well, happily the car passed on its own, with flying colors. So I got the best of everything, no more rusty pre-silencer, no more disgusting fumes, and the tone is deeper. The scan didnt come up they way I wanted it,so Ill tell you the results : HC LIMIT: 2.00, tested: 0.95, CO limit: 30.0, tested 15.4, NOx limit: 4.00, tested 0.25. And there was no decrease in performance!

Yeah, I'm happy to hear about it since that is the exhaust setup I have in mind for my car, except that I want it in 3" pipe. Thanks for sharing info.

That is good that you passed.



I wouldn't go with 3" unless you are planning on making gobbs of power. You want the exhaust pulse to flow at high velocity, causing low pressure behind the pulse. This causes almost a vacuum that sucks the next exhaust pulse out of the rotor housing/cylinder.

3" would be compleatly useless, it would probably hinder performance if anything. Guys are making twice the horsepower and dont have 3".

my gtu with bonez cat passed with flying colors. probably helped that i had a giant vacuum leak :P

I have 3" piping and I gained a lot of power. So ur saying ifi went, like 2" I'd experience morepower?

He's talking about a non-turbo car.

My 91 coupe passed. It has a bonez DP and high flow cat and a RB cat back.

yeah a 3 inch exhaust is to much for a non turbo, if you had a turbo and were running more than 10 lbs. of boost then you would want a 3 inch exhaust, i used to have a 94 mitsubishi eclips GSX,it was the **** until i was stolen and wrapped around a tree, i had a 3 inch exhaust, bov, turbo timer, and a couple other nice,(NICE) goodies under the hood. only a turbo needs a 3 inch exhaust.ill shut up now i can talk about cars forever,piece!











waste ricers,all of them https://www.nopistons.com/forums/pub...IR#>/angry.png

I want to put 3" piping only for downpipe to the high flow cat because I'm planning to go for a street port on my next project while rebuilding the engine. I thought free flowing the exhaust right now wouldn't hurt anyway. Why would it be a problem to suck the exhaust out, technically speaking? Would it be because with peripheral exhaust, the intake mixture could be suck in the meantime?