GrandSport 2017

I don't see any reason why a production N/A 5.5L engine of a properly designed 4 valve configuration cant make 730 hp. Its all well within current technology. And in race form I'd expect even more power.

It really all depends on price point.
Can they get enough money for the car to cover warranty claims?
Can they put enough nannys in the engine management system to keep people from killing the engines? Like over revving them before the oil is 180 degrees? Inertia pushing the engine into over rev condition on a miss shift?

Its not a matter of if they can make 670 hp its a matter of if they can sell the car and warranty it with 670 N/A hp and still make money.

MitchAlsup

The 4.5 L F458 made 570 (595 in Specialé form).
570/4.5*5.5 = 696.
So, 700 HP is possible with 9,000 RPMs available. Maybe a we bit more.

I seriously doubt that 9000 RPMs will be found in a GM product.
At 8,000 RPMs you are going to be squeezed down to 620 HP.
At 7,000 PRMs you are going to be squeezed down to 540 HP.

RKCRLR

Inertia won't make acceleration continue. The revs start decreasing the instant the throttle is closed or the spark is cut.

BrunoTheMellow

Good luck missing a shift on a DCT . Shift denied shift denied shift denied.

CPhelps

In addition to the reliability warranty concerns you mentioned, GM also has federally mandated emissions and fuel efficiency to worry about, as well as their internal NVH standards, all of which will take a toll on power.

Rinaldo Catria

In any event, a 5.5L NA engine making 650+ hp regardless of FPC or not will not be the torque monster we have become accustomed to in the LT4 and 5. It will need to turn near 9000 RPM to make 650hp . At low rpm, it will be a bore IMO. This type of engine does work great with a DTC though. The quick shifting DCT keeps the engine in its narrower power band better than a manual could and used properly will prevent repeatedly bouncing off the rev limiter. Those high revs will take toll on longevity. I hope GM builds a war chest for warranty work for the track rats and street racers buying it. Just my 2cents.

BrunoTheMellow

The c8 is way too heavy for an NA engine. It's not going to happen.

Rinaldo Catria

You may be right. BUT, lets look at the possibility. My 2013 Audi RS5 has a 4.2L NA V8 making 450 hp @8250 rpm..(cross plane btw) lets apply that to the Vetts 5.5L.. 5.5/4.2=1.31 x 450 hp = 589.5.. now rev it to 9000....9000/8250=1.09... 1.09 x 589.5 = 642.5 hp.. now I think its likely that they can massage that up to about 700 hp with todays technology . and with low gearing in the first couple gears get sub 3 second 0-60 times in the 3700 lb Z06 while sparing the 8 sp Tremec DCT the torture it would be getting from ~650 ft lbs of torque it would be getting from a twin turbo setup. But this NA engine would be a snooze with a manual behind it getting punched in 4th gear at 65 mph. It wouldn’t start coming alive until 4,000 rpm.

BrunoTheMellow

Man. You won't see 9k out of a GM engine. Specially not at 5.5L. that's insane. Ford got 525 HP out of 8250 rpm at 5.2L.

PRE-Z06

Not saying it seems likely they go the NA FPC direction as much as I’d like them too, but you mention the GT350 which is heavier than C8 and has smaller CI engine, so even less torque and less torque multiplication from gearing that’s not as steep. What if this engine is a GS model instead of Z06?

blue_bomber697

I honestly have no idea why people think this is going to have an NA engine. This car doesn't just have to surpass the C7Z, it has to destroy it. It has to prove, that going mid-engine was the right direction for the chassis. We are not getting a 5.5L FPC motor that revs to 9,000rpm from GM. This isn't a GT3RS and its not priced like one. Not to mention all the potential problems that engine might encounter based on other large displacement FPC motors.

We have leaked documents showing a DOHC motor with twin turbo's... Given the power this car has to make due to its weight, it is a near certainty it will have forced induction. Almost everyone is going Turbo's and so will Chevy. I have no idea where the displacement will end up between 4.2L and 5.5L, or if it will be a CPC or FPC, but I can say with absolute confidence that it will be a DOHC Twin Turbo motor. That is just common sense at this point. There is no reason at all to think its going to be an NA motor.

WaxWeekly

It was said some time ago that there would be no 'Z06' and that only a GS would be available before the top of the line. While this may be totally wrong, it does stand to reason that if they call the next car a GS, it has to outperform a 460HP car instead of a 650HP car for the nameplate to show positive gains in performance.

IMO, the biggest shame is that GM sells a base model to everyone it can, knowing that many Corvette buyers will upgrade to higher performance variants as soon as they become available. Selling two or three cars to one person for each generation instead of one. This is a love/hate issue because it helps make the brand profitable, but makes us wait for variants later in the generation if we're not ready to buy a new car every year or two. There's no doubt in my mind that the design has multiple variants already near complete, but they string them out as part of their planned obsolescence business model.

I look forward to seeing the details for the version that I'll end up driving. It's just frustrating that I know it's 2 years away and waiting sucks.

MitchAlsup

Just a thought::

Let us postulate that the Z06 does have a 5.5 litre engine and because of the small displacement, it spins a bit higher (in the RPMs).
Because it spins a bit higher, it will not need a second shift in its 0-60 runs and could well come in at 2.65-2.7 seconds with only a
trifling more actual horsepower.

The faster the transmission shifts, the less a well prepared driver needs big TQ.

{Going to find a log to hide under.....}

23/C8Z

Well... I guess they can throw these in the trash?

BrunoTheMellow

As if GM would not capitalize on a hugely famous nomenclature.

WalterSobchak

I agree completely with this. Everything leaked previously has proven to be dead nuts on. So the twin turbo leak leaves me no doubt this will be it. Now maybe they go flat plane for the zr1 because there won’t be many produced who knows, but I believe z06 is the leaked tt cad based on the accuracy of everything previously leaked.

PRE-Z06

LT7 being a derivative of the Blackwing which they said wouldn’t be in the C8 makes sense and written by the same blog ironically.
https://gmauthority.com/blog/2019/07...tte-z06-leaks/

the lark

I was listening to the guys in the pits at the 24 hours of Daytona. Saying corvette was having vibration problems.
I’m predicting that they will go twin turbo 32 valve. Cross plane crank. No flat plane.
They can get plenty rpm, with that configuration.

Dominic Sorresso

Why wouldn’t the “vibration problems” have surfaced way before the actual race?

TxLefty

They would have. Speculation is fun: If they go NA, my guess is that the street engine will be of a larger displacement than 5.5, perhaps back to 7.0. So a 7 liter dohc version of the Blackwing, or something optimized for NA operation. The extra displacement would probably make the 670 possible without over stressing the engine to the point that the warranty is a concern and would be more tractable. The race car at 5.5 is fine since they are currently limiting the hp to something around 500 anyway. They are apparently getting that with a 16v.