DrifterX

i got a straight exhaust from my friend but it didn't have the side pipe that goes to the smog pump so my question is do you guys think my ports are still opening or will i have to have the side pipe welded to the straight exhaust to open them and if i do that will i be making enough back preasure to open them 100%? .

ddub

I'll assume you have an s4 then if you had the split air pipe ("side pipe") that you're talking about. Without that hooked up, no they're not opening. Even if you did hook it up like that I don't think they'd open since it's straight pipe, you need back pressure to open the ports that way. Look into opening them via the airpump or other means by searching.

DrifterX

i have an s5 91 will have to search for that.

ddub

If you have an s5 then your ports were never opened by the backpressure from that pipe. For s5's they used the airpump to actuate the aux ports and the VDI, the split air pipe was just to supply air to the cat. So as long as your airpump and stuff are still there, your ports are opening.

DrifterX

one more question so i guess that split air pipe is there to cool the cat if i reconnect that would it keep the pipe's temps down?

ddub

It's there to supply air to help the catalyst I believe, I never heard anything about it cooling it down, but I don't know.

Don't worry about hooking it up if you don't have a cat, plenty of people don't use the pipe after removing their cat/emissions.

DrifterX

ah coo man thanks a lot for the info i guess i will just leave the smog pump open and just let it pump the air to the side.