Flat Plane Crank

[Russ Noble]

Don't tell Jac Mac a smaller rod ratio is better! LOL

With the flatplane crank I was under the impression that the big power gains came from being able to equalise exhast pulses for each bank thus giving much better scavenge.

This is also achieved with crossover exhausts. Unfortunately with crossovers the primary pipe lengths wind up being too long to give the boost that the more optimum shorter pipes will give at higher revs. Hence the flat plane crank.

Lightweight internals don't give significantly more power but do give better acceleration which is a bonus. But if you can only run a short stroke flat plane crank because of balance problems then I would think a conventional big bore stroker would have more power and acceleration at much lower cost and complication. KISS is always a sensible goal. IMHO

Cheers