Exhuast back pressure

[TERRA Operative]

That's right.

Back pressure is simply a restriction to flow, and ANY restriction in an exhaust (past the restriction point at the merge) is ALWAYS a bad thing.

Once you have performed the merge at the headers, you cannot improve performance in any way by adding an exhaust. An exhaust pipe is simply there to allow the addition of mufflers and expel the gas in the safest way (no fumes in the cabin or burns from side pipes).

[Vios-GT_07]

^^

i actually learned this a while back, and i'm pretty sure OC said it... saying that though, wouldn't a straight through exhaust reduce back-pressure in the system as compared to, say, a factory muffler with its valves and maze type flow?

[TERRA Operative]

Yep, that's correct. The stock exhaust is that restrictive, that a straight through exhaust will be better.

You don't have to remove your exhaust for good flow, but the less restriction to flow it causes = better performance.

[trdee]

That's right.

Back pressure is simply a restriction to flow, and ANY restriction in an exhaust (past the restriction point at the merge) is ALWAYS a bad thing.

Once you have performed the merge at the headers, you cannot improve performance in any way by adding an exhaust. An exhaust pipe is simply there to allow the addition of mufflers and expel the gas in the safest way (no fumes in the cabin or burns from side pipes).

sounds about right there.