MitchAlsup

Yes, I know of Pro Stock motors running 11K RPMs with push rods, too.
They are not warrented for 120K miles within emission limits either.

And rebuilt every weekend.

With good parts {Titanium con rods, forged pistons} yes. With typical high end GM parts, no.

A 3L DOHC V10 can/could do 20K RPMs (F1 from 2005 and earlier). Cosworth was working on one that would do 22K RPMs although reliability was questionable.

The 2.4L V8s are limited to using no more than 18K RPMs and have to last 4 race weekends.

JCtx

The new Vette started development during GM's bankruptcy and the worst recession in recent history folks, so forget about any ground-breaking engine. It'll be the same 6.2L we have now but with DI and maybe some other fuel-economy crap like cylinder deactivation, start/stop, etc. And you can also bet it'll be a C5.2 version (C6 is a C5.1). No ground-breaking stuff until the C8. Remember my words . The better interior (and techonogy) that is a must shouldn't be a problem, based on other current GM vehicles.

JoesC5

My point is that 10,000 RPM isn't out of the question. A production Honda S2000 had a redline of 9,000 RPM with a 3.4" bore X 3.3" stroke and carried a warranty. I doubt that a production engine would need to rev that high with forced induction though. A 3.31" bore X 2.75" stroke DOHC V8 would = 3L and 7500-8000 RPM would not be a problem in a production engine. Slap on twin turbos and 500+ HP would be easy, while meeting emissions and fuel economy standards.

tuxnharley

Maybe, maybe not. I believe my earlier point about torque not coming on until higher rpms is still valid. You're not gonna be able to gear that kind of motor to run 1600 - 2000 rpm at 70 mph like the C4/5/6s have done with both outstanding fuel mileage and flexibility.

In any case, this entire thread ignores the serious issue that has been discussed to death in other threads that a DOHC engine is taller, raises the hood line, affects aerodynamics, raises the cars CG, and just doesn't fit in the envelope provided by the Corvette design.

Nice theoretical discussion, but it ain't gonna happen!

JoesC5

The 4.5L 72 degree DOHC engine that GM has designed will fit into the same box that the LS series of engines fit into. No raised hood, no raised center of gravity, etc. It fits. The smaller bore(with closer bore spacings) and the block being made with CGI means the engine can be physically much smaller then the current LS series of engines to compensate for the larger DOHC heads. The twin turbos fit into the cavity between the heads so they can be assembled to the engine before it is put into the chassis. That 4.5L engine could be produced with a smaller displacement, say 4L or 3.5L or even 3L. Just reduce the bore and shorten the stroke. It's a lot easier to downsize an engine's displacement then to increase it. GM has been building the same small block engine from 4.3L to 7L.

My 2.3L supercharged Mercedes runs at 3000 RPM at 80 MPH, while getting 29 MPG. The C7 will have much better areo then my 1999 boxey 4 door sedan, along with being 200-300 pounds lighter, and a 3L V8 will have greater low end torque then my 2.3L engine which will allow them to gear the car higher for less RPM's on the highway, thus better gas mileage then my 29 MPG. In town, the smaller displacement engine will have much better gas mileage then a 6.2L V8. The forced induction is an 'on-demand' power adder, not like a large engine that has the large bore and stroke 100% of the time.

You keep forgetting that the supercharger/turbocharger will increase the engine's torque at the lower RPM's vs a NA engine, so it dosen't need low gearing at 70-80 MPH. Crusing along at a relatively low RPM, but when you need additional horsepower for passing/grades, the supercharger/turbocharger does the job but drops out when not needed. The supercharger/turbocharger gives the engine greater torque at low RPM's and the higher RPM's give the engine more horsepower.

I love the stump pulling 7L in my Z06, but things are changing. Smaller engines with forced induction are the answer.

Mike Campbell

Doesn't anyone remember those little Buick 2.8 liter V6's in the Grand National's back in the late 80's? They put those in those tanks and they ran like rockets. Plus, later they put those in the Pontiac Firebirds and they were the fastest stock Firebirds ever produced. Turbos can do wonderful things!!

JoesC5

I believe they were all 3.8L engines, and they were stout with their turbocharger. Even the NA 3.8L V6's were a pretty quick engine.

C6 Curtis

Sounds like an expensive engine to me!

Racer X

Why not just cut the small block in half, make it a v4 3 liter; boost it to 2 bar and be done with it. Plenty of room for turbos, can cut the length of the car by 9 inches, knock out 200 pounds plus, maybe 400 pounds with the aluminum frame. And because it has half the displacement and only 4 cylinders it will twice the mileage. It is all so simple. I can't believe the GM engineers haven't thought of it before. They must be complete idiots.


All of you guys are so much smarter than those GM engineers, and I have you all beat.










If you are buying that , I have this bridge to sell in Dallas. It is very new and little used. PM me for wiring instructions for my accounts in Nigeria, and I will put the title in the mail.

JoesC5

Do you know the history of the 4.3L V6? Or how about that slant 4 that Pontiac had in the early sixties, that was designed by GM engineers? Those dumb GM engineers thought about it(and did it) before you did. It looks like you are the one who got stuck with that bridge in Dallas that some Nigerian sold you.

Racer X

Yes, I am quite aware of the slant 4 and the 4.3 liter V6 (silly boys only cut of 2 cylinders, that made it need a funny crank). But neither is a V-4 and turbocharged to 2 bar. So they are not ahead of me.

Better get you bids in on that bridge quick, there is a lot of interest! I am the original title holder on the bridge. Nigeria just has better banking laws for my bridge endeavors. I may need some help getting the money out, if you just wire me some money for government bri... er, fees, I can wire the money to you, for a cut.

MitchAlsup

So does my Ferrari. Neither Honda nor Ferrari motors are inside the GM cost window for use in a Vette.

As the other gentleman noted: getting the torque such that one could cruise down the interstate at 1600 RPMs would basically/probably require a supercharger rather than a turbo.

JoesC5

A Honda S2000, with it's 9,000 RPM redline, costs less then a Corvette.

Two small turbos would spin up pretty fast on a 3L engine. A 3L engine in a 3000 lb car with a 28 Cd could easily cruise at 1600 RPM down the interstate, but even it was geared to run at 2,000 RPM, it still would get better gas mileage, especially in town vs a 6.2L NA engine. And a 7 speed gearbox would work better with the small engine vs the 6 speed behind 6.2L.

Since I drive a car with a Roots supercharger and an inner-cooler, I also vote for the supercharger. I like the way it preforms. My car has an electric clutch on the supercharger, so when in cruise mode, the supercharger's rotors are not spinning, thus no parasitic losses. But I suspect that the twin turbos are cheaper since they would be mounted between the heads(as with the 4.5L engine GM has designed). The turbo's housing's are cast integral with the exhaust manifolds.

Nice Ride

Not a fan of turbo's on a small cubic inch motor for Corvette. Larger cubic inch motor with no turbo is much less to go wrong for the same power.

tuxnharley

That just doesn't make any dimensional sense. A 72* V8 will have to be taller than a 90* V8 since the cylinder banks are closer together by 18* and thus more upright and taller. The DOHC cam gear will add on top of that. So - unless you have some specific dimensions/measurements to prove your point, I call

As for the low rpm torque/turbos - are you kidding about turbos nestled down in between the cylinder banks??? I think you forgot about the heat from the turbos/exhaust. That's the last place you'd want extra heat. Now if was a supercharger (like the ZR1, BTW) maybe so. Except, in order to have the instantaneous low rpm torque from a smaller displacement engine the supercharger would have to be geared to produce boost all the time, thus negating most of the fuel economy benefits of the smaller displacement.

Torque comes from displacement - either cylinder volume or FI of an equivalent amount. To have the low rpm flexibility and instantaneous response it needs to be there NOW, not later from either turbo lag or a supercharger clutch.

Don't get me wrong - I'd love for your theory to find a way to work out. I just don't see the height and torque issues being resolved as you say.

JoesC5

GM is the one that says their 72* 4.5L V8 fits in the same box as the LS series engine. GM designed their 72* 4.5L engine with reverse flow heads so that the exhaust ports are located where the intake ports are normally located. That allows them to place the turbos between the heads. The intake ports are located in the center of the heads and the ports pass through the valve covers. That means that there are no exhaust manifolds on the sides of the heads, making the "package" smaller. You forget that the intake manifold on the LS series of engines stick up well beyond the tops of the valve covers. While the DOHC heads are wider, the absence of the exhaust manifolds on the sides allow the engine to be no wider the the LS engine. While the 72* engine will be slightly taller over the valve covers of a 90* engine, having the turbos nest down in between the heads means there is no tall intake manifold as the turbos means you don't need the long intake manifold runners to produce low end torque. As far as heat is concerned, GM must not have agreed with you as they designed the turbos to fit between the heads. GM engineers designed the engine, not me, so why don't you call GM the BS'ers.

You are aware that the C6 was designed so a DOHC engine would fit into the engine bay, don't you? They called it a XLR and it had a DOHC engine. That's why the C6/XLR has a higher cowl height then the C5, to clear the heads,etc on the Cadillac Northstar engine.

On my supercharger, the computer reads my intentions via the accelerator pedal and if I push far down far enough, the computer applies 12 volts to the supercharger's clutch and within a couple of revolutions of the supercharger's rotors I have full boost being it's a Roots unit. When I'm cruising or needing low amounts of power, the supercharger is not turning, saving me gas. The supercharger is a 'on-demand" power adder, unlike a large engine that has the same displacement whether you only need 50 horsepower or 500 horsepower to preform the needed task. The displacement on demand systems do help in low power requirements, such as cruising on the highway, but for around town, they are deactivated. If Chrysler and GM thought they could run around town with 4 cylinders deactivated, they would have incorporated that into their design, but they didn't, so that means it's impractical under those conditions.

This is not some weird wet dream engine that I dreamed up, but an engine GM has desinged, built and tested. As far as I know it is tooled for production, as a twin turbo diesel, but the design, to me, could easily be converted to a gasoline engine.

Michael A

These are awful ideas.

*72 degree V8
*two Ecotec 4 cylinder engines put together
*a small block cut in half to create a V4

I want my Corvette to sound like a Corvette, not a John Deere tractor.

Michael

tuxnharley

Wow - sounds like a "great" engine for a Corvette. Remind me again - when did/will GM announce it for production.............. oh yeah, that's right, never mind.

There are so many things about this that make it impracticable for the Corvette that I hardly know where to start.

First of all, the C6 has a much lower front fascia and hood profile than the XLR. They may both start off at the same cowl height, but the C6 slopes down much more quickly and has a resultant lower Cd.

A twin turbo AND exhaust manifolds in the engine valley between the cylinder heads, under the SMC hood of a Corvette? I don't think so. Too much heat too close to the hood. Good luck with the paint and SMC warping.

Where is the intercooler going to be placed/fit on this kind of a set up in a Corvette? If the turbos are in the cylinder valley and right next to the intake, how does the intercooler fit in between? There is one for high RPM extended duration use in a Corvette right? ...............or, maybe not..............

Now for the really "good" stuff! Non cross flow heads? Siamesed intake and exhaust ports? Good luck with efficient intake and exhaust flow at higher RPMs. It will take the boost of the turbos just to make up for the losses in the intake flow.

Finally - I think your very last statement says it all - a diesel engine!!!
That might just work in, oh, say, a pick up truck with a higher hood clearance and a lower RPM demand curve, but in a Corvette?
Duh-oh!

Funny how you went from advocating small displacement 10,000 rpm engines and wind up touting a diesel as an example...........

Here's a pic of the exact engine you are touting. Doesn't look like that's a very low profile to me. Fit under the hood of a Corvette?
In the words of one of my favorite actors, Sam Elliott - "Ah doubt it"!

jackhall99

It's interesting to just sit back once in a while, read all the ****, enjoy a chuckle, and save my keyboard.

tuxnharley

Yeah, sorry Jack, but I just couldn't resist............... Jeesh!