Quote:
Originally Posted by taxonomy  If you accept that it's pulse timing (do you?) that makes power in an after market exhaust and not a reduction in back pressure then you have to ask if logically part throttle will effect pulse timing. |
I think the majority of power gains in a full system aftermarket exhaust is due to the reduced back pressure. The tuning of the pipe is the little something extra that makes the better manufactures consistantly show higher gains with their systems over lesser known or cheaper brands.
A slip-on is mostly for sound and looks as you don't often see more than 5HP gains with them.