UncleBuck

I have 2 gen2's. One with a ApexiN1 Universal and one with a HKS Universal setup. Both are cat-back with straight pipe at 2.25" and no scuba or resonators. The ApexiN1 system has more low-end power (pick-up) and gets better gas mileage than the HKS system!! Does anybody have any idea as to why this is??? I am thinking that it's because the HKS muffler has a larger inlet and outlet, but can that really make for that much of a difference?? Please advise.

fujita_TC

yes i think, because you are losing back pressure for having a larger inlet/outlet.

FromTheOld

It's all in your head. Unless you have any real numbers, it's all placebo effect and guessing. Changing one muffler, especially ones that have the same design (straight-through can), will do almost nothing for performance (especially because the only difference in this case is at the end of the exhaust system, for about 10-12 inches. That's nothing).

Less backpressure does not mean less low-end torque.

srb219

Intersting comment Old, but not true in my case. Running tusdo duals with Weapon R ram intake. Tusdo trumpets installed gained 1.75hp & 2.23 ft. lbs at 3000 RPM on dyno. Love the sound with trumpets removed but want the power gains more right now

Hypnotik_xB

Gains so little hardly prove your case. Infact are mostly just dyno variance as one dyno run will never be identical to another.

I agree with Old. Having a little difference in the inlet/outlet at such a small area in the end of an exhaust system will not have any effect.

FromTheOld

What's your baseline? Stock vs intake/tsudo exhaust, or intake vs intake/tsudo exhaust? Even then, 2 HP is nothing. I dynoed a car three times and it had more variation than what you had.

srb219

Baseline was everything idential except trumps. I love the sound without them but was concerned about back pressure/performance. Yes dyno runs do vary mainly because of engine heat etc. Base was with just warmed engine to temp. Next 2 runs with and without trumpets followed. 1st without, 2nd with