i heard if u take the air pump off the ports wont open, i also heard they open from back pressure from something in the exhaust.

 

Depends on the year.

S4 uses a combination of back pressure and the airpump to move the acuators, the S5 uses just the airpump.

 

S4 cars use the exhaust backpressure. It will still function fine without the air pump, and units such as the Racing Beat presilencer have the correct pickup to make the ports function without cats or an air pump.

S5 cars use pressure from the air pump, routed through various solenoids, to actuate the aux ports & the VDI. If you remove the air pump on the S5s, you're eliminating basically all your high end power.

-=Russ=-

 

Your 86 uses exhaust backpressure to operate the 6PI system, not air pump pressure.

 

If you remove the air pump on the S5s, you're eliminating basically all your high end power.

-=Russ=-[/QUOTE]

FAQ says that's only on n/a s5's

so what controls aux ports on s5 t2's? or do they have them. FAQ doesn't say anything about t2 ports.

 

Turbo = 4-port (two primary, two secondary)

NA = 6-port (two primary, two secondary, two auxiliary)

 

To clarify NZConvertible's post, the TIIs (both S4 & S5) lack the aux ports and VDI (on S5s). With a turbo cramming air down the intake manifold, there's no need for tuning the manifold lengths.

-=Russ=-

 

thanks

 

my car is an 87 what opens the ports on it the exhaust pressure i hope. and when i get a dynomax or rb cat back with high flow cat will the the exhaust pressure have enought to open them still and do i also have to have the acv hooked up to.

 

If you still have a cat.. you should have enough pressure to open them.. And. you'll want to keep the air pump and the ACV or the cat will probably clog up real quick!!

If not... there are several "ingenious" ways to do it with electric air pumps and RPM switches and stuff like that!!!!