i have an 86 n/a i was planning on running an aftermarket header, exhaust, with no cats. will i still need the air pump if i do all that? (i dont have to worry about emissions)

 

no but if u change the exhaust your 5th and 6th ports wont work and u will ahve to hook up a eletric pump

 

i thought air pump main function was to pump air for the cat...cat needs air or else it will cook itself in not time.

 

On S5s the air pump is used to activate the 5th and 6th ports. On S4s its only to help emissions, since the aux ports are activated by the backpressure from the exhaust.

 

so what if you dont have enough backpressure?
how would you know if they are opening...?

 

start your car pop the hood....press on the throttle cable and if it doesnt come down after about 4k rpm then its not working, and would need air pump or electronic activation for it to work

 

not true. the 5th and 6th ports work off of bck pressure while under load not just free revving. there are tones of threads about the 5th and 6th port and how it works. just use the search button

 

Disregard post #6. For the aux ports to be activated by the back pressure from the exhaust you need to make sure that metal tube (?) coming from the back of the engine that bolted on to the stock cat, is connected to where the cat would be in an aftermarket exhaust.

To test the 5th and 6th ports (which only operate under load) apply grease on them and check after a spirited drive to see if the grease has moved at all.

 

i have a s5 turbo 2 swap in my 90 convertibla and i took the air pump off. should i worry...im fixin to have 3" exhaust welded to the cat and then 3" from thr cat to a tip. am i gna need the air pump...all ihave is the 1 belt 4 the alternator...i never heard anythinf bout the 5 n 6 ports not opening up if u dnt have an air pump....thats kinda gay.

 

Only the naturally aspirated engines have the 5th and 6th ports, I would assume that the air pumps on TIIs are just for emissions but am not sure.

 

No you do not need the airpump, you will however need to block off the ACV.

 

I dont have the split air pipe connected to anywhere...
when i got my car the pipe was sawed in half...
my exhaust has a lot of backpressure though...
and i have a streetport..
does this matter?

 

ok cool. The ACV valve is wut the pipe coming off the air pump into the motor is....so just get a plate to block off that valve. ite cool preciate it. ill post pics of my complete swap soon.