replacing cat with str8 pipe.
 

Ok my buddy has a 98 integra and he says he heard everywhere that if he replaces his stock cat with str8 pipe on his stock car with stock exhaust he will gain 20hp, i pulled a bs card on him but ey i dont know everything, just to prove my point can somebody give me a opinion on that?

you might gain some hp, it would help alot only if, the stock cat is old and super restrictive. But straight pipe is louder.... too loud depending on muffler to go with it, but 20hp.... maybe if you consider one thing, the car is 140 stock, over years of use, and wear and tear, and a dirty clogged cat, you might be at 130, or less, with straight pipe and tune up, you might be back at a 145-150.

Im gonna stop, im just talking out my ass now.

yea like i said some but not near 20hp.

20 hp - Yeah right..

Maybe 5hp if that. tell him to get a high flow cat. If he gets a test pipe he will get a CEL for secondary o2 sensor.

Im made this thread to prove my point and push him in a right direction, after i get couple good answers im gonna show it to him and let him read it.

buy a high flow cat. cleaner crisper sound and same HP gains which is not 20hp maybe 5 if he is lucky but im thinkn more like 2 or 3

only a couple HP will be gained. had one on my teg, nothing special.

20 hp is a lot to gain especially if he is talking na. moreso if he means whp. as stated he will gain some but not 20...

Barely any... you guys toss around these 130 and 140 numbers like its actually getting to the floor, which most likely it isnt.

say 4 hp at the most.. which he wont notice, only a smooth power band. He'll also notice a drop in low end power, and might gain a bit in the top end.. other than that he's just making his car louder, and the exhaust out the muffler dirtier..

If he still wants to do this, he's going to have a CEL, but that can go away with a non-fouler to trick the ECM into reading something decent from the O2 sensor..

or he could just not do it at all..

he can also avoid the CEL by converting to obd1, thats what i did