Re: Update on 3.2ltr 16v turbo race car.
Posted: Mon Feb 09, 2026 11:31 am
I would anticipate that we'll probably just stick with the existing pistons. So it will be a bit low on the c/r side but as has been discussed, not really a problem that can't be surmounted by a little extra boost and the fact that the engine is virtually always running above x rpms. .Thom wrote: Mon Feb 09, 2026 2:37 am IIRC Duke started with a CR of 9.x:1 then gradually took it down to 8:1 along with fitting ever more aggressive camshafts, ending up with the torque "curve" of a supercharged engine - an almost straight diagonal line peaking at peak rpm.
I wouldn't consider anything higher than 9:1. As Tom said it is far easier to turn up the boost on a large turbo that will be more efficient with lots of boost and adjust the timing profile accordingly than being cornered with a high CR and little to no headroom. It's a race engine that needs to deliver between 5 and 8k rpm, who cares if it's a bit sluggish down low, which it even won't in a lightened race car.
Just my 0.02€.