Taking the cat out

[ILikeMy240sx]

I have a 96 240sx... OBDII

If I take the cat out and replace it with a testpipe I know it will trigger the check engine light... Is there anyway to prevent the ECU from triggering the light?

[4felix20]

are you sure? i thought the last o2 was before the cat..?

[ILikeMy240sx]

This is from the FSM... Are they talking about the pre-cat?

[Spec-R]

will taking the cat out be beneficial to performance?? i have a 3' exhaust. and you hear alot that you will loose some of the low-end power, but gain top end? does anyone have any experience with this??

[SeVa-S13]

You have a 3" exhauts on your NA KA and a welded diff?

[hybrid_flyer]

no there really isnt, unless you can figure out a creative way to fool the O2 sensor to into switching above and below .45 volts 60 times a second.

The results could net some gains, but with a 3" exhaust you are actually taking away power from a NA engine. Now you dont have sufficient backpressure on your system. But hey whatever floats your boat.

[Spec-R]

the 3'inch exhuast is a pre turbo thing. mine has a resonator, im not sure if its for sound purposes or for backpressure. and yes i have a welded diff. i got a good deal on it, so its well worth it. almost the same thing as a clutch lsd.

[nismofly]

thats the same thing im going to do, get a 80mm exhaust first with my na ka then when i get a turbo i wont have to change my exhaust

[SeVa-S13]

Don't think a welded diff is anywhere near a proper LSD. No offense but while it may be kinda nice in a straight line, it will eventually break and that is VERY hazardous for your health and anyone around you. So when ya get some money, you may wanna look into a real differential because beisdes the wheel hop in turns and stuff, the whole unreliability factor is somewhat troubling.

[Spec-R]

yea i know what you mean. but mine is by a guy named luke. from Zilvia, who has done a bunch of them, and used it on his full drift car. its welded in 4 places. id love to get a 2 way, but i dont have 800 bucks to spend, especially on a lsd, so the welded will have to do. lemme tell you though, getting sideways is some much easier and fun, then with an open diff.

[Spec-R]

back on the whole exhaust question, does the resonator have any influence on backpressure??? or is it to soften the sound???

[gabossie]

Resonator is for sound, and unless you are running a track car, don't take the cat out. I know I sound like a hippie, but they do good things for the environment, and removing it will yield VERY mild gains on a stock engine. When you go turbo, look into a high flow cat. You have to breath that **** just the same as the rest of us do.

[SeVa-S13]

Resonator is for sound, and unless you are running a track car, don't take the cat out. I know I sound like a hippie, but they do good things for the environment, and removing it will yield VERY mild gains on a stock engine. When you go turbo, look into a high flow cat. You have to breath that **** just the same as the rest of us do.

Bingo. Stock Nissan cats tradistionally flow well so unless it's clogged, leave it alone, or replace it with a quality high flow one. Test pipes yield very minimal gains and just make your car sound worse.

[Assmunke]

i have a 2.5 inch exhuast with a magnaflow resonator and muffler. it sounds good, a nice growl but it is loud. you really notice it on the freeway my top end is noticably better, and i dont notice a loss on the bottom end. now i just need a turbo.