i know my ports are not opening so i wired them open a while ago and now i just want them to work properly, i have an 87 so i know the backpressure opens them. i havent touched them other than the zipties to open them and i noticed the nipples on the bottom have nothing connected to them, is this where the line should go from the exhaust? or is it behind them out of view, i dont understand why the guy that had it before me would have completely disconnected them? could somebody just tell me how they are connected to the exhaust??
another thing, on an s5 the air pump opens them, what does the airpump do on an s4?

 

bump, any info?

 

Vacuum lines are suppose to go to the those nipples. I'm not entirelly sure how since my car is S5 and yours is S4 so there's a difference.

 

The Air Pump on both S4 and S5 pumps air to the main cat as well if you still have it. If you got no cats then there is no need for the airpump on an S4, so tear it out of there.

 

I'm planning on installing RB headers, high flow cat., and cat-back in a few days on my S4 instead of the RB header-presilencer combo. without the air pump and ACV will it muck up my high flow cat.? or is that only the stock cat. And (since my air pump and ACV are gone) should I do the presilencer instead? I'd rather get the presilencer now than have to do more exhaust work in a month if its going to clog the high flow cat.
Thanks,
-Cyrus

 

I'd go with the presilencer, i hear you get the most HP from it. It's what i'm planning on doing....someday....