Lt5

why did chevy only make the DOHC LT5 for a few years?
it seems that these engines have the potential for huge power and tunability.
were they just too expensive to produce?
not enough demand?
whats up?

Americans don't understand things like Over Head Cams, and 4 Valves Per Cylinder.
They also seem to be confused by Independant Rear Suspension, and Disc Brakes.

Quite simply why make a complex expensive car when you can make a simple cheap one because the vast majority of your market are too niave to know the difference, largely because you have keep the market very tightly regulated and controlled, and kept technological advanced made over seas, that makes cars better to drive, out of your own home market.
The really scary thing is your so stupid, that while you try and rip of your market, you are so bad at it, you also loose money and post record losses.

Add to that the fact that the LT5 was made from unobtanium :) It was a joint venture between GM, Mercury Marine, and Lotus. Expensive, not too well engineered, and it didn't make much power.

And a friendly amendment, moppie... we understand that stuff and gladly purchase foreign vehicles with that technology, but unlike other countries we have not developed in that direction as fast. I like to rather think of it that Americans fear change on such a great level that we must take our change slowly. VERY slowly.

hmm. Is the LT5 related to the LQ1 at all? THAT thing is a monstrosity, a old block with upped bores and DOHC 24 valve head that uses a timing chain to run a dead block cam which then runs a timing BELT to the working cams shoehorned into an engine bay much too small for it, and to top it off, mated to a transmission made out of plastic. And FWD. Bah.

I wish i could have a lumina Z34 body and cushy interior but have a better motor, 5 speed, RWD and a better suspension. That would be cool. I think those luminas are so cool lookin.

but the LT5 just looks so SEXY.
damn american market.
they are dumbing down all automotive technology to the lowest common denominator. automatic transmissions are 'standard'. OHV engines are the norm, and DOHC, even SOHC is shunned in favor of 100 year old technology.

but the LT5 just looks so SEXY.
damn american market.
they are dumbing down all automotive technology to the lowest common denominator. automatic transmissions are 'standard'. OHV engines are the norm, and DOHC, even SOHC is shunned in favor of 100 year old technology.

hmm. Is the LT5 related to the LQ1 at all? THAT thing is a monstrosity, a old block with upped bores and DOHC 24 valve head that uses a timing chain to run a dead block cam which then runs a timing BELT to the working cams shoehorned into an engine bay much too small for it, and to top it off, mated to a transmission made out of plastic. And FWD. Bah.

Tell us what you really think.:grinyes:

Tell us what you really think.:grinyes:
Its a great motor :D right up until the point you have to fix something on it. As per american design - royal PITA. Alternator = drop engine. Coilpacks = under front exhaust manifold. Rear spark plugs = a. cut buts of body or or 2. remove front motor mount and force engine forward. So on and so forth.

Its not related to the LQ1 :) Totally clean slate design never used before or since. No parts interchange with any other engine as far as I know.

And on an LT5, changing an alternator was a very simple three-bolt operation taking 5 minutes tops. Same as most V8 RWD vehicles :)

well then i want the LT5.
or really, just any DOHC 5.0 - 5.7 L V-8
i'd be REALLY happy with a DOHC EFI 383 V-8

think about the possibilities.
F1 ran DOHC V-10 engines up until this year with enormous success.
this year they switched to a... DOHC V-8.

wonder why they aren't still using pushrods tho?
american car companies have proved over and over that they (pushrods) are the most superior form of engine design. what else can compare to the 100 year old OHV configuration...

is moving foreward really that hard?

well then i want the LT5.
or really, just any DOHC 5.0 - 5.7 L V-8
i'd be REALLY happy with a DOHC EFI 383 V-8

Do you guys get the Lexus alloy V8 over there?

Very cheap engine here (used japanese import) which gets shoehorned into everything from toyota hilux to jetboats.

Do you guys get the Lexus alloy V8 over there?



They get them, check out an American Hot Rod magazine, I know 4-5 years ago it was a VERY common swap into a lot of really custom rods.

Its a fantastic motor, really does show how old and out dated the pushrod chevy blocks are.

Yeah, the 1,2, and 3UZ-FE engines are superior in pretty much any way to american pushrod V8's.

I'm sure the new 4.6 liter V8 that toyota is using in the NEW LS is even superiorier. (4UZ-FE maybe?).

american car companies have proved over and over that they (pushrods) are the most superior form of engine design.

and that's why the more technically advanced european and japanesem cars don't use them, right?

Hey guys we're all pretty, so let's not argue :)

They both serve a purpose. Pushrods are perfectly fine reliable technology. They reduce the need for a big long chain or belt (or three on some vee engines) like the OHCs have. Americans often times choose cost over long term reliability. Otherwise we'd all drive Toyotas and BMWs. Europeans generally choose quality over cost. The other thing in the mix is that most other countries don't get American cars as part of their choice. If you go to Germany, you don't have the option of buying an F350 dually pickup so its a moot point.

I like the fact that we have more choices here, but there's a reason why we aren't moving away from pushrods.. its because they're fine and they're cheap. If it aint broke don't fix it.

The other thing is... since when did Americans know what they want? They don't care if their corvette comes with pushrods or muffler bearings. All they know is, push pedal = go faster. If they can get their fix from pushrods they don't know any different.

I like the fact that we have more choices here, but there's a reason why we aren't moving away from pushrods.. its because they're fine and they're cheap. If it aint broke don't fix it.


I think its been pointed out before, but when it comes to choices, Americas automotive market has a lack of choice somewhere behind China and North Korea. I believe its fighting for 3rd place with India, although they did just take large steps to open thie market up, after the Morris Oxfords they've been building under lisence were shown to be a little out dated (although they are still more sophisticated than a Ford F150).



The other thing is... since when did Americans know what they want? They don't care if their corvette comes with pushrods or muffler bearings. All they know is, push pedal = go faster. If they can get their fix from pushrods they don't know any different.

I believe that was the gist of my first post ;)

The American car buying public have become victims of thier own ignorance, and the manufactors are milking it for all its worth.

and that's why the more technically advanced european and japanesem cars don't use them, right?
uhhh, sarcasm. :disappoin

thats the second time this has happened.
i guess this means that i need to take a closer look at what i think is funny...
:screwy: :uhoh: :screwy: :uhoh:

Hey guys we're all pretty, so let's not argue :)

They both serve a purpose. Pushrods are perfectly fine reliable technology. They reduce the need for a big long chain or belt (or three on some vee engines) like the OHCs have. Americans often times choose cost over long term reliability. Otherwise we'd all drive Toyotas and BMWs. Europeans generally choose quality over cost. The other thing in the mix is that most other countries don't get American cars as part of their choice. If you go to Germany, you don't have the option of buying an F350 dually pickup so its a moot point.

I like the fact that we have more choices here, but there's a reason why we aren't moving away from pushrods.. its because they're fine and they're cheap. If it aint broke don't fix it.

The other thing is... since when did Americans know what they want? They don't care if their corvette comes with pushrods or muffler bearings. All they know is, push pedal = go faster. If they can get their fix from pushrods they don't know any different.

Isn't the biggest advantage of pushrods having a really compact engine?

For those familiar with toyota engine codes. the FE suffix denotes the "fuel efficient" version. Imagine if toyota produced a GE version.:smokin:

I would have to politely disagree with some if you in that Americans are not that far behind in technology. I don't think you can buy a car or truck without rear wheel disc brakes any more. Also OHC engines have been around a long time on American made cars. The 2.3L SOHC ford for example. Or the old 2.0L OHC in smaller GM's. Today everyone uses them except for small block chevy's. Ford's V8s are OHC engines, mustangs have had the 4.6 Single or Dual OHC cams since 96. Cadillac Northstar engines are DOHC V8s. Chevy trailblazers have a DOHC inline 6. Chryslers 3.7 and 4.7 engines are also SOHC. If you want to talk about pushrods, why change designs when you can get 500 hp out of a simple pushrod LS7.

I don't think you can buy a car or truck without rear wheel disc brakes any more.
Actually, there are a lot more than you might think. New cobalts and Focuses have rear drums, as well as most new minivans.

If you want to talk about pushrods, why change designs when you can get 500 hp out of a simple pushrod LS7
Because if they made a DOHC LS7 they could very well get more than 500 horsepower out of the engine. Or make a smaller displacement engine that can make 500 HP.

look at it this way.
while american car companies are struggling to make 1 hp/cid,
the mark of a good european car is 100hp/L.

being that there are 62 ci in one L, and 1 hp/cid = 62hp/L
you can see that we are pretty far behind.

which yould you rather have?

i mean really, your average crate 350 V8, the most popular hot rod engine, comes with only 290 hp, and thats out of 5.7 liters.

Yeah, maybe I should have worded that differently. I know there are alot of drum brakes out there still, I work on them all the time. And I like OHC engines as much as the next guy but I guess I am just old school at heart. The gist of my post was that Americans are moving toward those designs but are also slow to give up old technology.

Ok this is great.....Yeah you make 100 hp/1 litre thats great. Torque is what wins races....If that is what you want to talk about if you want good reliability then you get a honda DOHC.

Thing that you guys need to realize that you are comparing apples and oranges.

These are 2 types of different setups! case closed

Ok this is great.....Yeah you make 100 hp/1 litre thats great. Torque is what wins races....If that is what you want to talk about if you want good reliability then you get a honda DOHC.

Thing that you guys need to realize that you are comparing apples and oranges.

These are 2 types of different setups! case closed

No, not neccessairily.

Torque is what wins races....

Wrong, wrong, wrong.

And again i say, WRONG!

I think i'm going to go on a shooting spree if i have to go through this again. :banghead:

oh, but you explain it SOOO well.

Torque is what gives you POTENTIAL to win races.
it is the measure of how much work an engine can do, in absolute terms.
Power is the measure of how QUICKLY an engine can do this work.

an engine from a semi only makes about 3-400 horsepower.
an F1 engine makes nearly double that, but an F1 engine could never pull a semi.
the semi engine makes around 1600 lb/ft of torque, while an F1 engine makes around 300 lb/ft

the torque gives the semi engine the potential to pull the trailer. if a semi engine were to rev to the RPMs that a F1 engine can, it would make astronomical power. fact is, it cant because of the way it is built.

But let's not confuse terminology... Torque is force, not work. Power is potential to do work.

Torque is a static measurement. HP is a function of that force applied over the span of the circle over a period of measured time.

oh, but you explain it SOOO well.


Well its really difficult to explain the differences between torque and horsepower. I was going to bring up the semi and the F1 racer concept, but i didn't have the time.

yeah, but it makes more sense (to me) that way.
oh well.

Well its really difficult to explain the differences between torque and horsepower. I was going to bring up the semi and the F1 racer concept, but i didn't have the time.

Actually if you geared a F1 engine down (and gave it sufficient cooling) then it could pull a truck with no problems.

Of course the large diesel engine is rated for continuous power for thousands of hours, where F1 engines are rated for one race, reaching that power severl times.

Wrong, wrong, wrong.

And again i say, WRONG!

I think i'm going to go on a shooting spree if i have to go through this again. :banghead:

I already got a nice lengthy explanation about that, but since we're talking about performance, let's get realistic, could you build a 7000hp DOHC V8? Talking dragsters here. Why do they use the engines they use?

I already got a nice lengthy explanation about that, but since we're talking about performance, let's get realistic, could you build a 7000hp DOHC V8? Talking dragsters here. Why do they use the engines they use?

It'd depend what fuel you intend to use.
With pump gas you are severely limited and you'd struggle to get much more than the old 100 hp/l unless boosted.
When you start talking alcohol and nitrous the game changes entirely.

let's say top fuel

Americans often times choose cost over long term reliability. Otherwise we'd all drive Toyotas and BMWs. Europeans generally choose quality over cost.

I'd never buy (most) european cars....because I do my own work.

European cars are nice to drive, no argument there. I'd commit suicide if I ever worked at one of their dealerships though. The few I'm forced to work on are enough trama for me. No thank you.

And yes, many american cars are a pain in the butt also, but on average, I still say, no comparison

an engine from a semi only makes about 3-400 horsepower.
an F1 engine makes nearly double that, but an F1 engine could never pull a semi.

the F1 engine installed in a semi, with proper gearing, would make twice the rear wheel torque (power applied to the wheels) than the above mentioned semi truck engine.

To use layman terms....HP is torque adjusted for gearing. If a motor makes twice the HP, it will make twice the wheel torque....with proper gearing.

now would the F1 motor last long in that situation? Definitely not.

the F1 engine installed in a semi, with proper gearing, would make twice the rear wheel torque (power applied to the wheels) than the above mentioned semi truck engine.

To use layman terms....HP is torque adjusted for gearing. If a motor makes twice the HP, it will make twice the wheel torque....with proper gearing.

now would the F1 motor last long in that situation? Definitely not.

It would need an indestructable CVT basically, but yeah it would work. The fact taht it spins at eleventy billion RPM makes up for the fact taht it would need to start at an insanely low gear ratio. But once it got into it's paper thin powerband then it would be faster than the truck.

Then again, Audi has their new diesel Le Mans racer, the R10, and it was kicking ass and taking names from what i remember... all while using less fuel and being much quieter. Lemme look some stuff up on it.

*edit* yar, Audi R10, all aluminum 5.5L V12 twin turbo TDI, >650hp and >810 torques. Pretty crazy.

Isn't the biggest advantage of pushrods having a really compact engine?

The biggest advantage is the low cost, which is why american manufacturers such as GM use push rod designs for their low end engines. High end engines such as Northstar/Aurora, Ecotec and HFV6 uses DOHC and 4 valves per cylinder just as most engines.

Push rod designs aren't really that compact, but this also depends on what you mean with size. A four valve DOCH engine is going to be a bit wider over the heads but that would also be the case with for example push rod hemis. How wide they are is mostly dependant on the valve angle and how the valvetrain is packaged. On the other side, if you use DOHC and 4 valves/cyl the greater flow due to larger port area/bore area and the more aggressive cam profiles which are possible to use with the direct acting cam system it's possible to decrease engine displacement and still get out the same kind of power output.

It would need an indestructable CVT basically, but yeah it would work. The fact taht it spins at eleventy billion RPM makes up for the fact taht it would need to start at an insanely low gear ratio. But once it got into it's paper thin powerband then it would be faster than the truck.

An ordinary gearbox with the proper gearing would work fine for a F1 engine.

The F1 V10 engines used earlier gave well above 200 Nm at low speeds, and since low speeds in a F1 engine is like 5000-6000 rpm that's still 150-200 hp. Remember that those speeds are only slightly above idle speed which is around 4000 rpm. At around 9000 rpm the torque output begins to increase fast, so at about 13000 you have almost the full torque availible, that means well above 600 hp. Then you have more than 900 hp at around 18-19k rpm.

The current F1 engines are a bit weaker but they can still produce about 750 hp with a decent power curve.

It would need an indestructable CVT basically, but yeah it would work. The fact taht it spins at eleventy billion RPM makes up for the fact taht it would need to start at an insanely low gear ratio. But once it got into it's paper thin powerband then it would be faster than the truck..

If you made an intelligently geared 12 speed tranny for the motor, it would work just as well....actually better. The RPM of the power band doesn't matter much when its redlining in first gear at 2 mph. You'd still have double the wheel torque.

and of course its power band is short. Its 1/10th the cc's with twice the power output. That level of performance doesn't come with a free lunch. That shouldn't even need to be reiterated.

Well, but now we're nitpicking reliability. How long would that F1 engine tow 60,000 lbs?

You can use gearing to multiply torque, but HP is already a function of motion. If you take an engine making 1000 lb-ft of torque at 2000 rpms, that means its making 381 hp. If you put it through a 2:1 gearbox, its now putting out 2000 lb-ft at 1000 rpms shaft speed... which is still 381 hp. The problem is the mismatch in gearing for the engine's power band.

You would have to gear an F1 engine down so far that its acceleration would be VERY subpar. You'd go through 50 gears just getting to 30 mph. First gear would literally have to be somewhere around 400:1 final drive to achieve the same speed per range of RPM.

look guys, you are over thinking this.
you COULD pull a semi with a lawn mower engine if you wanted to.
what i was getting at is this...
with identical gearing, an engine with more torque and less power will pull harder than an engine with more horsepower and less torque.

yeah gearing helps, but gearing is only a torque multiplier. Hp is unchanged by gearing. (already mentioned by curtis)

if you have a honda 1.8L high strung engine, you have to rev that thing to the top of its redline before you shift to get the best acceleration. a much torquier engine can be shifted earlier and not lose acceleration.
engines with lots of torque usually come with 5 speed trans.
low torque engines come with 6.
(well not anymore... but thats how it used to be. except 3-4 and 5 respectively)

no, its much simpler than that: maximum acceleration = highest HP.

That simple. The rest of the formula is gearing the motor to best take advantage of the power band. As another has mentioned, even "out of the power band" for an F1 engine, you still "only" produce 600+hp. Which is still way more than the semi engine.

Geared Intelligently, the F1 engine will accelerate that 80K pound mass way faster than a "normal" semi engine, regardless of what torque numbers the semi engine produces. This is a plain simple fact. It should be simple anyway

so, according to this logic, a car will accelerate as quick in fifth as in first???

so, according to this logic, a car will accelerate as quick in fifth as in first???

was that directed to me? And if so, please provide a quote which shows I suggested such

IMO, it's average to the wheels over your gear spread that counts.

If your engine puts out an average 200hp over say 3-5000rpm and you have the gears to keep it in this range. Then you can put down an average of 200hp to the wheels. You'll be faster than an engine which has a higher, but shorter power peak but lower average power over the range the gears are in.

It's a little difficult to explain. But in my definition of average power to the wheels I'm also including gearshifting time. More gearshifts (time putting 0hp to the wheels) is going to lower your average power to the wheels.

To take a 1 ton car to 30m/s in 4 seconds requires an average power to the wheels of:
P=E/t
Ek=1/2m*v^2
P=1/2m*v^2/4
= 500*900/4
=112.5 kW

Approx 150hp.

As we know, a 1 ton car capable of getting to just over 100km/h in four seconds has a peak power way in excess of 150hp. But it needs a peak that high to get an average of 150hp to the wheels during four seconds of acceleration.

The maths in her includes several assumptions (like the car being a solid block, not a collection of rotating shafts). But it illustrates the point well.

no, its much simpler than that: maximum acceleration = highest HP.

That simple. The rest of the formula is gearing the motor to best take advantage of the power band. As another has mentioned, even "out of the power band" for an F1 engine, you still "only" produce 600+hp. Which is still way more than the semi engine.

Geared Intelligently, the F1 engine will accelerate that 80K pound mass way faster than a "normal" semi engine, regardless of what torque numbers the semi engine produces. This is a plain simple fact. It should be simple anyway


I have a feeling that power drops off significantly outside of a few thousand RPM range for an F1 engine like that. The companies don't publish dyno sheets of course, but i'd think that the torque curve would be not very flat and even, and the power curve would be especially peaky.

this is a rather circular argument.

ASSUMING the tranny is set up intelligently (which means, you offer a gear range that allows the motor to stay within the meat of its power curve) ...when you have 12 gears to play with, and the vehicle in question is only geared to 100mph or so, that gives you a lot of flexability.

I have seen one F1 dyno sheet, although I think it was from years ago and is probably not comparable to current engines, but it was surprisingly broad on the power band. The torque was nearly dead flat from 10K RPM's up to 19K RPM's or whatever redline it had. Thats 50% of its RPM range (not accounting for its rather high idle) which btw, is almost exactly the same for a semi engine.

Iv never paid any attention to peak numbers, its always area under the graph that Iv considered far more important, along with how its delivered to the wheels, and how well suited it is to the chassis the engine and drive line are in.

The classic example is the first generation of STi 22B WRX Imprezza's gained lots of attention because they could accelerate from 0-100kph faster than what ever Ferrari was cool at the time. It could even hold off the Ferrari all the way to 160kmph. Sounds impressive until you dig a little deeper and find that all 6 gears in the WRX were so short it hit red line at 180kmph in 6th while the Ferrari was still pulling in 3rd.


Iv worked on a car, that was even de-tuned, to make it faster. Peak power was sacrificed for more power lower down in the power curve, creating a longer flatter curve that made better use of the cars limited (by class rules) gear ratios.

It is quite common for race engines to be detuned to give a more linear, easily controllable power curve. The motoGP bikes, when the 1000cc limit first came out, there were some bikes making over 250hp, but within a year, most of them had detuned them to only about 200-220hp with broader power curves.

I have no doubt the same is for F1 cars and any other serious compitition, you always go for the highest average HP AND smoothest power delivery.

I have a feeling that power drops off significantly outside of a few thousand RPM range for an F1 engine like that. The companies don't publish dyno sheets of course, but i'd think that the torque curve would be not very flat and even, and the power curve would be especially peaky.

I've seen a few power- and torque curves from F1 engines and they aren't that bad. I tried to explain the power curve of a F1 V10 engine in an earlier post.

Even the 1.5 litre turbos from the eighteis aren't that bad. For example Honda's turbo engines gave a high and almost flat torque curve between 7000 and 13000 rpm.

It is quite common for race engines to be detuned to give a more linear, easily controllable power curve. The motoGP bikes, when the 1000cc limit first came out, there were some bikes making over 250hp, but within a year, most of them had detuned them to only about 200-220hp with broader power curves.

I have no doubt the same is for F1 cars and any other serious compitition, you always go for the highest average HP AND smoothest power delivery.

MotoGP has poor grip, so for them driveability is more important than the highest power output availible. A F1 car on the other hand have a good grip, so power is more important than driveability.

These days MotoGP are back around 250 hp due to competition, and more power may very well be on the way, still, this is much less compared to F1, especially since there are much less regulations in MotoGP that limits the power output (except the smaller displacement of course).

In MotoGP throttle modulation is extremly important if you want a fast bike. The engine can almost always produce more power than the bike has grip for, so if the driver should be able to handle the bike throttle modulation is teh key, the engine must respond to every small throttle change just how the driver expect it to respond. Full throttle isn't used that often.

In F1 the driver tend to use two differend throttle positions most of all, no throttle and full throttle (up to 60-70% of a lap can be made at full throttle). No throttle is used during braking and into the turn. Then the driver goes on the throttle softly until full throttle is reached, then the driver keep full throttle until it's time to brake again. So in F1 maximum power is more of an issue, can you increase engine power then you can decrease the lap time. Normally the F1 engine is kept at speeds within a range of 3000 rpm, but speeds down to 4000 rpm can be used in low speed turns so a wide power curve is quite important.