the dreaded exhaust question (again)

[Cloudsurfer]

Originally Posted by The Radium King

hi there, i'm asking the dreaded exhaust question (again). i've seached the forum but can't find what i'm looking for.

i'm new to the boxster and new to this forum - hello everyone ...

i have a 2000 boxster s. i am looking to increase power; i intend to do the chip/intake/plenum mods and was thinking about exhaust. sound is secondary and exhaust components (typically) expensive.

questions:

1) it makes sense to me that a freer-flowing exhuast will reduce torque at lower rpm (less back-pressure) but increase hp at higher rpms when more air is moving through; is this valid?

I'd say generally yes.

2) the boxster s has a more tuned exhaust, and aftermarket exhaust will yield a smaller (if any) hp increase; valid?

No, both cars use the same exhaust. 97-99 is one system, 00-02 is another, and 03-04 is different. Same from base to "S."

3) where is most power increase found - header, sport cats, test pipe (secondary cat delete) or muffler? i could see headers being most beneficial, as more power would be seen through efficiency (equal length pipes)?

Given how atrocious the stock headers are, I'd say the biggest gains are here.

4) if i am increasing/improving airflow at the intake with improvements to the intake and plenum, would these benefits be increased with a freer-flowing exhaust (more are in, more air out)?

Generally yes.

i quess i'm trying to drill down to whether exhaust mods are worthwile and, if so, which ones give the best bang for buck. and finally, whether a $76 ebay header is just as good as a $500 tuner header ...

Headers come in two varieties for these cars: "cheap" and "not cheap." Not cheap includes B&B, Supersprint, Cargraphic, Miltek, Tubi, FabSpeed, and a few others. Cheap includes the stuff on eBay for $100, and "discount" sites.

If you've ever wondered why good exhaust components cost so much, have a look at Burns Stainless (where most race teams and many exhaust manufacturers purchase components) and start pricing out what it takes to build a set of headers. Now add on R&D expenses, labor, and some mark-up so you can attempt to turn a profit, and there's your answer.