Which engine for the C7 Corvette?

[dwightlooi]

Which engine will you prefer in the next Corvette?

[z28luvr01]

I'd stick with the small block V8 for the Corvette. It just works so damn well and has for all of its existence. Plus, the fact that the V8 consumes less will keep the Corvette from becoming a CAFE casualty. We know the C7 is going on a diet. If they can get it to around 2800-3000 pounds, even if they use the 6.2Lc at its current spec, it will result in an al around much better performing car.

The V12 would be perfect for a supercar in the mold of the Cadillac Cien.

[cletus8269]

v12s are for prancing horsey poony boys... besides, push rods are sexay hehehe

[loki]

i'd say the v8.

any chance the c7 will get "moderately lighter"? would a 350cuin motor making ~420hp be seen as a back step for corvette history.

i do realize if they used the current block it'd be heavier than need be, most likely. is the 5.3L able to be enlarged or is that set up for longer stroke?

is there any reason a new block should be made?

[loki]

The V12 would be perfect for a supercar in the mold of the Cadillac Cien.

yes, up the CR to make about another 30+hp....?

[Drew Dowdell]

The Small Block simply for packaging reasons.

[Robert Hall]

It will be interesting to see how the Corvette evolves from here..the C6 is awfully good all around in all it's variations..

[hyperv6]

Smaller and lighter is the way to go. Better MPG is important too in this car.

Also the key is which one would fit into the future Pick up truck line better.

V12 is a cool idea but not in todays market in a lower end sports car. When Pice is not an issue V12 when Cost and Price is an issue a shared V8 everytime.

The lighter engine will provide better balance anyway.

I would move some of the technology from the LNF turbo to this engine. If GM can get 145 HP per liter on the 2.0 liter LNF then imagine on a 6 liter V8.

Edited August 28, 2009 by hyperv6

[regfootball]

small block v8. but make it smaller and lighter. reduce displacement if need be.

add variable valve timing. direct injection.

bigger fish to fry is needing AWD. Nissan GTR and 911 have that.

Edited August 28, 2009 by regfootball

[dwightlooi]

A few things...

(1) A 5.3, 5.7 or 6.0 liter small block (the currently existing ones) are not lighter than the 6.2 and the 7.0 is not heavier either. They all hover around 198~212 kg. If you want to make the block lighter in general you want to make it smaller, that means you need to ditch the small block's 111.76 mm bore centers. Increasing or decreasing the stroke and bore do not change the weight tangibly, in fact it is accessories and the like which affects the model to model weight difference.

(2) A V-8 will be shared with trucks and other "muscle" cars like the Camaro. A V-12 will be shared with Caddy's STS replacement, etc. A V-12 is not particularly expensive if you use off-the shelf parts from the 3.0 V6 and simply mate two end to end. It'll may be add $3000~4000 more to the price of the car with the same profit margins. An S600 costs $120K not because the V-12 costs $40K more but because it's an S600 and they can charge $120K.

(3) In general, an in block cam V-8 has better power to weight or power to size ratio. A V-12 has higher power to displacement ratio, not to mention superior civility and prestige.

(4) Making the C7 slightly smaller and paying attention to mass will probably get it to ~3000 lbs (200 lighter than today). Adding DI and VVT to the LS3 will get you another 10% more output.

[hyperv6]

There is no place for even a small V12 in the future.

Also GM needs to go at least 4 valve in the V8. The excuses they have used since they could not afford the change over will no longer work.

They have done well with 2 valves but like sticking with the 4 speed Automatics it is time to get up to date. At least even for their image as being a up to date advanced power plant.

The smaller displacement will need more RPM and even a turbo to meet mileage and still make power. DI thrives with Turbocharging. Like I said if GM can get 145 HP per liter out of the Ecotec then imagine what they could do with a modern V8. THe variable timing would also suit the trucks as the computer would be tuned for the application it is in.

[smk4565]

It will be the same engines they currently have. Although the 7.0 liter may die off in favor of a 6.2 with a small supercharger for the Z06, and big supercharger for the ZR1, assuming the ZR1 returns. The engines will get recycled to keep cost down, and they have no other V8 to use because they canceled work on a new V8.

Personally I'd rather see a 4.5-5.0 liter DOHC V8 making 500+ hp for the Z06, and a 400 hp "detuned" version for the base model. Ferrari has a 4.5 liter V8 that makes 562 hp.

Actually, what I would like to see most is for Duesenberg to come back and blow all these cars away so America has the best car in the world again. The 1932 Duesenberg SJ has more torque (425 vs 424 lb-ft) than a 2009 Corvette. Why did Duesenberg 77 years ago have an engine as good as the Vette has now, oh right, they started using DOHC in 1929, the Vette isn't there yet.

Edited August 29, 2009 by smk4565

[loki]

Dwight, any knowledge of GM moving to 3 valve in the near future? that should add another 3-7% or so, right?

i think DOHC has it's place, but many here would like the simpler design for larger displacement and power....other than a few vette's, if it's a vette it needs CIB.

[Chevy Nick]

Where did these numbers come from? The HP estimate for a 6.2L gen 4 or gen 5 v8 with direct injection is way too low, that thing will easily pass 500 hp.

One of the disadvantages for the v8 is 'less output per liter'? Come on man, this is an enthusiast site, we all know that the small block chevy has one of best ratios of hp per external displacement. That v12 dohc monstrosity is going to take up a whole bunch of space.

Edited August 29, 2009 by Chevy Nick

[smk4565]

That v12 dohc monstrosity is going to take up a whole bunch of space.

They could fit a V12. The Mercedes SL and Aston Martin Vantage have V12s and they are similar size to the Vette. Although we all know there is about zero chance of GM making a V12.

[regfootball]

vette's have never had a v8, nor should they ever.

[ZL-1]

V8

[cletus8269]

They could fit a V12. The Mercedes SL and Aston Martin Vantage have V12s and they are similar size to the Vette. Although we all know there is about zero chance of GM making a V12.

with the v12 comes more complex repairs... i think we all remember the first generation zr-1. i recall hearing that there was a service bulletin that came out stating if a zr-1 came in for engine related service, it had to be boxed up and sent to mercury marine for repairs.

[dwightlooi]

Dwight, any knowledge of GM moving to 3 valve in the near future? that should add another 3-7% or so, right?

i think DOHC has it's place, but many here would like the simpler design for larger displacement and power....other than a few vette's, if it's a vette it needs CIB.

Not sure, but the 3-valve Single In-Block Cam design was actually tested but rejected for the LS3. The reason being that the increase in performance is not significant and not worth the additional complexity. The added valvetrain mass also lowered the redline.

More valves do not necessarily add power. It is increased airflow that makes more power and more valves simply facilitate that at high rpms. The problem is that a 2-valve head with lift at LS3 levels is adequate in supplying air at 6000~6300 rpms (which is where the power peaks in the LS engines). Going to a 4-valve or 3-valve head doesn't do much good unless you also optimise the cam profile for higher rpms. Herein lies the problem... the 6L80 transmission (which can handle 468hp/439 lb-ft) has a maximum shift speed of 6500 rpm. The 6L90 is even lower at 6000 rpm. Hence, if you want to have an engine which makes proper use of the advantages of a 4-valve head you need to develop a new tranny to allow it to rev to 7000 rpm or higher -- like GM's own LF1 3.0 liter V6 which makes 270hp @ 7000 rpm (90 hp / liter). Otherwise, a 4-valve head is just more bulk, more weight and more costs for very little benefit.

Think about it for a second a Camry V6 makes 268 hp out of 3.5 liters at 6200 rpm. That's 76.5 bhp/liter and not worth while using a DOHC-4v design for! An LS7 is already at 505 hp @ 6300 rpm out of 7 liters. That's 72 hp per liter. With DI we can probably get to about 75 hp/liter. Close enough. And not using DOHC saves globs of mass by eliminating the big DOHC heads, and three camshafts. You also make the engine smaller dimensionally so you can fit it into a smaller bay.

Edited August 29, 2009 by dwightlooi

[smk4565]

The Mercedes AMG 6.2 liter V8 weighs 438 pounds and puts out 493-525 hp depending on the car. The LS7 weighs 458 pounds and makes 500 hp, of course it is 7 liters. But the LS2 6.0 liter engine still weighed 448 pounds. The DOHC design isn't adding weight to the car, the Z06 would actually weigh less if they used Mercedes DOHC engine.

The Mercedes S65 V12 weighs 486 pounds, only 28 more than the Z06's engine, but look at the power the V12 makes. The S65 makes 738 lb-ft of torque only because they had to electronically limit it to prevent it from tearing the transmission apart. Without a limiter that engine makes 885 lb-ft of torque.

[hyperv6]

The reason I want the DOHC is efficiency.

The new engines will grow smaller in time We may still have a V8 but it will not be as large as it is today. By going to the DOHC it will improve the power per liter. Add to that a twin turbo with DI and VVT and you would have a power plant worty of a Ferrari. Base a truck engine on this design as well as a engine for Cadillac they could all support the cost and have a world class engine.

The LS line is amazing to make the power it does with a very inefficent engine as well as an engine that has yet to take advantage of VVT or DI yet.

GM threw tech into the Ecotech or 3.6 DI and it has paid off with a great little engines that can. Just put that effort into a V8 and it will make it viable for many vehicles even with the tougher goverment standards.

Besides how much longer will the lie that the 2 valve engine abd 4 speed autos are enough. GM bought time buy saying they were good enough but the truth was they just could not afford to go with the better technolgy.

[regfootball]

GM's pushrod v6's were universally panned for being too heavy (iron block), not as smooth at higher rpm as OHC mills, not producing as much hp/litre, not revving at quickly, and only limited to best power delivery at lower rpms.

now the vette and CTSv make great cases for v8 applications of pushrod power.

GM never opened the floodgates for pushrod tech and all the other goodies on a v6.

On an inline 4, its easy to do DOHC, you have only 2 cams, but then you don't have all the other pushrod gear that the PR engine has. Its prob a wash on the 4 but everything is overhead.

i think it would make sense for the corvette to have a DOHC v8 mill at some point. although, i think it would be like the CTSv, make the LS whatever the rare high perf version. the time may be soon where the corvette might function better to have a high strung 4.5 litre DOHC v8 instead of a big pushrod. But GM knows the pushrod v8 and it packages well into the corvette.

at some point the corvette will be perceived as stale with the character of its running gear. its brash and brute. but ultimately the rags will pass it of as old school etc. that point isn't here yet i don't think but it may come sooner than you think.

rather than examining the engine of the vette i think the more proper question is to question the character and capabilities of what corvette means. should corvette be this big wide gaudy huge car with a big v8? Or is something like the Lotus Evora or the size of a solstice or crossfire with a few more inches of leg room be more appropriate for the next decades of corvette existence?

For example, a stretched Kappa with a twin turbo 3.6DI that could do say 425 hp......assuming weight could be kept reasonable i wonder if they could make that work.

I do like the current corvette quite a lot and would gladly take one as an everyday rig. A base coupe with removable panel roof, and 6 speed manual, maybe with the upgraded suspension. I would love to travel cross country in one.

Edited August 30, 2009 by regfootball

[cletus8269]

once GM can right itself from all the ch 11 stuff i think the corvette will find itself in 1982, staring 1983 down with a reinvention a la 1984. i mean that was a huge leap going from a nearly 15yr old design

to

[cletus8269]

The Mercedes AMG 6.2 liter V8 weighs 438 pounds and puts out 493-525 hp depending on the car. The LS7 weighs 458 pounds and makes 500 hp, of course it is 7 liters. But the LS2 6.0 liter engine still weighed 448 pounds. The DOHC design isn't adding weight to the car, the Z06 would actually weigh less if they used Mercedes DOHC engine.

The Mercedes S65 V12 weighs 486 pounds, only 28 more than the Z06's engine, but look at the power the V12 makes. The S65 makes 738 lb-ft of torque only because they had to electronically limit it to prevent it from tearing the transmission apart. Without a limiter that engine makes 885 lb-ft of torque.

... i would tend to want to leave the Z06 out of this fight purely for the fact that most magazines say unless your name starts with "Ron" and ends like "Fellows" you will probably never have the skill for the Z06 to realize its full potential. the Z06 is a finicky track beast, and most will say that for the average joe a Z51 and for sure the ZR1 will serve the owner better due to the Z06's handling traits. with the new GS vettes... i'd say the days of the 7.0 Z06 are already numbered.

[smk4565]

GM's pushrod 4's died because they were uncompetitive and the imports had DOHC 4's in the 1980s that were better. Then GM's pushrod V6s died (except on the Impala/Lucerne) because the Imports have DOHC V6s through the 1990s and 2000s that are better. The pushrod V8 will die also, because right now, the imports have DOHC V8s that are better. GM uses the pushrods so they don't have to develop a new engine and because it is cheaper to make, they don't use it because it is a superior engine. But that is what led to GM's demise and bankruptcy. 20-30 years of being a step or 2 behind the competition and trying to pass off their mediocre product as being "good enough".

[cletus8269]

GM's pushrod 4's died because they were uncompetitive and the imports had DOHC 4's in the 1980s that were better. Then GM's pushrod V6s died (except on the Impala/Lucerne) because the Imports have DOHC V6s through the 1990s and 2000s that are better. The pushrod V8 will die also, because right now, the imports have DOHC V8s that are better. GM uses the pushrods so they don't have to develop a new engine and because it is cheaper to make, they don't use it because it is a superior engine. But that is what led to GM's demise and bankruptcy. 20-30 years of being a step or 2 behind the competition and trying to pass off their mediocre product as being "good enough".

oooookay so back to the corvette thing...

DOHC LT5 aluminum 5.7 L (349 cu in) small-block V8

405 hp @ 5,800 rpm

385 ft lbs @ 4800 rpm

Compression Ratio 11:1

Bore x Stroke 99 x 93 mm

LS6 aluminum 346 (5.7L) small block v8

405hp @ 6,000 rpm

400 ft lbs @ 4800 rpm

Compression Ratio: 10.5:1

Bore x Stroke: 99.00 x 92.00mm

but wait! theres MORE!

here is how the LS6 Z06 stacked up againts its THEN competition after going back to a pushrod motor.

0-60 mph 3.9 sec

0-100 mph 9.2 sec

0-100-0 mph 13.56 sec

1/4 Mile 11.9 sec

Skid Pad 1.03 G

Top Speed 171 mph (275 km/h)

Nürburgring Nordschleife Lap Time 7:56

BMW Z8

4.9 L 32 valve V8

400 hp

363 lb·ft torque

Motor Trend magazine achieved 0 to 60 mph in 4.2 seconds

Ferrari 360 modena

3.6 L V8

400 bhp @ 8500 rpm

275 lbf·ft @ 4750 rpm

0-62 mph: 4.5 s

porsche 996 911 turbo gt2

Engine 3.6L Flat-6, dohc, 4v/cyl, VVT, twin-turbo

444 hp

457 ft·lbf

0–62 mph 3.8 s

Top speed 190 mph

now... add to the fact that at the moment when you look at the ring times of the corvettes and then look around them to see the price range of the vehicles that are in the group... i'll be happy to take some rich yacht sailin nancy boy's lunch with my pooosh rodz dinosaur.

[Intrepidation]

Don't forget that the CTS-V makes more power with it's pushrod V8 than the M5 does with its DOHC V10.

smk is a glutton for punishment.

[z28luvr01]

Never mind the fact that pulling the buttery smooth superior DOHC inline 6 in favor of a coarse, unrefined, inferior LS1 V8 is actually a pretty popular conversion among BMW owners. I know that facts are useless when arguing with smk, but here's the evidence anyway.

[hyperv6]

oooookay so back to the corvette thing...

DOHC LT5 aluminum 5.7 L (349 cu in) small-block V8

405 hp @ 5,800 rpm

385 ft lbs @ 4800 rpm

Compression Ratio 11:1

Bore x Stroke 99 x 93 mm

LS6 aluminum 346 (5.7L) small block v8

405hp @ 6,000 rpm

400 ft lbs @ 4800 rpm

Compression Ratio: 10.5:1

Bore x Stroke: 99.00 x 92.00mm

but wait! theres MORE!

here is how the LS6 Z06 stacked up againts its THEN competition after going back to a pushrod motor.

0-60 mph 3.9 sec

0-100 mph 9.2 sec

0-100-0 mph 13.56 sec

1/4 Mile 11.9 sec

Skid Pad 1.03 G

Top Speed 171 mph (275 km/h)

Nürburgring Nordschleife Lap Time 7:56

BMW Z8

4.9 L 32 valve V8

400 hp

363 lb·ft torque

Motor Trend magazine achieved 0 to 60 mph in 4.2 seconds

Ferrari 360 modena

3.6 L V8

400 bhp @ 8500 rpm

275 lbf·ft @ 4750 rpm

0-62 mph: 4.5 s

porsche 996 911 turbo gt2

Engine 3.6L Flat-6, dohc, 4v/cyl, VVT, twin-turbo

444 hp

457 ft·lbf

0–62 mph 3.8 s

Top speed 190 mph

now... add to the fact that at the moment when you look at the ring times of the corvettes and then look around them to see the price range of the vehicles that are in the group... i'll be happy to take some rich yacht sailin nancy boy's lunch with my pooosh rodz dinosaur.

Note all the DOHC engines are smaller or much smaller doing nearly the same work. THe point is in the future we are not going to have 5.7-6.0-6.2 engines to make up for their lack of efficency with cubic inches. The Vette team will have to learn to do more with less.

I have 290 Hp and 315 ft lb with only a 2.0 GM engine. If they can do that with 2.0 imagine what they could do with 4.0 0r 5.0? Not only will it be powerful but it will meet the future demads of the EPA and CAFE.

As for weight and size of the engines. that is no longer true either. The guys who have swapped Northstars into Fiero's ahve found them to fit in as well or better than the LS engines and 3800SC engines. SO if some guy in a back yard can fit an DOHC engine low and in a small engine compartment I am sure GM can find a way.

The Key to the Vettes Future is the following.

Lighter! THis will increase performace, handeling and braking more any what you can do with and system improvment.

V8! No matter the engine it needs to remain a V8.

Front engine. Keep the engine up front. Vette guys wear this as a badge of honnor. GM has learned that and are fine with this as it helps keep cost in line.

Keep it affordable. While Vettes are not cheap the key to it has always been the sports car for the common man. If you can't by one new most can used. The last few years the performance has been on a scale that we never though they could do even in a base model.

Keep special models coming. GM in the past always had special limited cars for image and racing. ZL1, LT1, L88, ZR1 Z06 Etc. These often are not expensive to make but attract a lot of attention to the Vette and Chevy.

The last point of attracting attetion to Chevy is important. GM needs to show a little Vette in all their cars again. They need to show the same people who give us the Vette is are also the people who can give us quality cars in the entire line up. In the past the Chevelle, Nova and even the Impala had a little Vette in them. It may have been a shared engine, suspension part or styling que. The new Camaro has a lot of Camaro but the lines scream C6 in it overal effect. The styling makes a statment that I am part of this family. Of late most Chevy's have screemed we are Chevy and the Vette was adopted.

The Vette is to Chevy as the Blimp is to Goodyear. It should be brought closer to Chevy and not pulled away as it has been in the past few years.

Also incorperate Jake into all Special performaing Vettes. You have a cool Take No Prisoners image that could be made effective but do not make it a cheap sticker add on like it is on the special edition cars. The image on the intake of the ZR1 is the kind of touch ans where it should be used. Make the image mean something special mechanically was done and not to fool with me. It ain't bragging if you can back it up.

[smk4565]

Don't forget that the CTS-V makes more power with it's pushrod V8 than the M5 does with its DOHC V10.

smk is a glutton for punishment.

M5 is naturally aspirated and 1.2 liters smaller engine. Compare the CTS-V to the X6M turbo engine. The X6 M does 0-60 in 4.3 seconds (same as a CTS-V manual) and it is 5000+ lb SUV. The M5 may get a 600-625 hp V10, so it might blow everything away.

With DOHC BMW got 550 hp from a 4.4 liter, GM needed 6.2 liters to get that. DOHC makes more power per liter, and in this case, BMW's engine makes more low end torque.

Vette should be a DOHC V8, front engine.

Only 2 automakers still use pushrods, both filed for bankruptcy this year, hmmm.

Edited August 30, 2009 by smk4565

[Intrepidation]

The Viper is naturally aspirated and makes 600 horsepower. We can play this game all day.

[capriceman]

Would I be slapped for saying turbo direct injection 3.6 as a budget base sports car? since kappa was killed right? could we see a Corvette Sport?

[Intrepidation]

Also,

The CT-V gets 13 mpg / 19 mpg / 16mpg

The M5 gets 11 mpg / 17 mpg / 13 mpg

The CTS makes 556 hp and 551 torque

The M5 makes 500 hp and 383 torque

So let's review: The CTS-V with it's pushrod V8 is faster, more powerful, and gets better fuel economy than the M5 with its DOHC V10.

[Chevy Nick]

The Mercedes AMG 6.2 liter V8 weighs 438 pounds and puts out 493-525 hp depending on the car. The LS7 weighs 458 pounds and makes 500 hp, of course it is 7 liters. But the LS2 6.0 liter engine still weighed 448 pounds. The DOHC design isn't adding weight to the car, the Z06 would actually weigh less if they used Mercedes DOHC engine.

The Mercedes S65 V12 weighs 486 pounds, only 28 more than the Z06's engine, but look at the power the V12 makes. The S65 makes 738 lb-ft of torque only because they had to electronically limit it to prevent it from tearing the transmission apart. Without a limiter that engine makes 885 lb-ft of torque.

What's the external displacement of the V12?

Example: 4.6L DOHC engine on left, 5.0L OHV engine on the right:

Edited August 30, 2009 by Chevy Nick

[hyperv6]

Would I be slapped for saying turbo direct injection 3.6 as a budget base sports car? since kappa was killed right? could we see a Corvette Sport?

SMACK!

The Vette with a V8 base model is a cheap budget base sports car. Once you have the V8 in all of them it is cheaper.

THe V6 was rejected several times by GM studies of Vette owners just as mid engine has been.

[Chevy Nick]

Note all the DOHC engines are smaller or much smaller doing nearly the same work.

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

[smk4565]

The Viper is naturally aspirated and makes 600 horsepower. We can play this game all day.

With 8.3 liters. What would an 8.3 liter DOHC make? A Formula 1 engine is naturally aspirated and can make over 1,000 hp, although they limited revs to keep it to about 780 hp now. And that is from a 2.4 liter engine. Let's see a sub 3-liter pushrod make 750 hp.

[capriceman]

SMACK!

The Vette with a V8 base model is a cheap budget base sports car. Once you have the V8 in all of them it is cheaper.

THe V6 was rejected several times by GM studies of Vette owners just as mid engine has been.

what if they kept the c6 platform made it more contemporary looking added the v6 and changed the name. then have the C7

[smk4565]

Also,

The CT-V gets 13 mpg / 19 mpg / 16mpg

The M5 gets 11 mpg / 17 mpg / 13 mpg

The CTS makes 556 hp and 551 torque

The M5 makes 500 hp and 383 torque

So let's review: The CTS-V with it's pushrod V8 is faster, more powerful, and gets better fuel economy than the M5 with its DOHC V10.

The M5's engine was developed 5 years ago. Look at BMW's 2009 engines by comparison.

4.4L V8: 555 hp @ 6000 rpm, and 500 lb-ft @ 1500 rpm. (12/18 mpg, but that is in a 5200 lb truck)

An S65's 6.0 liter makes 612 hp and 738 lb-ft (electronically limited), so the CTS-V with a bigger engine gives up nearly 200 lb-ft. Pushrod loses.

[smk4565]

What's the external displacement of the V12?

Example: 4.6L DOHC engine on left, 5.0L OHV engine on the right:

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.

[loki]

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.

this is what a (the) Cadillac version should be....made like the vette, but make it priced and competitive to bmws, mercs, and such. aka more expensive in every right. the XLR, while unique was a very poor execution of a cadi vette.

[Chevy Nick]

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.

So that's your argument? anecdotal evidence that Aston Martin can do it, so can Corvettes.

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 a world-class sports car for the common man, affordable. The whole point of the Z06 is that it's faster than cars 3 times its price (same for ZR1). It's definitely not easy to make 505 hp, it's even harder to do it afford ably.

[cletus8269]

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.

hmmm MY arguement seems to lack anything said about that. in fact mine was that a $64K was able to hang with said world class sports cars... that up to 2x's the vette... but then i am from SC so i am behind the times...

by the way... here is a little tidbit for you. hard to believe aston martin just couldnt do anything with those cheap chevrolets...

[cletus8269]

Note all the DOHC engines are smaller or much smaller doing nearly the same work. THe point is in the future we are not going to have 5.7-6.0-6.2 engines to make up for their lack of efficency with cubic inches. The Vette team will have to learn to do more with less.

I have 290 Hp and 315 ft lb with only a 2.0 GM engine. If they can do that with 2.0 imagine what they could do with 4.0 0r 5.0? Not only will it be powerful but it will meet the future demads of the EPA and CAFE.

As for weight and size of the engines. that is no longer true either. The guys who have swapped Northstars into Fiero's ahve found them to fit in as well or better than the LS engines and 3800SC engines. SO if some guy in a back yard can fit an DOHC engine low and in a small engine compartment I am sure GM can find a way.

The Key to the Vettes Future is the following.

Lighter! THis will increase performace, handeling and braking more any what you can do with and system improvment.

V8! No matter the engine it needs to remain a V8.

Front engine. Keep the engine up front. Vette guys wear this as a badge of honnor. GM has learned that and are fine with this as it helps keep cost in line.

Keep it affordable. While Vettes are not cheap the key to it has always been the sports car for the common man. If you can't by one new most can used. The last few years the performance has been on a scale that we never though they could do even in a base model.

Keep special models coming. GM in the past always had special limited cars for image and racing. ZL1, LT1, L88, ZR1 Z06 Etc. These often are not expensive to make but attract a lot of attention to the Vette and Chevy.

The last point of attracting attetion to Chevy is important. GM needs to show a little Vette in all their cars again. They need to show the same people who give us the Vette is are also the people who can give us quality cars in the entire line up. In the past the Chevelle, Nova and even the Impala had a little Vette in them. It may have been a shared engine, suspension part or styling que. The new Camaro has a lot of Camaro but the lines scream C6 in it overal effect. The styling makes a statment that I am part of this family. Of late most Chevy's have screemed we are Chevy and the Vette was adopted.

The Vette is to Chevy as the Blimp is to Goodyear. It should be brought closer to Chevy and not pulled away as it has been in the past few years.

Also incorperate Jake into all Special performaing Vettes. You have a cool Take No Prisoners image that could be made effective but do not make it a cheap sticker add on like it is on the special edition cars. The image on the intake of the ZR1 is the kind of touch ans where it should be used. Make the image mean something special mechanically was done and not to fool with me. It ain't bragging if you can back it up.

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.

Edited August 30, 2009 by cletus8269

[smk4565]

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. 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.

I think the biggest switch should be dump the leaf springs and work on the rear suspension on the C7, and try to make the car not as wide. Engine should be DOHC V8, because with 5 liters, naturally aspirated they could have 400 hp, turbo or supercharger gets them over 500 hp. They could get more power out of it for a ZR1 if needed, but with GM cutting budgets, and crying about CAFE, etc, I wonder if the ZR1 will return on the C7.

Plus, if Cadillac wants to do battle with BMW, Benz, and even Hyundai, they need a DOHC V8 in the 4.4-5 liter range. And the F150 is getting a 400 hp DOHC V8 in the future, so the Silverado is going to look weak with it's 320 hp 5.3 liter and the 6 liter is thirsty.

[Drew Dowdell]

GM's pushrod 4's died because they were uncompetitive and the imports had DOHC 4's in the 1980s that were better. Then GM's pushrod V6s died (except on the Impala/Lucerne) because the Imports have DOHC V6s through the 1990s and 2000s that are better. The pushrod V8 will die also, because right now, the imports have DOHC V8s that are better. GM uses the pushrods so they don't have to develop a new engine and because it is cheaper to make, they don't use it because it is a superior engine. But that is what led to GM's demise and bankruptcy. 20-30 years of being a step or 2 behind the competition and trying to pass off their mediocre product as being "good enough".

Incorrect. In the 80's most import 4-cylinders on the economy end of the spectrum had SOHC not DOHC. GM actually mainstreamed the DOHC 4-cylinder before the imports with the Quad-4.

Toyota offered their first DOHC V6 in 1989 putting 151hp at 5200rpm and 159ft/lbs of torque at 4600rpm. This was roughly equivalent to the typical GM 3.1 litre pushrod of the day putting out 140hp (can't find the rpm) and 180ft/lbs with great low end torque. Just two years later GM introduced the 3.4 litre DOHC V6es putting out 210hp @ 5200rpm and 215ft/lbs @4,000rpm. Toyota wouldn't release a V6 that exceeded this horsepower rating for over 10 years. Honda has NEVER offered a DOHC V6 in an Accord, preferring to stick with SOHC. They didn't even bother to offer a V6 of ANY sort until 1994.

There were only 2 years since 1991 <1997-1998>where GM didn't offer at least ONE DOHC engine in a mainstream car .... but NO ONE BOUGHT THEM! Could it be something OTHER than DOHC humping was hurting GM at the time?

If the GM pushrod V8 sucks so bad, why is it that CTS-V drivers only get to see M5s in their rearview mirror and it took a Porsche of twice the CTS-V's price to beat it around the 'Ring?

If the GM pushrod V8 sucks so bad, why is it that the Silverado can out accelerate the F-150 and get better gas mileage while doing it?

[Drew Dowdell]

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. 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.

I think the biggest switch should be dump the leaf springs and work on the rear suspension on the C7, and try to make the car not as wide. Engine should be DOHC V8, because with 5 liters, naturally aspirated they could have 400 hp, turbo or supercharger gets them over 500 hp. They could get more power out of it for a ZR1 if needed, but with GM cutting budgets, and crying about CAFE, etc, I wonder if the ZR1 will return on the C7.

Plus, if Cadillac wants to do battle with BMW, Benz, and even Hyundai, they need a DOHC V8 in the 4.4-5 liter range. And the F150 is getting a 400 hp DOHC V8 in the future, so the Silverado is going to look weak with it's 320 hp 5.3 liter and the 6 liter is thirsty.

You seriously have no clue what you're talking about. Do you know that the leaf spring in the Corvette is not what you're going to find on the back of your dad's 1983 F-150? It's a high tech, fiberglass, transverse leaf spring that gives the Corvette so much of it's handling advantage.

A 5 liter DOHC with 400hp buys you.... what exactly? In the same packaging, you can get a 7 litre with 600hp. DOHC is a step backwards for the Corvette in overall performance.

[Drew Dowdell]

M5 is naturally aspirated and 1.2 liters smaller engine. Compare the CTS-V to the X6M turbo engine. The X6 M does 0-60 in 4.3 seconds (same as a CTS-V manual) and it is 5000+ lb SUV. The M5 may get a 600-625 hp V10, so it might blow everything away.

With DOHC BMW got 550 hp from a 4.4 liter, GM needed 6.2 liters to get that. DOHC makes more power per liter, and in this case, BMW's engine makes more low end torque.

Vette should be a DOHC V8, front engine.

Only 2 automakers still use pushrods, both filed for bankruptcy this year, hmmm.

you're getting a warn for this one. I'm tired of it.

Horsepower per liter is a RED HERRING!

[Drew Dowdell]

With 8.3 liters. What would an 8.3 liter DOHC make? A Formula 1 engine is naturally aspirated and can make over 1,000 hp, although they limited revs to keep it to about 780 hp now. And that is from a 2.4 liter engine. Let's see a sub 3-liter pushrod make 750 hp.

You CANNOT fit a DOHC 8.3 liter into the space a pushrod 8.3 liter can fit in. FACT!

[smk4565]

Honda's SOHC is a 4 valve per cylinder engine though, and it is still OHC, which has more benefits than OHV.

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.