Which engine for the C7 Corvette?

[capriceman]

A 6 liter V12 fits in an Aston Martin Vantage which is smaller than a Corvette. The Vette has had huge, long hood since the 1970s anyway, what is the difference on external engine dimensions. They could probably put any kind of engine they want under there.

Notice too all the arguments for pushrods are cost, less complex, lower exterior dimension, etc. So the goal of the Corvette is to be cheap and not complex, not to be a world class sports car then? Porsche isn't picking the flat 6 in the 911 because it is cheap or easy to make. It isn't easy to make 400-480 hp from a 3.6 liter engine, yet they did it.

The goal of the Corvette is to be an "Affordable" world class sports car. A car that anyone can get if they save up. yet it can compete with the Porsche and Lamborghini for a fraction of the price. It doesn't need a fancy engine to get that horsepower They can use Displacement for raw power and reliability on the cheap so they can spend more on suspension.

[cletus8269]

I think GM needs a DOHC V8, but I don't think GM sees it that way. My guess is the next Corvette will carry on with the 6.2 liter V8, and they will try to get some incremental increases in power, and slight reduction in emissions.

you do realize that the ZR1 is stopped at its HP rating because GM sees the car as barely drivable in anger as it is. hence the driving lessons with purchase... hennessy is tuning the zr1's past GM but that makes GM's liability out of it.

[cletus8269]

The goal of the Corvette is to be an "Affordable" world class sports car. A car that anyone can get if they save up. yet it can compete with the Porsche and Lamborghini for a fraction of the price.

bingo, cause noting is more fun than stealing some rich snot's thunder than outclassing them in a lowly chevrolet thats 1/3 the price. its like showin up at the playground in chuck taylor all-stars and schoolin everyone in their $150jordan's

It doesn't need a fancy engine to get that horsepower They can use Displacement for raw power and reliability on the cheap so they can spend more on suspension.

exactly because in a road race HP sometimes takes a back seat to being able to point it in the right direction.

[cletus8269]

I agree with sports car for the common man so to speak. But the GM always wants to compare the Corvette to Porsche or Ferrarri, etc and the Vette always lags bigtime in interior, etc.

if i can afford a $60K vette... what is $1500 for the full out custom race seat i will put in there to begin with? back on topic

I don't think they should chase the higher end cars, or use a V12, and there should not be a Cadillac version because it will fail.

they usually dont chase em anymore unless they are at risk of going a lap down...

[hyperv6]

They are only smaller when comparing internal displacement, the external dimensions of the DOHC engines are similar sizes to the "larger" OHV V8's.

Many DOHC V8 engines vary in size some larger and some smaller in outside dim. The point is efficent with the smaller displacement makes for a engine that gets better MPG, Emissions and more power. These three things are going to be a must for the future of performance. We need to get more out of less.

Also many of these engines are new clean sheet designs so they are stronger lighter and are not the monsters of the past. Look at the way GM packages the Northstar. For a DOHC engine is is a very tight package. I still would not want to change the starter.

[hyperv6]

cant argue with you much, all are good and valid points. but to me i see it like this

=

the design is time, endurance, and punish tested. just enhance it and go.

You make a good point why change when you can upgrade old proven technology. Note the rack on the back and the liberal use of reflectors.

This one had a real bitchin sub woofer. [i am not kidding some do]. Those Amish kids around here have no time for those stinkin Vettes the English drive.

[smk4565]

The Amish wagon probably has leaf springs as well. I agree, why mess with what works. Clearly keeping status quo is good enough, because the other automakers aren't coming up with new stuff.

[cletus8269]

You make a good point why change when you can upgrade old proven technology. Note the rack on the back and the liberal use of reflectors.

This one had a real bitchin sub woofer. [i am not kidding some do]. Those Amish kids around here have no time for those stinkin Vettes the English drive.

yeah except... my point has been and still is used widely in this century...

besides the fact you find a cam in the block and push rods what of this motor = fail?

now for the 1911... i cant help it that it is widely used by special forces, swat teams, and competition shooters the world over.

Edited August 31, 2009 by cletus8269

[cletus8269]

The Amish wagon probably has leaf springs as well. I agree, why mess with what works. Clearly keeping status quo is good enough, because the other automakers aren't coming up with new stuff.

2009 Z06

The LS7 generates 505 horsepower @ 6,300 rpm, and 470 lb.-ft. of torque @ 4,800 rpm. Those numbers lead to these numbers: 0-60 mph in 3.7 seconds; a quarter mile time of 11.7 seconds @ 125 mph; top speed 198 mph; max lateral grip 1.04 g; 60 mph to zero braking in 111.3 feet.

http://www.automedia.com/2009_Chevrolet_Co...rts20080601cc/2

2009 ZR1

The 60-mph mark arrives in 3.8 seconds (3.5 seconds with 1 foot of rollout like on a drag strip). The quarter-mile disappears in 11.5 seconds at a staggering 128.3 mph.

The Inside Line records continued to fall as we moved on to our handling tests. In direct contrast to the Z06, the ZR1 is stable, communicative and easy to control on its way to a 74.7-mph pass through the slalom. This is the second-fastest slalom speed we've recorded from a production car, behind only the Porsche 911 GT3 RS at 75.3 mph.

a 1.06g average in both directions (our standard) with a peak reading of 1.1g — is second only to the Dodge Viper ACR.

The ZR1 brakes to a halt from 60 mph in 96 feet, which ties this Chevy with the $198,875 Porsche 911 GT2. Chalk this up to Brembo carbon-ceramic brake rotors and massive fixed calipers (six-piston front, four-piston rear).

http://www.edmunds.com/insideline/do/Drive...rticleId=134347

i believe thats aight for a old buckboard horse buggy

[regfootball]

power is power. but the corvette probably needs to add AWD as an option to keep up with the GTR's of the world and so many sports cars are adding AWD as a performance driving thing.

going mid engine would be wrong however, that is like new coke.

they could stand to 'redefine' the v8. at least in an optional motor. i would not be opposed to them staying pushrod, but learning to do more with less. why not a 4 litre, 500hp pushrod motor? that would be real innovation. or push the envelope and try to perfect the camless engine.

of course in that scenario, a camless engine i would prefer to go rwd. keep the car small and light.

it dont matter. computer controlled wheelmotors are the wave of the future someday.

corvette may need an 8 speed auto or dual clutch thing some day too.

Edited August 31, 2009 by regfootball

[capriceman]

SMK Go to this Site Look at where the Corvette ranks and Shut the F*** up for once. Your wrong! The Vette uses leaf springs and push rods yet it still tops the list for fractions of the price. http://www.fastestlaps.com/track2.html

[Chevy Nick]

Many DOHC V8 engines vary in size some larger and some smaller in outside dim. The point is efficent with the smaller displacement makes for a engine that gets better MPG, Emissions and more power. These three things are going to be a must for the future of performance. We need to get more out of less.

Also many of these engines are new clean sheet designs so they are stronger lighter and are not the monsters of the past. Look at the way GM packages the Northstar. For a DOHC engine is is a very tight package. I still would not want to change the starter.

I am disappointed at your remarks, and I'm afraid your understanding of engine design may be incomplete.

When you write

Many DOHC V8 engines vary in size some larger and some smaller in outside dim

, you must be comparing one DOHC engine to another. I can you assure you of a simple fact; a 5.0L OHV engine will always (and I do mean always) be substantially smaller than a 5.0L DOHC engine. It's simple design, the DOHC engine has 3x more camshafts, more timings chains, more sprockets, more lifters, more of everything. This stuff takes up space. Every piston engine requires pistons, rods, a crankshaft, that will be the same either way, but the OHV engine will be more compact on the top end.

As for

better MPG, Emissions and more power

You really don't have to look farther than a comparison of LS1 f-bodies and mod-motor mustangs to realize the fallacy of your remarks. LS1 Camaros can get 30mpg highway when equipped with the T56, and make quite a good deal more power than the DOHC mustang engine. The reason the Camaro has more displacement is because the OHV engine allows for more piston bore and stroke length than the "sophisticated" DOHC design.

I hope that you haven't fallen prey to the import lover argument of "more HP/Liter", which is not taking into account the external dimensions of engines. The Northstar engine is dead, the small-block chevy lives on, that should tell you something. Put direct injection on a LS3 and you've given it another 10-20 years of competitive performance.

[cletus8269]

SMK Go to this Site Look at where the Corvette ranks and Shut the F*** up for once. Your wrong! The Vette uses leaf springs and push rods yet it still tops the list for fractions of the price. http://www.fastestlaps.com/track2.html

i get a smile on my face every time i see that list...

Porsche Carrera GT - slower

Porsche 997 GT2 -slower

Pagani Zonda F - slower

Koenigsegg CCX - slower

Koenigsegg CCR - slower

in fact just over a second ahead of the ZR1 is the Enzo... a car that costs 10x what the ZR1 does...

[hyperv6]

2009 Z06

The LS7 generates 505 horsepower @ 6,300 rpm, and 470 lb.-ft. of torque @ 4,800 rpm. Those numbers lead to these numbers: 0-60 mph in 3.7 seconds; a quarter mile time of 11.7 seconds @ 125 mph; top speed 198 mph; max lateral grip 1.04 g; 60 mph to zero braking in 111.3 feet.

http://www.automedia.com/2009_Chevrolet_Co...rts20080601cc/2

2009 ZR1

The 60-mph mark arrives in 3.8 seconds (3.5 seconds with 1 foot of rollout like on a drag strip). The quarter-mile disappears in 11.5 seconds at a staggering 128.3 mph.

The Inside Line records continued to fall as we moved on to our handling tests. In direct contrast to the Z06, the ZR1 is stable, communicative and easy to control on its way to a 74.7-mph pass through the slalom. This is the second-fastest slalom speed we've recorded from a production car, behind only the Porsche 911 GT3 RS at 75.3 mph.

a 1.06g average in both directions (our standard) with a peak reading of 1.1g — is second only to the Dodge Viper ACR.

The ZR1 brakes to a halt from 60 mph in 96 feet, which ties this Chevy with the $198,875 Porsche 911 GT2. Chalk this up to Brembo carbon-ceramic brake rotors and massive fixed calipers (six-piston front, four-piston rear).

http://www.edmunds.com/insideline/do/Drive...rticleId=134347

i believe thats aight for a old buckboard horse buggy

Imagine if they had a modern engine to work with how much better it would be.

You are missing my point that the present engine is good and I do not disagree but the key to the present engine is large CID. In the future you are going to lose CID and need to do more with less. This are what GM is going to be up against.

Now if all they did is use this engine in a Vette with a limited volume it is not a big deal but if it is to be shared with trucks and Cadillac sedans in the future they are in a volume that they can no longer be as inefficent per liter and with emissions as they are now. They are going to have to fit very tight rules that are coming..

Time to plan for the future as it is at hand.

The only reason we have what we have now is GM could not afford to do the better engine. Today they can and need to. I usd to think this way and was fooled by GM stating we don't need no stinkin OHC and 5 Speed trannys. Now that I have spent a lot of time behind the wheel of modern DOHC and 6 Speeds I found out what we have been missing.

With DI and VVT the new DOHC and Turbo engines come alive in ways we never saw before. GM has the lead with the 4 and V6 and if they don't watch Ford with their Ecoboost marketing will take the lead with an engine not as good yet.

The other factor is many people want the latest and greatest. Technology is king now in many cars. The higher the price the more they expect.

By the way just one county south of me there are still a lot of those buggys still rolling.

[Drew Dowdell]

IF, through some government mandate, there is a shortsighted restriction on engine displacement, then yes, I could see the Corvette being forced to move to a smaller displacement DOHC setup. But until such a restriction exists, there is no reason for the engine to change configuration.

BTW, DOHC has been around in production cars since 1928. The Cam-In-Block pushrod configuration that we know today was released in 1949.

So which car is using the older technology again? Porsche or Corvette?

[hyperv6]

I am disappointed at your remarks, and I'm afraid your understanding of engine design may be incomplete.

When you write

, you must be comparing one DOHC engine to another. I can you assure you of a simple fact; a 5.0L OHV engine will always (and I do mean always) be substantially smaller than a 5.0L DOHC engine. It's simple design, the DOHC engine has 3x more camshafts, more timings chains, more sprockets, more lifters, more of everything. This stuff takes up space. Every piston engine requires pistons, rods, a crankshaft, that will be the same either way, but the OHV engine will be more compact on the top end.

As for You really don't have to look farther than a comparison of LS1 f-bodies and mod-motor mustangs to realize the fallacy of your remarks. LS1 Camaros can get 30mpg highway when equipped with the T56, and make quite a good deal more power than the DOHC mustang engine. The reason the Camaro has more displacement is because the OHV engine allows for more piston bore and stroke length than the "sophisticated" DOHC design.

I hope that you haven't fallen prey to the import lover argument of "more HP/Liter", which is not taking into account the external dimensions of engines. The Northstar engine is dead, the small-block chevy lives on, that should tell you something. Put direct injection on a LS3 and you've given it another 10-20 years of competitive performance.

IF DOHC is such a poor design that GM is one of the only ones still making it? It is not good enough for everyone else but Dodge. The push rod engine is cheaper to build. Hmm. I just wonder why it is the two push rod kings were still making excuses for building push rod engines? Could it have been the lack if money??

You want a good example? The new Camaro has a V6 that makes 304 HP on 3.6 liters vs a 6.2 V8 that makes 426 Hp in top form. It is not all direct injection here. The Northstar was killed more do to cost. Even the V6 in the Camaro was a concern do to cost. DOHC is just more expensive in a V style engine and cost is the prime factor.

The fact is the push rod V8 is still around more to the fact it is cheaper to build. Less parts.

I will give you that GM has done well for a long time with the puch rod and the LS engine is a good engine. But time is running out. You can argue with me but when the other companies start to move back to push rods I will tell you that you were right. But how many push rods are in development with any of the other companies? Do you see a great move back to push rods? Is GM the only one that is right and everyone else is wrong?

I think you need to be prepared as I expect GM to move away from push rods soon in the V8. THey have already done so with the Truck Diesel.

Believe me I would rather see the LS engine continue as I make a lot of money off those engines. When Ford the loss of the 5.0 hurt. But I stopped buying the lie along time ago and know the companied need to be more efficent with there engines or we will not have any kind of performance with the new goverment rules.

[Drew Dowdell]

I don't think anyone is claiming that DOHC is a poor design, heck it's been around longer than the pushrod! We just don't see the end of the pushrod just yet. GM hasn't yet added 3 valves per cylinder, VVT, or DI to the LS engine. There is still some life left to it.

[hyperv6]

IF, through some government mandate, there is a shortsighted restriction on engine displacement, then yes, I could see the Corvette being forced to move to a smaller displacement DOHC setup. But until such a restriction exists, there is no reason for the engine to change configuration.

BTW, DOHC has been around in production cars since 1928. The Cam-In-Block pushrod configuration that we know today was released in 1949.

So which car is using the older technology again? Porsche or Corvette?

The new 911 is not anything like the old engine other than it is a flat 6.

The restrictions are coming in higher MPG and lower emissions. These are killers of large displacment engines.

[hyperv6]

I don't think anyone is claiming that DOHC is a poor design, heck it's been around longer than the pushrod! We just don't see the end of the pushrod just yet. GM hasn't yet added 3 valves per cylinder, VVT, or DI to the LS engine. There is still some life left to it.

They will buy time with the DI but I do not expect the 3 valve.

I suspect the new GM will move ahead with a smaller displacment V8 that will be for the trucks but adapted to the Vette and Cadillac on the top sedan. I saw a whle back Tom Wallace mention they were looking at smaller diplacment and if they were I do not expect them to be push rod.

They will stay with the LS for a while just because they are so far behind on a new engine. I think we may be into the C7 a couple years before we will see a new engine around 2016-2017.

They are now working on the duel clutch.

Tom also said they were looking into a smaller and lighter car. Since he is retired I suspect some things will change a little but with the future rules I suspect the future Vette will be smaller in several ways.

[Drew Dowdell]

The new 911 is not anything like the old engine other than it is a flat 6.

The restrictions are coming in higher MPG and lower emissions. These are killers of large displacment engines.

The newest LS engines are basically all new. They don't have anything in common with the older ones other than they are cam in block.

The Corvette still gets some of the best mpg for the amount of horsepower it makes. I don't think a DOHC engine that makes the same horsepower would get much better mileage.

There is still D-o-D, DI, VVT, 3 valves per cylinder out there.

[Drew Dowdell]

They will buy time with the DI but I do not expect the 3 valve.

I suspect the new GM will move ahead with a smaller displacment V8 that will be for the trucks but adapted to the Vette and Cadillac on the top sedan. I saw a whle back Tom Wallace mention they were looking at smaller diplacment and if they were I do not expect them to be push rod.

They will stay with the LS for a while just because they are so far behind on a new engine. I think we may be into the C7 a couple years before we will see a new engine around 2016-2017.

They are now working on the duel clutch.

Tom also said they were looking into a smaller and lighter car. Since he is retired I suspect some things will change a little but with the future rules I suspect the future Vette will be smaller in several ways.

I hope we don't get the shortsighted goverment restrictions on engine displacement. That's what the Euros have done.

The previous generation Malibu V6 would get better highway mileage than the Camry 4-cylinder because it had better torque at a low RPM. Displacement doesn't always mean poor mileage.

[smk4565]

SMK Go to this Site Look at where the Corvette ranks and Shut the F*** up for once. Your wrong! The Vette uses leaf springs and push rods yet it still tops the list for fractions of the price. http://www.fastestlaps.com/track2.html

The ZR-1 only beat the GT-R by 0.3 seconds and it costs $50,000 more. The Z06 which costs the same as the GT-R was 16 seconds slower. So faster at a fraction of the price doesn't hold up against the GT-R, plus the GT-R has a back seat.

The Koenigsegg doesn't post a great Ring time because it loses grip in corners, and is designed for top speed and straight aways. The Koenigsegg can go 245 mph but on a tight track like the Nurburgring it is at a disadvantage. The CCX originally didn't have a spoiler either, since the CCX was only .5 seconds faster than the CCR, I am guessing that is a no rear spoiler car. Put a spoiler on the back and it would cut that lap time down a lot.

[smk4565]

why not a 4 litre, 500hp pushrod motor? that would be real innovation. or push the envelope and try to perfect the camless engine.

of course in that scenario, a camless engine i would prefer to go rwd. keep the car small and light.

corvette may need an 8 speed auto or dual clutch thing some day too.

1. Not possible, and GM only got 200 hp from 3.8 liters, getting 500 from 4.0 liters will be a challenge.

2. I agree with staying rear wheel drive.

3. They need dual clutch, maybe 7 gears.

Someone brought up Ecoboost. An example is the 3.5 Ecoboost makes about 360 hp and 350 lb-ft depending on the car it is in, and the Silverado 5.3 liter makes 315 hp and 338 lb-ft. Smaller displacement turbo engines are going to replace really big displacement engines. GM needs to realize that sooner, rather than later, especially to hit CAFE. The Silverado should get turbo V6 gas and diesel engines to replace the 4.8 and 5.3 V8s.

[Drew Dowdell]

1. Not possible, and GM only got 200 hp from 3.8 liters, getting 500 from 4.0 liters will be a challenge.

2. I agree with staying rear wheel drive.

3. They need dual clutch, maybe 7 gears.

Someone brought up Ecoboost. An example is the 3.5 Ecoboost makes about 360 hp and 350 lb-ft depending on the car it is in, and the Silverado 5.3 liter makes 315 hp and 338 lb-ft. Smaller displacement turbo engines are going to replace really big displacement engines. GM needs to realize that sooner, rather than later, especially to hit CAFE. The Silverado should get turbo V6 gas and diesel engines to replace the 4.8 and 5.3 V8s.

You're full of it basing your estimates of what can and cannot be done from an engine that, while many here appreciate, is admittedly very old tech. The pushrod 3.5 also did 200hp with no great leaps in engineering.

I'd be curious as to how big the exterior dimensions of the 3.5 liter ecoboost are compared to the exterior dimensions of the 5.3. I'd guess they are roughly the same. Which means that the 6 liter could also fit in the same physical space, making your ecoboost point rather moot.

[cletus8269]

The ZR-1 only beat the GT-R by 0.3 seconds and it costs $50,000 more. The Z06 which costs the same as the GT-R was 16 seconds slower. So faster at a fraction of the price doesn't hold up against the GT-R, plus the GT-R has a back seat.

The Koenigsegg doesn't post a great Ring time because it loses grip in corners, and is designed for top speed and straight aways. The Koenigsegg can go 245 mph but on a tight track like the Nurburgring it is at a disadvantage. The CCX originally didn't have a spoiler either, since the CCX was only .5 seconds faster than the CCR, I am guessing that is a no rear spoiler car. Put a spoiler on the back and it would cut that lap time down a lot.

i wonder if the GT-R's AWD has something to do with that?

maybe watch this video

and to make things clear, dont forget the fact that the GT-R that is .3 seconds slower is the SpecV, you know the $160,000 thats only available in japan...

see for yourself.

[hyperv6]

I hope we don't get the shortsighted goverment restrictions on engine displacement. That's what the Euros have done.

The previous generation Malibu V6 would get better highway mileage than the Camry 4-cylinder because it had better torque at a low RPM. Displacement doesn't always mean poor mileage.

I don't expect the goverment to put in size restrictions. The rules they have in place are already doing the job for them. Engines will have to be smaller because of the jumps in MPG snd Emissions.

The plain simple fact is we will have to get more from less. Also remember the engines we will use are not just for here in the states but also will be used world wide. So in some way the size issue elsewhere still may play into to this. It is a global company.

I know the LS is not the old Small Block. It shared bore spacing and that is about it. Just as the 911 flat six. It is no longer the air cooled wonder it once was.

I just ask if push rods has such a great future why are few if any are working to make them? There are reasons all these companied are spending more money on the new engines andnot just because they want to.

Also an example that we are not going to have to do more with less is Aston Martin and BMW beating a path to the Toyota IQ platform? Cars are going to shrink world wide with this green crap. It has them all scared no matter the maker.

[Drew Dowdell]

i wonder if the GT-R's AWD has something to do with that?

maybe watch this video

and to make things clear, dont forget the fact that the GT-R that is .3 seconds slower is the SpecV, you know the $160,000 thats only available in japan...

see for yourself.

You don't seem to understand, in SMKland, if it doesn't have DOHC, it doesn't matter if it beats the competition in every single test, it still loses.

[Drew Dowdell]

I don't expect the goverment to put in size restrictions. The rules they have in place are already doing the job for them. Engines will have to be smaller because of the jumps in MPG snd Emissions.

I just ask if push rods has such a great future why are few if any are working to make them? There are reasons all these companied are spending more money on the new engines andnot just because they want to.

I see where you're going. I think the death of the pushrod V6 was brought on more by the advances in 4-cylinder technology. I think we'll see more ecoboost type 4cylinders in the very near future and we're unlikely to see many, if any, more small displacement V6es of any kind. I'll take a stab and say that 3.5litres will likely be the new floor for new V6 engines. Any V6 coming out, not in development today, will be 3.5 liters or larger.

I think the same effect will happen on V8s a bit further down the road. Ford is already proving that with the ecoboost V6es. The problem here is that 4.0 liters is likely the largest Ford can go on an ecoboost V6. This is where the pushrod comes back into play.

There is no reason GM couldn't turbo or supercharge a medium displacement pushrod V8. The 5.3 puts out 315hp today as a naturally aspirated engine. GM could throw a supercharger on that very easily and have a 400+ hp engine that will fit in the space a N/A DOHC engine could fit. Turbos and DOHCs take up a lot of space remember.

[smk4565]

The Ecoboost's main benefit over the 5.3 V8 or Ford's 4.6 V8 is gas mileage. Rather than a 15/19 mpg V8 pickup, they can have a 16/22 mpg pickup with more power and torque. Small displacement V8s with turbos and all the latest technology can be used for the 400-500 hp engines while still meeting the government regulations.

[regfootball]

I hope we don't get the shortsighted goverment restrictions on engine displacement. That's what the Euros have done.

The previous generation Malibu V6 would get better highway mileage than the Camry 4-cylinder because it had better torque at a low RPM. Displacement doesn't always mean poor mileage.

don't be surprised if we see displacement limits in the US soon. overall, they seem to be pushing eveyrthing about this country towards a european model....although the colonists moved to get away from 'the european model'.

[regfootball]

I see where you're going. I think the death of the pushrod V6 was brought on more by the advances in 4-cylinder technology. I think we'll see more ecoboost type 4cylinders in the very near future and we're unlikely to see many, if any, more small displacement V6es of any kind. I'll take a stab and say that 3.5litres will likely be the new floor for new V6 engines. Any V6 coming out, not in development today, will be 3.5 liters or larger.

I think the same effect will happen on V8s a bit further down the road. Ford is already proving that with the ecoboost V6es. The problem here is that 4.0 liters is likely the largest Ford can go on an ecoboost V6. This is where the pushrod comes back into play.

There is no reason GM couldn't turbo or supercharge a medium displacement pushrod V8. The 5.3 puts out 315hp today as a naturally aspirated engine. GM could throw a supercharger on that very easily and have a 400+ hp engine that will fit in the space a N/A DOHC engine could fit. Turbos and DOHCs take up a lot of space remember.

GM never invested in making their pushrod v6 keep up in refinement. i actually would love to see them take a stab at an all new 3.8 litre compact, aluminum, 60 degree pushrod 6. but they would have to obsess about the overall quality of it to a degree that they never gave a $h! about in the old pushrod 6's. aluminum, DI, 4 valves, VVT, smoothness, ability to rev high, high end power, etc.

[Drew Dowdell]

The Ecoboost's main benefit over the 5.3 V8 or Ford's 4.6 V8 is gas mileage. Rather than a 15/19 mpg V8 pickup, they can have a 16/22 mpg pickup with more power and torque. Small displacement V8s with turbos and all the latest technology can be used for the 400-500 hp engines while still meeting the government regulations.

That would be quite the accomplishment since the Taurus SHO is barely managing 22mpg highway as it is, I don't think fuel mileage would improve by putting it in an F-150.

[hyperv6]

I see where you're going. I think the death of the pushrod V6 was brought on more by the advances in 4-cylinder technology. I think we'll see more ecoboost type 4cylinders in the very near future and we're unlikely to see many, if any, more small displacement V6es of any kind. I'll take a stab and say that 3.5litres will likely be the new floor for new V6 engines. Any V6 coming out, not in development today, will be 3.5 liters or larger.

I think the same effect will happen on V8s a bit further down the road. Ford is already proving that with the ecoboost V6es. The problem here is that 4.0 liters is likely the largest Ford can go on an ecoboost V6. This is where the pushrod comes back into play.

There is no reason GM couldn't turbo or supercharge a medium displacement pushrod V8. The 5.3 puts out 315hp today as a naturally aspirated engine. GM could throw a supercharger on that very easily and have a 400+ hp engine that will fit in the space a N/A DOHC engine could fit. Turbos and DOHCs take up a lot of space remember.

Yes the 4 and V6 engines will be kept smaller and Turbo's with DI will be very common. Borg Warner is working hard with many MFG for many new Turbo engines. The VVT, DI and Duel Scrolled turbo's have little lag and are great for low end torque. My 2.0 is at 315 ft lbs and is a fairly flat curve. THe V6 DOHC is going to be the new V8 in the industry and Small Tubo 4 cylinders are going to be everywhere. V6 Turbo's will not be rare.

I see the same for the V8. The key though is the turbo will work better with more breathing and more RPM. I could see some 4.0-5.0 V8 engines with Turbochargers. These could be used in light trucks the Vette and Cadillac sedans. But if they do a new engine. I just don't see it without 4 valves.

I know that Ford has looked at the Turbo V6 for the light trucks but killed it as they are affraid to give up the V8. But to keep the V8 they need it to be more efficent. Chevy and Dodge are in the same boat. They are going to have to get more from less to meet the MPG. The only way to do that is to be more efficent.

If it were not for the higher cost of DOHC already GM would have given it up a while ago. If I recall the LS not only was designed to have a 3 valve set up but it was designed in a way so it could be adapted to be used with a duel cam set up too at some point. This is part of the reason the bottom end is as strong as it is. The LS was made so it could be adapted to may other uses. But GM did not have the time nor money to do more than they did.

The LS is a cheap engine to build compared to the many other engines on the market. That fact is what keeps it alive and what kept the 3800 alive as long as it did. Just look how long it has taken GM to get a proper 6 speed transaxle. They could not wait any longer. Imagine many of these new Turbo engines with a six speed that keeps the revs up to keep the power up when you need it and a small displacment engine just for riding down the road. My 2.0 with a 4 speed is crying for the 6 speed it did not get.

[Drew Dowdell]

The LS is a cheap engine to build compared to the many other engines on the market. That fact is what keeps it alive and what kept the 3800 alive as long as it did. Just look how long it has taken GM to get a proper 6 speed transaxle. They could not wait any longer. Imagine many of these new Turbo engines with a six speed that keeps the revs up to keep the power up when you need it and a small displacment engine just for riding down the road. My 2.0 with a 4 speed is crying for the 6 speed it did not get.

I'll give you that the 3800 was kept alive because it was cheap but part of that cheapness was the lack of development dollars. The LS series doesnt appear to be hurting for development dollars and has been kept at the top of it's game.

[smk4565]

20 years ago the Ford 5.0 liter V8 (which was actually 4.9 liters) made 150 hp. Today Ford's 2.5 liter inline-4 makes 175 hp. Technology will drive down engine size while increasing power and mileage. By the time they get to the Corvette C10, it may have a 400 hp, 4-cylinder, or it might be electric.

[Drew Dowdell]

20 years ago the Ford 5.0 liter V8 (which was actually 4.9 liters) made 150 hp. Today Ford's 2.5 liter inline-4 makes 175 hp. Technology will drive down engine size while increasing power and mileage. By the time they get to the Corvette C10, it may have a 400 hp, 4-cylinder, or it might be electric.

Actually, by 1985 the 5.0 was back up to 200hp and was at 225hp in 1988. Doesn't really change your point, I just have to always correct the record after you post.

[cletus8269]

20 years ago the Ford 5.0 liter V8 (which was actually 4.9 liters) made 150 hp. Today Ford's 2.5 liter inline-4 makes 175 hp. Technology will drive down engine size while increasing power and mileage. By the time they get to the Corvette C10, it may have a 400 hp, 4-cylinder, or it might be electric.

the reason for crappy hp and performance form 74 to basically 87 was lower compression ratios than before and of course choking emissions equipment that have in the last 10-15 years finally been improved enough so that there can be 1:1 displacement/hp numbers and beyond.

by the time the c8 comes around i am sure that ICE will more than likely be the minority on the roads.

Edited August 31, 2009 by cletus8269

[Justin Bimmer]

Corvette EPA Pollution Info:

(grams per mile)

NOx 0.04

CO 2.1

NMOG 0.07

PM 0.01

Smog-forming Pollution:

(pounds per year) 3.64

Greenhouse Gases Emitted:

(tons per year) 9.65

Porsche 911 Turbo

Standards

(grams per mile)

NOx 0.07

CO 4.2

NMOG 0.09

PM 0.01

Smog-forming Pollution:

(pounds per year) 5.29

Greenhouse Gases Emitted:

(tons per year) 10.18

WAAAAAAAAAAAAAAAAAAAAAAAAAA???? GIANT V8 makes less pollution then DOHC Porsche magical engine?

[hyperv6]

I'll give you that the 3800 was kept alive because it was cheap but part of that cheapness was the lack of development dollars. The LS series doesnt appear to be hurting for development dollars and has been kept at the top of it's game.

The truth is the development of the LS was not that expensive. They just took pretty much what they had and corrected its short comings. While it is not the same engine as the original small block it is based on the same ideas and concepts.

The savings was in the content of the engine. A GM engineer stated long ago with the less number of parts it kept the weight down as wll as the price. 1 cam vs 4 cams, 16 valves vs 32 valves, less aluminum etc. This is a case where less parts is less cost over how many vehicles that has a LS engine in the 90's to date. That is a incredible savings for a cash poor company.

Lets face it GM saved money on all their engines in the last 25 years accept the Ecotec. They did pony up the money on it since it was used in so many cars around the world and they could not skimp out on it in Europe.

[z28luvr01]

If you consider the huge aftermarket for the LS engines, I think it is safe to say that the limits to their capabilities have not yet been reached. Direct injection and VVT are not yet used, and forced induction is only in its infancy. Consider the possibility of a 5.0 or 5.3 LS-based engine with direct injection, VVT, and a turbo. It's not unreasonable to expect around 450hp out of it, and in a 2800-3000 pound C7, 30+mpg highway is possible if not a certainty.

Again, while a DOHC V12 is a nice idea that should be done at GM at some point, I don't think it has a place in the Corvette. The current formula works so damn well, why change it? Put the V12 in a Cadillac, either in a Cien supercar or in a *real* flagship.

[cletus8269]

If you consider the huge aftermarket for the LS engines, I think it is safe to say that the limits to their capabilities have not yet been reached.

so, you seen this? i think it further backs you up...

[dwightlooi]

Wow, I stepped out for a couple of days and this thread exploded.

Anyway, let's clear up a few misconceptions shall we?

(1) All else being equal a DOHC engine is always bigger and heavier than a Pushrod engine. This is simply because the heads are much bigger and they have four times as many camshafts. If a DOHC engine of similar displacement weighs less it is a testament to its construction technology not the layout. With the same construction the Pushrod will be even lighter.

(2) Smaller displacement does not equal better fuel economy. The biggest determinant of fuel economy is vehicular weight, followed by gearing. Engine efficiency comes in third. And, engine efficiency is as much a function of internal friction as it is pumping losses. A DOHC 4-valve engine has higher internal friction and lower pumping losses.

(3) In general Pushrod engines have only one performance disadvantage compared to 4-valve DOHC designs -- they have smaller valve areas and do not breathe as well at high rpms. This disadvantage does not show itself until about 5300~6300 rpms. Below that, there is no performance disadvantage.

(4) The DOHC design has only one decisive advantage over pushrod engines when they are not tuned to deliver peak power at 6500 rpms or higher. Due to the lighter valvetrain mass, they tend to be be more refined at higher rpms. This affects consumer perception and consumer perception is often much more important than performance, economy or even cost.

[Chazman]

Interesting thread!

It's still looks like the C7's most likely motivation will be a Gen V 6.2.

One choice not here - which is still a remote possibility - is a turbo V6.

[regfootball]

Wow, I stepped out for a couple of days and this thread exploded.

Anyway, let's clear up a few misconceptions shall we?

(1) All else being equal a DOHC engine is always bigger and heavier than a Pushrod engine. This is simply because the heads are much bigger and they have four times as many camshafts. If a DOHC engine of similar displacement weighs less it is a testament to its construction technology not the layout. With the same construction the Pushrod will be even lighter.

(2) Smaller displacement does not equal better fuel economy. The biggest determinant of fuel economy is vehicular weight, followed by gearing. Engine efficiency comes in third. And, engine efficiency is as much a function of internal friction as it is pumping losses. A DOHC 4-valve engine has higher internal friction and lower pumping losses.

(3) In general Pushrod engines have only one performance disadvantage compared to 4-valve DOHC designs -- they have smaller valve areas and do not breathe as well at high rpms. This disadvantage does not show itself until about 5300~6300 rpms. Below that, there is no performance disadvantage.

(4) The DOHC design has only one decisive advantage over pushrod engines when they are not tuned to deliver peak power at 6500 rpms or higher. Due to the lighter valvetrain mass, they tend to be be more refined at higher rpms. This affects consumer perception and consumer perception is often much more important than performance, economy or even cost.

but if a good 4 cylinder DOHC motor can perform as well as an unrefined pushrod v6, and get better mpg......4 pistons vs 6, simpler and smaller block etc.......... which is why so many midsize mainstream cars now have the 2.5 litre size four popper. GM's big downfall was that they couldn't even make their value v6 run as well as the mainstream four bangers. either in smoothness or mpg.

[hyperv6]

If you consider the huge aftermarket for the LS engines, I think it is safe to say that the limits to their capabilities have not yet been reached. Direct injection and VVT are not yet used, and forced induction is only in its infancy. Consider the possibility of a 5.0 or 5.3 LS-based engine with direct injection, VVT, and a turbo. It's not unreasonable to expect around 450hp out of it, and in a 2800-3000 pound C7, 30+mpg highway is possible if not a certainty.

Again, while a DOHC V12 is a nice idea that should be done at GM at some point, I don't think it has a place in the Corvette. The current formula works so damn well, why change it? Put the V12 in a Cadillac, either in a Cien supercar or in a *real* flagship.

Most aftermarket items that add real power are often items that the facotry would not or could not offer. Cams that effect MPG and Emission etc. OR exhaust and intakes that would not pass drive by noise rules.

The most common change is a stroker kit to increase displacment. These kits are very common upgrades. The truth is GM has don most of the affordable and legal stuff. The ZR1 went to the supercharger as it was one of the few things left to do to get more air into the engine. The problem there is it is not a cheap mod and reallyt adds to the price of the engine if you do it right so it will hold up for warrant work.

[Drew Dowdell]

but if a good 4 cylinder DOHC motor can perform as well as an unrefined pushrod v6, and get better mpg......4 pistons vs 6, simpler and smaller block etc.......... which is why so many midsize mainstream cars now have the 2.5 litre size four popper. GM's big downfall was that they couldn't even make their value v6 run as well as the mainstream four bangers. either in smoothness or mpg.

Couldn't? or wouldn't?

On the mpg side of things, the previous gen Malibu V6 could get better highway mileage than a Camry 4-Cylinder.

I also wonder if the imports weren't playing to the test. Sure the 4-cylinders get good EPA scores for mpg, but who drives like that? Even the new EPA system is relatively conservative. You have to spin the hell out of the torqueless wonders that Honda produces even in just around town driving. We're lucky if we get 21mpg average (very typically 250 miles on a 12 gallon fill up) in our CRV. I can't imagine a 3.4 litre Chevy Equinox would be any worse.

[smk4565]

Due to the lighter valvetrain mass, they tend to be be more refined at higher rpms. This affects consumer perception and consumer perception is often much more important than performance, economy or even cost.

Bingo.

If the pushrod was so great, why does the CTS have a DOHC direct injected V6 rather than a pushrod V6?

I won't argue that the Corvette can get away with the pushrod V8 for another generation, maybe two, I am just saying it is better off with DOHC. Likewise for the GMT900s.

[hyperv6]

Couldn't? or wouldn't?

On the mpg side of things, the previous gen Malibu V6 could get better highway mileage than a Camry 4-Cylinder.

I also wonder if the imports weren't playing to the test. Sure the 4-cylinders get good EPA scores for mpg, but who drives like that? Even the new EPA system is relatively conservative. You have to spin the hell out of the torqueless wonders that Honda produces even in just around town driving. We're lucky if we get 21mpg average (very typically 250 miles on a 12 gallon fill up) in our CRV. I can't imagine a 3.4 litre Chevy Equinox would be any worse.

I just filled up yesterday. The 2.0 Turbo in my 3200 pound HHR got 23 MPG beating around town. No hypermiling. Just good all step on it till it feels good. It is more powerful and peppy than any V6 I have ever owned. In fact it is more potent than even many SBC and one BBC I owned.

Edited September 1, 2009 by hyperv6

[Drew Dowdell]

Bingo.

If the pushrod was so great, why does the CTS have a DOHC direct injected V6 rather than a pushrod V6?

I won't argue that the Corvette can get away with the pushrod V8 for another generation, maybe two, I am just saying it is better off with DOHC. Likewise for the GMT900s.

You mean something like this?

GM hasn't invested any money in pushrod V6es in a long time. That doesn't mean it can't be done.

[Drew Dowdell]

I just filled up yesterday. The 2.0 Turbo in my 3200 pound HHR got 23 MPG beating around town. No hypermiling. Just good all step on it till it feels good. It is more powerful and peppy than any V6 I have ever owned. In fact it is more potent than even many SBC and one BBC I owned.

I was comparing naturally aspirated to naturally aspirated, but if you want to go down the forced induction route the S/C 3800 and Turbo 3800 had a bit of kick around town and geared right could return good fuel economy. Investments into refinement could have made them very competitive engines.... but the car magazines demanded OHC or higher horsepower per litre.

The point I was making was that a pushrod V6 can be every bit as efficient as a 4-cylinder DOHC in a comparable vehicle. You don't have to put the spurs into the V6 Equinox to get around town like you need to with the CRV. The CRV revs high even in normal driving. If you keep the CRV revs below 3,000 like you can in an Equinox, you'll manage to piss off Mable Blue-Hair behind you in her LeSabre. If hearing the engine rev to 6,500 rpm smoothly is an important aspect in your car purchasing decision, perhaps a 160hp 4-cylinder AWD CUV isn't what you are looking for.