So I seem to be in a little of trouble I think. I have a 91 GTU that I pulled the engine out of and had a friend rebuild with the rotary aviations kit. The engine is back together and in the car, but now I'm having trouble with figuring how the actuators even work. Most of the info I read says the s4 actuators open via an exhaust hose. And the s5 vdi opens from the vacuum rat nest.

Well in my case the car never had high rpm power to begin with (always had as much power at 2k rpm as 6k rpm). When I pulled the engine out, I noticed that vacuum rat nest was more or less shattered in pieces, and upon touching them they broke more. So all that is in the garbage, and now I have no idea how to hook up the actuators or vdi. Oh and I'm not sure I have the air pump anymore either. Everyone with turbo II's all say just to trash all that stuff anyway.

So if anyone has any advice on how to hook up or rig the actuators and vdi, I would greatly appreciate it. Also IF I have to take out the sleeves, can I do that with the engine still together.

 

Get a service manual and hook it all up properly, or people on here have actuated that stuff off of rpm based switches.

Do not trash that system. Its the rotary equivalent to VTEC, so it makes no sense to get rid of it. Fix it right.

 

The 6pi sleeves can be removed with the engine together yes. The s5 setup works by directing air from the air pump to two solenoids that are ECU controlled. When the ecu activates them air from the pump and directed at two actuators that push out to roll open the sleeves in the uim(vdi) and irons(6pi). If the rats nest was in that bad of condition thye probably never worked. You should at least try them out before removing it.

 

Wow thank you SpikeDerailed, that was a perfect explanation of the system.

I will look into the manual and try and hook them up the original way, now that I understand the system of the s5. If I end up missing too many important components, I'll look into those rpm switches.

Thank you guys for your help.

 

RPM switches would just complicate things. The ECU controls the 6PI and VDI solenoids on the rack, so if you really had to you could just route air from the air pump to them directly. But I'd just go through and replace all of the vacuum hose. It's not that difficult, and should be one of the first things you do anyhow.

This page is primarily for S4 NAs, but there is a diagram from the S5 FSM part way down that shows the 6PI setup: http://mazdarx7.iougs.com/intakeair.shtml.