R45

I was wondering what you can and can't do to the exhaust system on an 86-88 n/a if you want the 5th and 6th ports to still work. Can you do any reliable mods to keep them still working? I would like to know what others have done as well and what kind of power loses is the ports don't open?

87RX7NA

I hear you can use the Racing Beat Header/Precilencer setup and the ports will still open. If you want to do something like straight pipes, then you can always wire the ports open. It's pretty easy. You'll notice a very slight drop in low end torque, but all the HP will still be there. You can add any cat-back and the ports will still open. Hope that helps a little.

Baldy

I thought that applies for s4? isn't he asking about s5?

R45

thanks for the advise. And Baldy it is an S4. The S5 were from 89-91

FCmaniac

yeah, as long as you have the backpressure tube hooked up from your main cat or presilencer with at least 2-3 psi, your 5/6 ports should open.



I am against wiring the ports open if you can avoid it since all you are doing is losing low end and gaining nothing at all..... plus one of my S4's right now has no backpressure/split air pipe hooked up and when I wired them open temporarily, the torque loss was just too much for me... not worth it.

RX7 13B 4 UR AZZ

Ok what are they. Are they on the exhaust or on the intake? can someone tell me how to tell if they are working or not.

spiney360

they are for the intake, the run off acuaters(did i spell that right?)the open and close for more air and fuel to get in to the cumbustion chamber

Seppuku

they are located above the exhuast manifold. you can try greasing them and then driving the car and see if the grease moved.

They should open around 5000rpms. if they dont work you would probably notice it becuade the car wouldnt pull as well as it did in the lower rpms. Im sure someone else can give you a better discription if needed.

isamu

Yep, what everybody else said. You can't see the sleeves because they are in the lower intake manifold. But you can see the vacuum actuaters that turn the sleeves. Here is a pic of the actuators. I painted mine blue to let a little bit of the ricer in me out

isamu

Here is another pic that might help. This is with the LIM (lower intake manifold) removed. You can see the end of the sleeve sticking out of the secondary hole on the engine side.