I have read many-a-posts about exhausts (turbo-back, cat-back, ect), but nothing about just doing the test pipe (remove the factory cat). These pipes can be had for under $100 w/o worry of triggerig the CEL (Ultimateracing.com). Has anyone dyno'd a stock Evo before and after a 2.5" test pipe?

 

i havent done it i have the buschur set-up but id guess youd gain 4- 5 hp tops and it would be noticeably louder but still fairly quiet. id save up and go with a full system if possible besides the power gains youll drop about 25 pounds of dead weight. that stock system is heavy.

 

I did this very test on a dyno, it was actually good for 8-10 WHP and the turbo spools faster. The exhaust noise does not seem to change much at all, and yes you will get a code, although it may take a while before you see it. The code does not seem to affect engine performance at all, it's just annoying to see the SERVICE ENGINE SOON light on all the time. You can get a simulator for the secondary O2 so you don't get the code. I am waiting on a PFC(2-3 weeks I am told), that will eliminate any and all potential codes from OBDII.

 

From what i saw you will actually loose some HP with a test pipe till you turn the boost back up with some boost controller - then you can make up to 10 extra hp at the same boost point (when you install the test pipe you loose some boost)

You can easily remove the cel bulb from the cluster

 

Al,

While I do not doubt that you saw this problem with your testing, but I cannot say that I experienced the same issue. I did not see the boost drop in my car when we installed a test pipe and the car was otherwise bone stock at the time. I cannot explain why this happened in your case, a couple other people I know have done this mod as well and did not experience any drop in boost presure.
I will be in your area all next week, I hope your car will be on the road at that time? I will give you a call when I am there.

Kind regards,

Eric

 

I've never heard of a turbo car that loses boost pressure when there is a decrease in exhuast back pressure. Can anyone explain why this seems to be the case with the EVO? Thanks.

Jesse

 

I believe the reason they are believing it's happening is becasue the ECU is throwing the car in some sort of safe mode. Therefor, dropping the factor boost to a lower level.

 

Must be the ECU as when I installed my turbo back with test pipe I had to turn down my MBC.