My main concern is about the cost of this as yet announced FPC street engine. For homologation reasons, they're going to need it to be a DOHC engine, if I understand the rules properly (correct me if I'm wrong, please). And it's the "small DOHC" part that I'm not keen on. Not how the crank is done. They're either going to need to shove this supposed DOHC into the trucks somehow, or give up and just say, "This is a bespoke engine for the ___ version of the Corvette." The former will keep the power train development costs in line, and therefore keep the resulting car's cost in line. The latter? That'll be C4 ZR-1 all over again from a pricing perspective. If not worse.

My prediction based on nothing other than educated guesswork is that: the Z06 will be a charged small block. The ZR1 will have the bespoke engine, and may actually have a loony price tag attached to it.

 

This is the vibration damper for the C8 LT2. It is the most critical component of this engine or any engine for that matter. You will never be able to spy on the damper in any top level race car. It is always covered. I can't even begin to describe how this component is designed. My thesis at uni was a V4 DOHC engine. ( Direct over head Camshaft) not double. As far as I know, nothing has changed other than CAD and materials. The FPC provides unsolvable secondry vibration or shake modes. What are those, you may ask? The advances in materials science allow a FPC V8 engine to live for a little while longer. It requires a vibration damper to mitigate very desructive forces. There are fancy computers trying to do this as we speak. Not even in the marvelous Porsche flat 6 or BMW inline 6s can this shake be eliminated. Damping or counter shafts do not eliminate these forces. The crankshaft alone absorbs these forces. They are very complex. So far, a 4000cc engine is the limit for a V8. Even then, no way can you thrash a F488 for much more than 40 000 miles. I mean thrash like you can a Vette. The 5.2 liter FPC V8 is not possible. There is no vibration damper that can prevent the concentric DCT clutch pack to explode sooner than the engine.
OK, i haven't designed an engine since 1968. Hopefully things have changed since then. Just saying.

 

Great post Shaka. First mod someone will come out with a solid aluminum flywheel to "save weight". Lol

 

So, are you thinking that Chevy will have a DOHC cross-plane engine for the production uprated C8s? AIUI IMSA rules say that the engine has to be homolgated off of a production *design*, and I think a DOHC design is sufficiently different from a pushrod engine that Chevy will have to release a DOHC variant for the Z06/ZR1/Zora/whatever?

Have a good one,
Mike

 

Just because its dohc doesnt mean it is a fpc...

 

Cool cutaway of the LT2 damper - this design is used primarily to quell vibrations from GM's DFM (cylinder deactivation which is now on all cylinders, not just V4 like the LT1).

Last comment is odd, Ford released the Voodoo in 2016 - an FPC 5.2 DOHC V8. So it is possible, but the Voodoo is known for oil consumption issues at this time.

 

The Voodoo engines are blowing up worse than the LS7. Lol

 

Links? I have seen certain oil consumption issues, but the most recent Ford V8 failures are the Gen 3 Coyotes.

 

I agree with you an so hope your right, I can see the FPC for racing but like someone else said we live in the lower end and need that torque down low and not have to keep it up to racing speeds to be able to use it.

 

I totally agree. It really comes down to cost.
A good example is lexus, with the LFA motor. It was exotic and cost way to much to use in any other lexus. I just hope the ZR1 doesn't cost 450k like the LFA.

 

The LFA is very pretty but it sort of stops there and at $388k base and up from there $450k being well within reach with the right options it is not even close to worth it even if I was a billionaire. I would not be surprised if the ZR1 went for an additional $30k over the C7 version but would really be surprised if more than that.

 

I suspect the FPC will have no issue putzing around town with correct gearing huge benefit of these modern super wide range transmissions

 

I wasn't referring to putzing around town, I was referring to spirited back road driving, that doesn't fit the full on track mode where waiting for the car to spool up the revs is not a big deal you just get it there and keep it there. I have another car with 330hp plenty of torque once you get into the power band but it takes a while to get there so when wanting to make a move requiring low end torque NOW you can't, and it's maddening. Another poster accurately referred to the S2000 being this way and driving him nuts waiting for the torque.

 

*Waiting for the HP* as the S2000 never makes any torque which drops off significantly on all engines above 5250 rpm, where HP continues to climb.

GM has always developed torquey engines with plenty of down low punch even while some enthusiasts demand more RPM and HP. Ford went that route with the Coyote and even further with the Voodoo. It can be compared to riding a 600cc Streetbike vs a 1000cc. One needs to stay in the high RPM in the 600 for any real power, while the 1000 can just crack the throttle and move out immediately (yes I've ridden both).

 

No, I was referring to the S2000's VTEC engine, which changes the cam timing at 6000 (?) rpm and makes a definite change in torque.

 

Correct, but even at that RPM, the 2.0l makes more HP than torque and carries onto to the 9000rpm redline as the torque, even with VTEC, significantly drops off at 7500rpm.

 

The Voodoo has a heavily counterweighted crank like a cross plane crank to subdue vibrations. That is counter to one of the flat plane crank advantages of reduced rotational mass and faster revving.

 

Agreed, but it allowed for a 5.2L V8 FPC. I don't know that it's possible without the countershaft, I suspect not. Good point I will explore further. I'm curious if it actually revs any faster now than the Coyote with a CPC.

EDIT: So far, all I can find is that the crank is 15% lighter than the Coyote's, but no info on countershaft weight.

https://www.motortrend.com/news/flat...ustang-engine/

 

Engine is still solidly connected to the wheels...not sure how you expect it to "spin up faster" other than increasing the amount of torque it produces along the whole curve...

 

Lower gearing, either at the diff or in the transmission. You've got to optimize the whole package for each type of engine design.

Have a good one,
Mike