Johnny77095

So it's been a while since this was updated... was any progress ever made?

Has anyone ever been able to lay hands on an M4 system to see what size pipe they use (that seems to be the most popular full system since it gives a solid 7hp gain across the board, when the bike is tuned).

If I can get the piping dimensions, I could probably fabricate one up myself using parts from summit racing (I've built several car exhausts that have turned out pretty nice). I'd just rather reverse engineer their system rather than do the trial and error method to get it tuned in.

I was thinking if I used the factory header pipes, and then upsize from a 1.5" factory pipe to a 1.75" midpipe, into a 2 into 1 collector that was 1.75" to 2"... throw a 1.75" crossover pipe about 6-8" up from the collector, and then flow into a 2"in, 2"out, 12" glass pack mounted about 18" back from the collector... that would give me along enough pipe to keep the bottom end, while the pipe diameter would increase top end and the crossover pipe would keep the "dip" from occurring in the mid-rpm's and widen the "power-hump" a little bit.

I am using "best-guess" engineering methods, rather than an a CFD and acoustic simulation software package. These engines aren't exactly high-tech, so I don't think it'll matter that much if it's not "perfectly tuned".

Honestly, the only reason I'm bothering to try this out is because the exhaust on this bike is wrecked beyond repair and I'm too cheap to buy an M4 or Yosh system for $750+shipping.

Anyway... if anyone has measurements on that piping, please, let me know.

Cheers.