has anyone used the o2 sensor hole for using back pressure to operate the 5th and 6th ports. i am currently running a freeflowing exhaust, and i want to remove the airpump. has anyone done this or is it too hot, or will the exhaust from the hole just pump into the the ports? thanks

i really dont want to do that eletric air pump conversion i ve seen. thanks a lot

 

RacingBeat used to run a small line right off the most fwd exhaust port to feed the aux ports. Visit their site to see if they still do that.

It was a long small dia tube, whtich meant it was cooled down on it's end where a hose was connected. See their site.

http://www.racingbeat.com/FRmazda2.htm

Go to HI PERF EXHAUST SYSTEMS and click around. It's there.

 

While it works fine for a stock car, it's a terrible method for a modified car where reducing backpressure is the goal. There's no way to make them open at the correct point in the rev range. They'll open later than they should, mean a loss of potential mid-range performance. I s'pose it's better than wiring them open though...

 

alright thanks. i dont know what im gonna do but i need to do something. is there any other ways you guys do it.

 

Yeap, S4 ports are a pain. After I read about using restrictor plates in the exhaust flanges to eliminate boost creep on turbo cars, I've thought about using restrictors to increase backpressure to operate the 5/6 ports. Tuning them would be a pain, though.

 

Increasing backpressure reduces power. Deliberately restricting your exhaust just to make the aux ports open is proof the system needs to be chucked...

 

The electric 6PI actuation is your best bet. This is because (1) you're getting rid of your air pump anyway, and (2), your car is an '88 and never used the air pump for 6PI, so you wouldn't have the ECU or solenoid to trigger the ports to open.