said ultimate power is the only thing that matters, obveously thats wrong. For starters were talking about performance cars, so drop the whole "dodge lineup" argument, most of those are are family commuter cars and arnt after power. Manufacturers use whats available and cost efficient for the car.

I rather pay LESS money for a MORE powerful V8 (compared to the puny 240hp F20C) thats hardly larger or heavier(and has much more potential). hp/l is not "technology", hp/WEIGHT and SIZE are, because that actually matters in the REAL WORLD.
I cant even imagine what you were thinking when you wrote:
"as opposed to a small engine which costs just a bit more and has had hundreds of engineers work on it"
You are implying that the V8 in this matter hasnt had hundreds of engineers working on it, which is a (bad) assumption. Its not always about extracting the most amount of power from the engine at hand, but the right amount of power for that car.

[Slicks]

Originally Posted by hightower99

You mean low rpm HP not torque...

HP is one of the only relevant statistics to compare engines with.

Also just because an engine is small and has a high HP/L rating does not mean it is not driveable, you just have to drive it differently then you would if it was a large V8...

No, what he said was correct, it was a quote from Carroll Shelby. Your car accelerates on your torque curve exactly, if your making 300ft.lbs at 2000RPMs and 300ft.lbs at 4000RPMs you will be making double the hp, but wont be pulling any harder in the same gear.
Peak hp is irrelivent in many cases, lets take the infamous "dyno queen" Supras for example. They are known as dyno queens because they make OMG 1000hp!$!@@#$@#, but end up only being able to run 11s or so in the 1/4 mile. Why? Because they are only making that 1000hp for like 200RPMs, the torque curve looks like: ______^

[2ndclasscitizen]

Originally Posted by hightower99

Does the S2000 have a super heavy clutch? No...

Does a heavy clutch worry me? No, I drive a truck at work. I like a heavy clutch, it's easier to modulate. And if you don't have to change gear all the time because it's got lots of torque, it's not going to matter that much

Originally Posted by hightower99

Is it prone to stalling? No...

Stalling is not the cars fault, it's your fault for not knowing how to drive the car properly and stalling.

Originally Posted by hightower99

When cruising at 60mph in 5th will you be topping 5-6000rpm.. Yes.

And that's a good thing? You could stick a Z06 in 6th at 100kmh and be only turning over at ~1500rpm, and have adeqaute grunt to move off.

[KnifeEdge_2K1]

Originally Posted by hightower99

Does the S2000 have a super heavy clutch? No... Is it prone to stalling? No... When cruising at 60mph in 5th will you be topping 5-6000rpm.. Yes.

it does have 6 gears ...

[KnifeEdge_2K1]

Originally Posted by hightower99

60 degrees total (so +/- 30) and that is pretty much as far as you want to go.

That is because the valvetronic system is still very young and because the standard lift is good on it's own and only needs the timing change of the VANOS system to be effective.


Yeah I read that too and I can tell you two things 1: that is old info Valvetronic can already run at a sustained 7200rpm in cars that BMW makes now and 2: whoever wrote that article missed something because the whole point of valvetronic is to increase milage AND power. Also he doesn't give any sort of data at all to show the increased "friction" and that it is worse than a normal static lift system. It looks like he heard that valvetronic doesn't work over 6000rpm and guessed that it was mostly because of friction from the pictures. In reality it has to do with many things like the added inertia of the (as of yet) large parts, the fact that the original leverage arms and force angles were not optimum (most of the 1200rpm increase came from changing these) and also the fact that higher rpms require stronger valve springs which put too much stress on the system. Friction is actually quite low in the Valvetronic system (everything is on ballbearings and rollers). Now as I said before this system is still young and as it changes will soon be able to sustain 9000rpm operation and it will be used on both intake and exhaust sides.


I don't want you to just trust me I want you to read what I write and make your own descision. If you think there is a hole in my explanations then discuss it. You have shown in other threads that you are capable of maintaining a good discussion even with me.

the vanos might have the highest range at 60 degrees but since the gains from merely phasing the camshaft are so small, that those extra 10 or so degrees (i have no clue what other systems are capable of but i assume it's in the 40-50 degree range) wont make much of a difference

as for the valvetronic, that is pretty much the only info ive had other then bmw press shit but claims from manufacturers are often heavily inflated.

if the system hasnt changed it still seems like the valvetronic system is less "direct then that used in regular heads, tho it is a clever system i admit, there are to me better ones out there, like ferrari's 3d profile camshafts. the valvetronic however can benefit from nearly infinite cam lift profiles as it's controlled by an electric motor which is probably controlled by the ECU where as the ferrari's is still dictated by the camshaft itself

if they have been able to refine the system to the specs you provided then yes i would have to admit that you're right bout this one, and bmw's would be better, maybe my innate hatred of bmws that has taken over me or something

tho there are systems out there which are better then vtec, vtec was still the first (or one of the first w/e) to be put in mass production cars and started the whole trend, and has remained one of the best and most affordable systems out there till even now, which is why i think it deserves some respect and less knocking, even with the insane fanboys with their lil civics who's vtecs are geared for economy and not performance ..

[KnifeEdge_2K1]

Originally Posted by Slicks

No, what he said was correct, it was a quote from Carroll Shelby. Your car accelerates on your torque curve exactly, if your making 300ft.lbs at 2000RPMs and 300ft.lbs at 4000RPMs you will be making double the hp, but wont be pulling any harder in the same gear.
Peak hp is irrelivent in many cases, lets take the infamous "dyno queen" Supras for example. They are known as dyno queens because they make OMG 1000hp!$!@@#$@#, but end up only being able to run 11s or so in the 1/4 mile. Why? Because they are only making that 1000hp for like 200RPMs, the torque curve looks like: ______^

you forget that torque is changed by gear ratios, just because a car has 500ft-lbs of torque doesnt neccesarily mean it will accelerate faster, gear ratios can easily mask the peakyness of an engine, and ultimately power is what matters at the top end, there are hundreds of variables to take into account, but you're right a fatter torque curve IS better then a tiny one, but also take this into consideration

let's say we have an engine which has a rather fat torque curve and let's arbitrarly set the redline rpm to 7000, if you shorten the stroke and widen the bore, the engine will make less low rpm torque but alot more high rpm power, now you can use the gear ratios to make up for the lower torque at the low end, but extra power you get at the top end will more then make up for that

this isnt going to be true in all cases and ultimately you will run into a barrier you just cant pass

you're also right about the fact that cars arnt ranked on a displacement scale in real life, but most cars in the same class do have similarly sized engines, you're not going to find an 8L engined car in a class of economobiles for example

ive completely lost track of what i wanted to say so i'm jsut gonna stop now and make another post later that's more on topic

[KnifeEdge_2K1]

one last thing, a really fat torque curve isnt always a good thing, say ur torque curve is really fat and lasts 6000rpm, you only stay in each gear for 2 or 3000 rpm so in essence you're wasting another 3-4 thousand rpm, but say you destroked the engine and bored it out, your torque curve is smaller but your gear ratios match it alot better, you'd also have more power and be able to go just as fast so long as you remain in the right gear

i'm not saying this is the best thing to do, since you dont always wanna shift when in everyday traffic, but when you're buying a $30,000+ sports car ... is performance in traffic the most important quality to u ??