When looking into exhaust, should I be paying great attention to the length of the pipe? In order to improve exhaust scavenging?

Does anyone know what the "best" length for an overall system in 2.25" tubing would even be?

Im fairly sure that for the most part the length and diameter of the header play the largest role in scavenging. once the header scavanges the exhaust out of the cyilnder and goes to the exhaust the diameter and length do play an important role. you want somthing larger enough to be free flowing but not too big so that the exhaust pulses scavanged from the cylinder irratically bounce around in the oversize piping possibly hurting performance. The overall length will play a role in the powerband. the longer it is the more torque you will see down low and possibly hurt top end likewise the shorter it is the less bottom end torque you will feel accompanied by higher end power.

Pipe length adds pressure drop and will reduce the scavenging effect. The actual direction(the collector angle), flow rate, and diameter of pipe is the largest factors that generate the scavenge effect.
Of those, while flow rate(ft^3/s) will be constant for a given RPM, the diameter can be changed depending on how you build it. Both of these values will be used to calculate the velocity of exhaust gases, this value and the direction of the pipe collection is actually the most important to create the effect.


"Never argue with an idiot. They'll drag you down to their level, then beat you with experience!" -Anonymous

Re: Test pipe=Loss of torque?

See my comments on exhaust parts selection & pressure-wave chamber.


Go beyond the "bolt-on".