Hello fellow enthusiasts, I just wanted to ask a question about "air pump" and "acv". Is it mandatory for me to remove my air pump and block off my acv if I am installing a magnaflow pre-cat and my RB pre-silencer? I chose this set-up because the stench of my fumes are making me nauseous. BTW my car is an '88 S4 NA.

 

Removal is not necessary. The presilencer should have a connection for the air pipe. The problem will be that I'm not sure how much a precat will really clean up your exhaust when used as the only converter.

 

the air pump and ACV actually do a bunch to clean up the exhaust. we smogged a T2 with out cats and it is like 1900ppm of HC's at idle and no cats without the airpump is like 2500ppm of HCs....

i will grant you that 1900hc's is still a lot....

 

@ Jerry thanks for the info, my goal is to minimize the stench, I hope that a pre-cat will help a little bit.
@j9fd3s thanks for sharing, your help is greatly appreciated.

 

By leaving them on, he may get a decently clean exhaust then even with just a precat. I did forget about how much just the extra air will allow for more burning off of hydrocarbons.

 

sounds and smell good to me.