hayasa

Which part of the X's exhaust is the most restrictive? For instance, replacing just the axle-back would give you how much hp? Just Midpipe? Just Downpipe/O2 pipe? Anyone done any clear experimenting on this (keeping everything stock except for the piece being tested)?

SilverEvoX

iTrader: (2)

I'm pretty sure it's the 02 housing section. Secondly I'd say the test pipe if for no other reason because it helped spool up tremendously

evostang

I think it's a toss up between the muffler and cat.

I measured the factory system at 9.5 psi backpressure in the down pipe, like 8 inches in front of the cat.

Nobody has done pressure measurements of each component, and I suspect I'm the only one who has done the whole system. However, there are lots of dyno graphs from shops changing just one part vs the other.

Rguy

iTrader: (6)

The stock muffler for sure. It's really badly designed with respect to flow.

EvilEvo9MR

^^+1 believe it or not The stock muffler is usually the most restrictive part in an exhaust system

XxXtremeEvoX

pretty much everyone got it. O2 housing, cat, and muffler.

Rguy

iTrader: (6)

Check out the stock muffler and how many turns and chambers the exhaust has to go through.