jjandros

iTrader: (7)

Went ahead and picked up a REV II exhaust for 200 from a local and am thinking about hooking it up on my S4 n/a to replace the stock setup. Seeing as the S4 uses back pressure to open the secondary ports what's my best option for a header? Or should I use the stock exhaust manifold with a 2" - 3" adapter? I figure a header will add better flow but I'm not sure as to how to keep the backpressure tube. Any ideas or experience appreciated.

86rxNa

racing beat sells the header with a pick up tube on it. I went with the true dual exhaust for mine.

Derekcat

iTrader: (8)

Eliminate the exhaust pressure method... Convert to airpump pressure. Much more reliable.

jjandros

iTrader: (7)

link? or search term? I tried searching and came up with a lot of threads just talking about wanting to do it instead of explaining.

jjwalker

You use a vac/pressure solenoid and a RPM activated switch

Derekcat

iTrader: (8)

https://www.rx7club.com/2nd-generati...itches-907824/

You can ignore the VDI part unless you want to swap to an S5 intake.

Otherwise, search for posts with my username and you should be able to find a picture of the ghetto/analog method.. Basically:
Air pump pressure to a T, one end steps down and goes to the 5th/6th nipple, the other has a valve on it that dumps to air [or ideally the ACV's silencer].. Just adjust the valve so that when you hit ~36-3800RPMs the ports are fully open.