i have an 87 non-turbo with an aftermarket exhaust and no air pump. i am clueless on how to open up my 5th and 6th ports. i have heard that there is not enough exhaust back pressure to open them up with an aftermarket exhaust. i know there are ways to do it, i just don't know what they are and how to do them. i would appreciate any help.

 

The S4's (86-88 rx7's) opened the 5th and 6th ports WITH the exhaust. I'm not sure what the procedure is for fixing them on an S4 with a aftermarket exhaust, but if you want you can open them permanently. This will hurt your low end a little but will give you back all your top end.

 

You have a full RB exhaust on there yeah?


If so you should have a backpressure tube comming off one of you pre-silencers and going to the 5&6 port actuators. Check to see that all of this is in place.

If it is, and they are still not opening at 3800(ish) RPM, take them apart and clean them up as they might be stuck. Or you could ditch them all togeather. I don't have them on my SE and it pulls hard down low and up high..............


Good luck,

--Alex