'86 base model.

Just bought this exhaust:

https://www.rx7club.com/showthread.php?t=660976

RB roadrace header....with no backpressure tube.

If I get a tube welded onto the stock one, and hook it up similiar to this:



do you suppose the ports will still open and close?

I do not especially feel like ghetto rigging a bicycle pump and window switch to open these ports...and I'd like to retain the stock operation as this is currently my DD and wiring the ports open results in quite the hurt to gas mileage.

Otherwise, I plan to eventually pull all the emissions off, is there someway to use the air pump? I suppose I would still need a window switch.

 

http://www.rotaryresurrection.com/2n...elec6port.html

-=Russ=-

 

Thanks, but I'm aware of that method and looking for another route.

 

when I put that exact header on (the one with the air pipe) with the true dual setup my ports opened just fine at about 3500-3800 hell I could be under the hood rev the car and watch them open...

Racing beat did it right and it will open your ports

 

If you wanted to use a header other than the RB one, and wanted to weld a tube on it, you may need to experiment with placement of the tube as well as the size of the restriction (see the narrower end of the tube in the pic???) in order to get the correct opening pressures for the rpm band that you want them open within. The actuators are supposed to start opening at 1.3 psi and are fully open at 2.1 psi, a rather narrow range to play with.

 

That's what I was afraid of.

Something else I was thinking about...should I do it like stock, and run it back to the collector/presilencer thingy, or run it right off the header? 90* to the pipe, or at an angle? I wonder about the diameter, too.

I wouldn't mind getting more than 2PSI...as long as they stay closed beneath 3kRPMS so I can salvage some gas mileage. If my actuators burn out, or whatever, it's no biggie.

 

I haven't had a chance to take an actuator apart yet to see what the diaphragm material consists of. I would assume it would be a silicone or perhaps Viton, so I'm not sure what kind of heat they will take over time. I picture in my mind stronger exhaust pulses with a tube coming right off one header tube, would this lead to erratic operation vs. a tube coming from a downpipe? Would there be increased temps from having such a short tube coming off a header? Some pressure and temp measurements at different locations would be helpful, but time-consuming. I would think Racing Beat has done some R&D on this before releasing their header. Only the Shadow knows. I would also tend to think that pressure readings much above 2 psi would be unwanted, similar to having clogged cats.

 

Here's another idea.

What would it take to convert my S4 6PI to the S5 activation, using the air pump?

I'm pulling the cats and ACV, will leave the air pump if it can be rigged to open the aux ports.

 

The s5 aux ports and VDI use the air pump's pressure to open them via solenoids that are switched at various engine speeds/ loads. It could be done, and I bet others have tried it, I'm not sure how one would trigger a solenoid without a standalone and corresponding trigger mapping capability.

 

I used the airpump on my s4 to open them. I took them off, cleaned them, and used new gaskets. Between my new cat and using the airpump I couldn't tell a difference. so this allowed me to ditch the cat which made me lose low end torque.

look at your air control valve. there is an exhaust tube. right before it bends 90 degrees and leads toward the front of the car to its air muffler. drill a hole in this spot. now you can use a barb or just superglue a vacuum hose in it. now run that hose to your actuator input.

 

Uhm, wouldn't that just hold the ports open all the time?


I just had an idea though. I should do ^^that, but run it to a solenoid or valve wired to a switch on the dashboard or under the throttle.

Ports closed all the time for low end, MPG city driving.

Open all the time when it's time to rock. (although N/A rocking is like a ballet at the amputee ward)


Thoughts? Any ideas on a valve/solenoid that I can wire up with a relay to work? Or is that the way the S5's did?

 

the airpump is operated by the fan belt. the more rpm the more air it spits out. i think it maxes out around 3500 rpm so you wont overload your actuators.

 

Any of the tricks you guys mentioned can be tested easily by placing a vacuum "t" fitting on the hose to your actuators. Use a long section of hose on the "t" and attach a vacuum/ pressure gauge to that hose (inexpensive gauges can be found at auto parts stores I think) and tuck the gauge underneath your driver's side wiper blade so you can see what kind of pressure is going to the actuators. The air pump will surprise you as to how much it puts out at idle.

 

Sounds good, I'll get some PSI readings...I have a feeling it will probably open the ports at idle as well.