Hi everyone. I'm currently building my first RX7 and have run into some snags.



The car is a 1990 GXL and I am in the middle of swapping what I thought was a JDM S5 Turbo II engine into the car. While rebuilding the engine I discovered that it is actually an S4 turbo II engine. It also came with a tranny still attached.



Here is what I have:

S4 Turbo II engine complete with JDM RHD harness with ECU. It came with the TB and everything. It's all there save for the intake hose and MAF.



In prep for the swap I have purchased:

1. S5 USDM TII engine harness

2. S5 Turbo II MAF meter

3. Turbo II pressure sensor (passenger side strut tower)

4. Mazdatrix hybrid drive shaft for turbo tranny to NA rear end.

5. New hoses and block off plates for emissions removal.

6. Other small misc things like a FMIC, etc......



Here's my question:

I know that to swap an S5 motor into an S4 the S4 harness will not plug into the S5 guage cluster harness. I assume that the same is true when going to S4 from S5.



What parts do I need to swap in order to use my S5 Harness with my newly rebuilt S4 engine?



Obviously I'll need an S5 ECU now. What about the Throttle body and will I need to swap the solenoids in the rat's nest?



Please guys I've searched all over and can't quite get a clear answer. Any help will be very much appreciated.