GM Confirms Corvette C8.R’s 32V 5.5L DOHC V8 Is A ‘Future Production-Based Engine’
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Yesterday, Chevrolet released technical details on the new mid-engine Corvette C8.R, confirming the race car has a dual overhead camshaft, 32-valve 5.5-liter V8 with a flat-plane crankshaft sitting behind the driver’s compartment.
Now, in an interview with automotive blog Jalopnik, the automaker revealed the race engine is “a future production based-engine,” although it stopped short of saying if it would appear in a future high-performance Corvette C8 model like the upcoming new Z06, for example.
While GM did not say if this engine is planned for a specific model, we reported last week that this engine is indeed destined for the C8 Corvette Z06, while a twin-turbocharged version of it will appear in the C8 Corvette ZR1.
For some more proof, FIA race regulations state that in order for a car to be eligible for the GTE class at Le Mans and other World Endurance Series events, at least 300 road-going versions must be produced. That means that a Corvette C8 with a version of this engine, which is not related to the LT family of V8s due to the camshaft placement, must enter production at some point if Chevrolet wants to take it to Le Mans or race it in IMSA-sanctioned events—which we know it will.
A GM spokesperson also told Jalopnik the DOHC V8 is not related to the Cadillac Blackwing engine family, nor is it based on any other current GM engine.
Just because the race engine has 5.5 liters of displacement doesn’t mean the production version of the engine will, we should note. The race engine measures in at 5.5 liters because that is the largest allowed engine size in IMSA/FIA competition, so it seems possible that the production motor could be larger. This is why the Corvette C7.R, as well as the 2010-2013 Corvette C6.R, had a 5.5-liter V8 as well, despite this new engine having no relation to the pushrod motor in the C7.R and C6.R.
LT2 V8 in the 2020 Corvette C8 road car.
We don’t want to get too carried away with speculation, but it also seems likely that the production version of the flat plane V8 destined for the Z06 will have more than 650 horsepower on tap. The C7 Corvette Z06’s 6.2-liter supercharged LT4 V8 had 650 horsepower, so GM probably wouldn’t released a next-generation version of the performance variant with less power.
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Source: Jalopnik
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Holy cow it is real! Merry Christmas!
Well there we have it folks.. a DOHC mid-engine Corvette. I can’t wait to see the reveal of the Z06.
This website has suggested long ago, that a large 6.2 liter DOHC version will possibly be used in the GM luxury SUV’s. The 5.5 liter race version could be shorter stroke and smaller bore of the the 6.2 DOHC to be offered in the 2021 Denali versions of the GMC Suburban types and various large Caddy SUV’s. Again, last year this website suggested HP ratings for the 6.2 DOHC twin turbo of 850 HP or even more. Any SUV that weighs close to 5,000 pounds or more, needs a huge amount of torque, especially for a high end luxury vehicle.
Can’t wait til Janurary when the C8R is raced at the 2020 Rolex 24 Hours of Daytona!See what it will do on that backstrech steep bank against the porsches&Ferraris?
Flat plane itself does NOT increase max rpm, revving, or HP. Flat plane V8 tend to be under 4.0 L – smaller engines rev faster. The Ford 5.2 L had so much mass added to the crank to quell the vibrations that the crank weighs about the same as the 7.0 L LS7! Ford went flat plane solely for the sound. Even Corvette racing never used a flat plane because there was NO benefit. The real benefit to a flat plane V8 is *low end* torque IF a variable volume intake manifold is used. Note how he said GDI was done for driveability – it actually lost 2% HP compared to PFI!
We’ve already heard it has a 97 mm bore and 93 mm stroke, for 5498 cc. It depends how wild GM wants to get with this engine. I don’t expect more than 565 bhp @ 7500 rpm (and 460 lb*ft). It is still supposed to be the super reliable, daily driveable super car. I would be more excited to see the Xtrac 6 speed sequential transaxle … over 200 lb lighter than the DCT.
I think that GM is doing it wrong with a 90 degree block and a flat plane crank. My understanding of the flat plane crank in a V engine is that it does not balance well and that is why the crank has to have more weight added in order to smooth out the vibrations. What I think GM should build is a boxer engine, like Porsche, Subaru, etc., and I’ll tell you why. One of the main desires in a racing car is to get as low a centre of gravity as possible. Common knowledge is that in a “single underhead camshaft” 90 degree V8, the engine COG is at about the same height as the in-block camshaft, or several inches above the crankshaft centreline. Put the four cast iron camshafts (in a DOHC engine) on top of the heads and up goes the COG. Not good in a race car. However, if the 90 degrees V is “stretched” out to 180 degrees, a “boxer” format, then the camshafts are at the same height above ground as the crankshaft. This drastically lowers the COG of the engine, and therefore the whole car. The GM boxer engine could use existing LS or LT cylinder heads, to keep the cost down in a street car, or DOHC heads for the homologation requirements of a race car. As an aside, a boxer engine makes it much easier for folding the hood in a convertible car, as the whole engine (in a mid engine format) is considerably lower than a standard V format. Think how well a C8 would handle with an eight cylinder GM boxer engine sitting behind the driver.