cmac27

Ok so i have been researching and looking into cutting my exhaust a couple feet behind the cat but before the muffler and yes i know what it will sounds like, thats not my question. The question is are there any problems with any sensors or o2 sensors or anything like that and i am also aware of the lack of pressure issues and dont find anything too bad about it for my uses. I was also looking into adding a curved piece of piping on just to shoot the exhaust away to avoid any problems with it coming up into the cabin, and was wondering what metal materials are the best if it matters? thanks and i know the answers are here somewhere but i have searched a little bit.
thanks in advance
-Connor

turner01

I dont think you will have a problom. This weekend I took out my muffler, and just replaced it with 2" pipe and connected it back to the tail pipe. It accualy sounds good, not loud at all nice mellow tone. But that is with the tail pipe still attached. so in your case it might be kinda loud, like you said above. I have not thrown any codes yet. (knock on wood)

okie81

You could try Pep-Boys, Kragen, etc...some of them sell small mandrel bent sections of exhaust pipe you could kick out to the side

turner01

I know it does not measure pressure, but if you have less presure or exhust at the sensor wouldent it give it some sort of diffrent reading. (if that made any sence).

cmac27

i get what your saying. i don't believe pressure would mess with the o2 sensors anyway. (I would imagine sensors would measure amount of whatever they measure in a selected amount of gas) i don't exactly know what components there are to the whole exhaust system cause i havent really looked into this before. I havent read anything about people fabbing sensors unless they go closer to the engine with the mods

JeEVeS

an exhaust system has a back pressure to the exhaust valve where (in short) it has waves that pull air through the motor. (enter EQUAL length headers). i would imagine if you had a few feet of pipe after the header (2-4 ft?) this would not be an issue. I guess where i am getting with this is that after that it dosen't matter what the pipe looks like(ex. straight pipe, 40 series restrictive loud muffler, 80 series free flow quiet muffler, or an old school rat rod exhaust dump out the side.

Imho this should not effect an 02 sensor because it is far enough up in the system. (minor thought, a 3rvz motor has 2 o2 sensors, one that sits further back causing possible problem with my first idea).

Also make sure that you dump the exhaust to somewhere that airflow will take it away, i can imagine a problem with cutting it off right under your drivers seat and the fumes coming straight up.

(another minor thought, anyone pipe there 4runner exhaust out the back instead of the side? can you smell exhaust when rollin down the road with the rear window open?