cyborg1

Hi, I just attached a macs tune pipe to my TT pro .50 engine, and I get about 14.8k-15k rpms, which is pretty good. Question is, it comes on the pipe about half throttle until full thottle, but once i lower throttle below half, it goes off the pipe. Is the header too long or too short? On my os .25fx with a hatori pipe, there is no discernable drop in rpms, so i was wondering if the macs pipe needs to be tuned further? I didn't touch the header length yet. Thanks for the inputs!