ok so i have an 89 GTU
and i bought an aftermarket exhaust.. i was told that the 88 and below use back pressure to open the ports and taht since i have an 89 i should be good...

but i have the tube thing on my exhaust that leads in the cat and back to the motor...

already put my exhaust on but now that tube is just dangling under my car...

 

The ports for the S5 (89-91) use pressure from the air pump to control them. You can just plug the hole in the aftermarket exhaust.

-b

 

so pretty much its thair for no reason?

 

if tou are talking about the pick-up tube that on the exhaust, its there cuz you either bought an exhaust for an s4 or its there so that the exhaust will work on both s4s and s5s (more economical to produce one unit vs two diff units). as said before, block it off with a plate or weld it shut.

 

the tube is the one that comes out of the motor and is saposed to go in my stock cat...

 

so you have a cat? then you need to hook the tube up to your air pump. check the FSM for details.

 

ok, that line is from the air pump to the cat. if you have no cat (aka a presilencer or a testpipe or whatever you wanna call it) then you have no need for that pipe and no need for the air pump (its sole purpose is to support the cat) toss em both. for that matter, almost all your emmissions equip. is designed to support/work with the cat. if you have no cat, you can ditch them all. if you still have a cat, you need to hook that pipe back up (unless the cat is gutted of course)

 

i have a test pipe... and i havent traced the line back to the motor... but when my exhaust was stock the pipe went into the car from the motor area...

 

that pipe goes to the air pump. like i said, w/o a cat, your airpump is useless, just toss it. if you have no smog where you (i hope you dont cause you will NOT pass without a cat) are then delete the rest of your emmisions (EGR, ACV, etc) since there pretty useless now too.

 

thanks alot...!

still dont really get what the point of an air pump just going out my exhaust is tho lol

 

it provides fresh air to the cat. since you dont have the cat, no need for the pump haha

 

alrighty then..
ill probably just clamp the pipe off...

thanks alot!

 

if you insist on keeping the pump (dunno why) just remove the line and let the pump blow right out. i dunno what would happen if you clamp it since air is constantly being blown out

 

If you don't have emmissions in your state the ditch the pump and the line. If you do have it, you will have to hook it up to your cat.