I am new to Evo's, and plan to buy one next year. I used to have an SRT-4 and I was pretty familiar with all the parts on the car. Comparing the names used for that car and the names that are used for the evo are kind of confusing me.

SRT-4:
O2 housing: Section immediately after turbo, just before downpipe.
Downpipe/Racepipe/Testpipe: Section after the 02 housing, and before the catback. Downpipe meant it had a CAT, race/test pipe mean there was no cat.
Cat-back: Exhaust section after the CAT.
http://www.maxxfab.com/welcome1.html

EVO:
I was looking at the ultimate racing thread (https://www.evolutionm.net/forums/sh....php?t=336631), and it seems they offer a downpipe and testpipe/racepipe that a different sections in the exhaust. I also remember AMS working on a 02 housing, so the downpipe UR is offering isn't a 02 housing. On the Evo, what is the difference in the downpipe and race/testpipe? Any chance someone could make a dummy diagram like the one above?

Sorry for being a dummy about this.

 

hrm, 110 views and no reply's.

Glad I'm not the only one confused around here.

 

o2, DP, TP/Cat are all different components. If you have a Test Pipe then there will be no cat. And recently, I saw something about a one-piece DP and o2 housing, so in that case they won't be individual components.

This is the way I understand it...enjoy!

 

all the test pipe is is a straight pipe replacing the cat. from ultimate you can order the test pipe with a muffler, or resonator, or hi-flow cat I believe. I am pretty sure ams is working on the the o2 housing and downpipe as one unit to improve it, but as right now the down pipe and o2 housing are seperate components. A few vendors have said the stock downpipe flows really well so an aftermarket one could probably wait until you start hitting bigger numbers.