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Cats,Sensors, and Loud Exhaust

2K views 10 replies 5 participants last post by  hipo_wrx 
#1 ·
ok, im gonna get an uppipe with an cat and o2 bung if ones availible .they just check to see if all the emissions sensors and stuff are still working good here. i want a catless/sensorless downpipe and was wondering how loud this would be straight piped from the turbo back? anyone got a clue? or would this too cause a cel? and where would i get the proper resistor to get rid of the back o2 sensor?

this new car stuff confuses me but i can usually figure it out. my first new car to mod....if this doesnt work ill just go with my previous mod ideas. or if i cant go straight pipe from the turbo back could i go mufflerless with no problems?

Thansk for all the helps u guys give! you're a great help to us noobs ;) set me straight if i screw something up...
 
#2 ·
I'm pretty sure that a cat in the uppipe is a BAD idea. I don't think any aftermarket ones even have it.... though turboxs might have a high flow one but still, I think most people would agree cat in uppipe = bad. Especially if you want to run a catless downpipe, just go catless the whole way through. Also a lot of online vendors for the wrx have the sensor fixes, one example place would be http://www.gruppe-s.com/index.htm
 
#3 ·
so how does that fix get installed? just splice the ends and connect? and is it gonna effect the sensors at all if i have no cat in the uppipe? will it be detectable when they check my computer that the back has just been looped?

thanks for the help Gonk!
 
#8 ·
nixstur said:
Check out Random Technology on www.xcceleartion.com. They make such an animal. Though, a cat in the uppipe is still just a piss-poor design, and why they have to have 2 cats in the exhaust instead of just one( like most cars ) also boggles my small mind...
You will find many new cars available today have 2 cats. Smaller
pre-cat(s) up close to the engine for quick "light-off" for cold emissions. Most are right after the header (such as in the WRX up-pipe) and the regular main one further down the pipe to handle regular duty. The EPA restrictions have been tightened plus many companies are making LEV, ULEV, S-ULEV for California regulations. If I'm not mistaken the WRX is an LEV.
 
#11 ·
yeah, her new b/f is cool but she can go where i said. she treated me like S*** after 3 1/2 yrs she just left me and was a total B. no real good reason. but then again it is good she's gone cause the money i saved to go live with her went for the subi's down payment, and without her to waste my hard earned cash i can afford it! thanks for ya'lls help!
 
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