hey i got rb headers for a 91 na. my question is if i buy a rb presilencer, does the air pump attatch to it? or what do you do with the air pump? i dont wanna buy it and not be able to use it ya know. please let me know.

 

the split air return pipe attaches to it just like it does on your cat(witch yes goes to the air pump).

 

i have a 90 n/a and i just took my air pump off and put a block off plate on the little presilencer inlet...But if you need emissions testing keep your air pump on...but if you have a hookup or live in a no emissions area just block it off...

 

Oops.

 

The air pump is independent of the exhaust system and should not be removed on and S5 N/A, because it is what operates your aux ports.

The ACV (air control valve) has a pipe that feeds air to the cat converter for emissions purposes.

When you get a presilencer and ditch the cat the split air pipe from the ACV is useless and you can just cap the little nipple on the ACV.

But the airpump (which feeds the ACV) and the ACV itself are needed on an S5 N/A unless you have engineered some other way to activate your 5th and 6th ports (or locked them open (which hurts low end torque).

 

Your car is way down on top end power without that air pump (unless you locked your aux ports open) in which case the car is down on low end torque)

 

the air pump just pumps air into the exhaust to lower emissions....the aux ports are operated by vaccum.

 

removing the air pump will not make you lose any power like i said in the post above all the air pump does it pump air into the cat to lower emissions....youll gain power if anything, from the parasitic loss

 

Ummm... no....

On S5's the auxilliary ports are operated by the air pump.

On S4's they're operated by exhaust velocity.

If he takes off his air pump, he'll lose the operation of his auxilliary ports. Thus... losing top end power.