Mark S

iTrader: (1)

If your putting the s5 motor into an s4 you'd be using the s5 ecu, correct? Just make sure you swap the air pump and acv stuff and you'll be fine. You will also need to plug the 2nd hose off the S-4 split air pipe (the small one) cause the S5 system won't use it

Another way would to be by the header from RB. On the RB single systems (For S-4s), the ports are actuated by the pickup tube in the presilencer. The tube goes into the silencer and makes a 90 degree turn so it faces into the exhaust stream. It is the EXHAUST FLOW and not backpressure that actuates the 6p. (This is why the ports still work fine with aftermarket cat-back systems which are lower backpressure) If you just stick a tube into the pipe it won't do dick. The location and diameter of the pick-up pipe are very important for the timing of the actuators. The exhaust then runs back up the split air pipe to the operate actuators (on an S-4). It's easiest to just buy the part from RB and be done with it (ask me how I know)

RB also makes a HEADER designed to actuate the ports on S-4s and s5s without a presilencer. In this set-up, a small pickup tube is placed on the front rotor header tube. The port for the tube is located in a position so the exhaust has a straight shot to it as it exits the engine. You either just plug the outlet hose onto the actuators (S-4) or to the hose on the ACV (S-5) (The pick-up tube provides the positive pressure necessary to actuate the 6p and the VDI) This is the setup I have on my S-5(with true dual exhaust) and it allows me to ditch the air-pump.

There are also write-ups on how to use electric servos in place of the dashpots to work the actuators. If you search this site, there's plenty of info on it.

SoloIIdrift

So it would rely on backpressure?

The entire motor is a 1990, so I'm assuming it's the PUSH UP style.

I'm confused, so on the motor, I could use an rpm switch to open the ACV or vac line that would open the 6 ports and VDI?

SoloIIdrift

Nope, I'll be using the S4 ECU/stuff, swapping the injectors and TPS from the S4 car onto the S5 motor.

Oh what a headache I have now, so basically I should use an RPM switch to activate the 6ports and VDI right?

banzaitoyota

What are you using to control the Electric OMP on the S5??

SoloIIdrift

Thats another thing I'm swapping the mechanical OMP from the '87 onto the '90 motor.

Mark S

iTrader: (1)

The Nelson supercharger miriah used to sell puts the blower right there.

Its a paxton SN2000.

Mark S

iTrader: (1)

Well, RPM switch for the VDI anyway. You could use the lower manifold off the S-4, that way you could use the stock S4 actuator system. It's not supposed to be as good as the S-5 (I think the S5 ecu takes into account load, temprature etc when opening the VDI and 6P)

I think the bracket is different for the TPS as well. Not a big deal, but one more thing to worry about.

You sure you just don't want to get an ECU and harness from a JY? (Also try www.mazdasurplus.com if you want new parts) The ECU is supposed to be twice as fast as the S-4 as well.

redstreak

Ok I don't have the time to read all the posts so sorry If this was already mentioned.

they begin to open at 1.5 PSI and are fully open at 3 PSI which is between 3500 and 4500 (I think).

NZConvertible

You should have, I posted the correct figures above.

Series 4:
Starts to open at 1.2psi
Fully open at 2.1psi

Series 5:
Starts to open at 0.85psi
Fully open at 1.4psi