6G Celicas Forums

does any body know if i will get any hp form cutting off my can converter ? or will it just hirt my car more then it would help .

Well if your talking abotu the CAT...I have heard diferent stories. I mean casue you dont want to push alot o air in and have it where it cant get out and on the other hand you dont want to push some in and have too much flow coming out. So who knows.
I have mine done and I seen soem performeance but jsut gut it and stick it back up there its and easy and free mod!

This does add hp but you will need a freer flowing exhaust other than stock or you will create back pressure... also it's illegal... which makes no diff to me cuz the cops around here all know me by name... kinda sucks where there 1/4million people that live here.... back to the cat... the best thing that you can do if your worried about it being legal is to remove the cat temporaily, get some straight piping that is just a hair smaller than the stock pipe leading into the cat and insert it into the cat. inside your cat is this honeycomb stuff.... hammer that new pipe threw the honeycomb stuff and then remove the pipe. clean it out and put it back into your cat. trim the edges and hook it back up to your car... you will bypass the cat this way and still look legal to any nosey cops...

I have had a full custom system made for mine including cat replacement, don't worry about the cops its not like they go round testing emissions. What is a good thing to do though is cut the flanges off the pipe connecting to the cat and weld them onto your new exhaust so if you do need to put the cat back on for any reason it is a simple case of just sliding the replacement pipe out and bolting the cat back in as all the fittings are already there.
I noticed power gains nothing major but it also gives you a really good engine note.

QUOTE (NEVERSTOP @ Nov 30 2002, 11:55 PM)

This does add hp but you will need a freer flowing exhaust other than stock or you will create back pressure... also it's illegal... which makes no diff to me cuz the cops around here all know me by name... kinda sucks where there 1/4million people that live here.... back to the cat... the best thing that you can do if your worried about it being legal is to remove the cat temporaily, get some straight piping that is just a hair smaller than the stock pipe leading into the cat and insert it into the cat. inside your cat is this honeycomb stuff.... hammer that new pipe threw the honeycomb stuff and then remove the pipe. clean it out and put it back into your cat. trim the edges and hook it back up to your car... you will bypass the cat this way and still look legal to any nosey cops...

unless he has to pass emissions in his county...
that's one thing to check man, it may make a check engine light come on, and it's gonna screw w/ the emissions of the car, and you might have to turn around and buy a new cat after you do that. if you wanna do somethin similar to what NEVERSTOP was sayin, make a test pipe. basically, you measure from flange to flange on the CAT, then make a pipe that long, and put a matching flange on each side. that way, you can interchange the 2 by unbolting/bolting on whichever you need on emissions day, and you don't ruin a perfectly good catalytic converter. also, that's gonna make the exhaust a little louder, so w/ a larger after-cat exhaust, you'll wanna think about makin sure you keep a resonator on there, or else it'll rasp out the mufler and sound like a big ol assbag.
-John-

When I removed my cat I had no probs with o2 sensors or check engine lights... but mine is a 94 and that was kinda before the whole emmissions thing. I guess it would depend on what year your celica is. But I do like the idea myneyes had about interchangeable pieces... that would be nice a your local dragstrip....

i dont think it makes much of a diference. the reason there are so many mixed opinions on this subject is because most people that do it have it done the same time that they do there whole exhaust. thats why they think that it helped the horspower. the only difference you will get in taking out or replaceing it is if the old one was start to get clogged or something. and it will have an effect on the exhaust tone( good or bad i dont know).


Well if your talking abotu the CAT...I have heard diferent stories. I mean casue you dont want to push alot o air in and have it where it cant get out and on the other hand you dont want to push some in and have too much flow coming out. So who knows.
I have mine done and I seen soem performeance but jsut gut it and stick it back up there its and easy and free mod!


its not like you are pushing air from a smaller pipe into a larger pipe and then back into a smaller one because the reason the cat is bigger than the rest of the exhaust piping is because of the honeycomb stuff inside it. the honeycomb stuff inside takes up space, so in order to compensate they make the canester larger. now if you gut it out then you would have a section of pipe with a larger volume than the rest but it will not restrict anything. the air will just move slower when it reaches that portion and then go faster when it hits the smaller part again. so it really doesnt make much of a difference. i got one for my old eclipse and the only difference between the factory one and the highflow one was wieght. the performance one was i little lighter. i hardly think its worth trouble.