TIV engine project

[70Turbobug]

Originally Posted by Wally

Hey Mark,

You really don't need the stock crank or want that always. More displacement is always a good thing: faster spool of a bigger turbo :-)
Personally I would limit the stroke at 78mm with type 1 rod journals (55mm) for optimum on stroke and strength.
Head flow and how much boost your engine can take will largely determine the max hp, the size of the engine only how much rpm it takes to get to full boost.
But I am sure you won't grenade the engine after start-up with larger strokes ;-)

I agree Wally,but my point is that you don't need a lot of displacement/stroke to make a lot of power.Your car is perfect example for that,and not to forget that you have unwelded heads! I'd be interested in what your ports look like
Let's say you were to use a 71mm crank instead of your 66mm it would be interesting to see just how much sooner your spool up is and at which psi the same 458hp would be achieved.