I wanna do something to my exhaust, well i was wondering if making a straight pipe afer the 2 cat converters would damper the HP cause ita a 4cyl i heard it could lose HP


thanks

 

do you mean replace the cats with a straight pipe, or ??putting a straight pipe after them?? or do you mean having an open exhaust after the cats with no muffler? i hope you mean replacing the cats with a straight pipe if you did that you would probably experience a small drop in power in the low rpm range and a slightly larger increase in high rpm power you would also experience failing emissions and your CEL would go on. if you replaced one with a sraight pipe you would be better off the first i think(not positive about the integrated part) is integrated into the exhaust manifold with o2 sensors before and after it so removing it would make mr obd II pissy and turn on the CEL unless you fooled it electronically or moved the sensors to before and after the second cat(i am also not sure if the sensor relocation would work, it is just theory, i have not tried it the 2 cats might have different efficiancy levels maybe someone else knows). if you replaced the second cat you should be ok

 

I gutted my first cat but my cel wont go off...now I have to mod the 2nd o2 sensor to "think" that is ok...

 

Damn. Cyrax. Cats suck but so does air pollution. I think.

 

i was gonna do straight after the 2nd cat and do straight pipe to the end of the car, leaving the cats on

 

sounds good to me,it will be loud tho and if it is as loud as i think it will be you will have trouble explaining it to the police officer whois screaming at you to shut off the engine while he frantically clutches his ears with both hands it also probably won't be the tuned sounding loud you get with a nice exhaust. more like running a chainsaw over with a lawnmower, yes that's it. but on the other hand you might be ok because the cats do have a somewhat muffling effect so it wouldn't be as bad as open headers. i say if you want to risk the ticket try taking off your muffler and see i you like it......at least the CEL should stay off, unless the noise shakes something loose

 

well if my GMC pick up with a 350 and straight pipes with no cats doesnt get me pulled over i think i will be ok, out county doesnt have emissions laws.

see in my redneck part of the state, if u have a truck with stock mufflers, u might get pulled over just cause of that. even the cops own loud trucks, its really funny here.

 

then you should be ok. in fact you could probably lop off the second cat withno problem too as long as you don't remove, break, damage, hurt, or otherwise impair your o2 sensors. if you got the electronic o2 sensor simulators you could take off the whole thing and just run headers to a straight pipe. or if you don't care if the cel is on all the time dont spend the money on the sensor foolers, hell after a while the cel might even burn out, and that takes care of that problem. hehe
but seriously you will lose some low rpm power and gain some in the high end. just don't go crazy with pipe diameter and you'll be ok. if you do go the straight pipe route, you should get the o2 sensor simulaters

 

Replace the 2nd cat with RoadRace's test pipe. Wire back in the O2 sensor. Run up to 2.5" piping. Anything bigger and your torque will happily go down the drain. Worry about the first cat later. More than a hassle and it's definitely the picky one of the two.

 

arent you the fella that everyone was joking with about stabbing youre cat with a ice pick and then slamming it around to knock all the debris out? bet you wish you bought a test pip dont ya

Myself I am going to get the RMR headers that have the sensor plugin and the rrm test pipe to replace the second cat. Will this be just like running a straight pipe system,with the exception of the rrm muffler on the rear of course. And w has anyone else that has a header with no built in cat and installed a straight pipe noticed how loud the car is ?