Alex6969

This summer I plan on buying and rebuilding/porting a friend of mine's motor. Its from an 87 gxl automatic. aside from the different vac lines, are there any other differences between the auto and manual motors?

thanks guys

jhammons01

I'm not the person to ask, but I can't see anyreason for there to be a different motor. There is the thrust Bearing in the back of the e-shaft and the Counter weights. The Vacuum lines for the AT. All that is bolt on stuff for the long block. Everything else should be the same

*hides under desk and waits for Kevin Landers' correction*

Icemark

Throttle body accessories and wire stuff are the only differences

Alex6969

now more questions. feel free to rip into me if this has been covered before, I'm at school, and the search funtion takes FOREVER to load.

so i could just swap over my 86's throttle body or an s5 TB (possibly)?
what are the wiring diferences? the only ones i can think of off the top of my head are the switches in the tranny.
would i be able to use my ECU? and throw in low imp injectors and use an SFAC?

thanks again guys, you make owning one of these alot easier

SureShot

And the counter weight & flex plate on the back.

The bad - The automatic has no flywheel.
The good - an aftermarket light weight flywheel will bolt right up to the rear counterweight.

Alex6969

sweetness i planned on getting one anyway!

Icemark

, yes you could use a S5 throttle body, but it has no prevision for a MOP which the S4 models have.

You just couldn't use a S4 non turbo Throttle body on a non turbo S5 intake, unless the body of the throttle body is modified.


Yeah I would have to look (as I normally avoid auto trannys in RX-7s like the plague), but as I recall there is a control valve at the throttle body and the tranny wires are different.

Alex6969

hmmm i've seen a full s5 intake swap done on s4's can't you modify the s5 intake to accept the s4 MOP?

would it be best to use my 86 ECU on the auto motor? to me it seems like the same ****

Icemark

Yes, but you use the S4 throttle body and hack off a corner of it so that it fits on the S5 intake.

Use the ECU based on the motor.

Hench if you are using a 86-88 motor, you would be using a N326 or N327 (based on your injectors).

Alex6969

well since i'm running low imp injectors and i'm getting a new set sometime here that are brand new i'd figure i'd just keep them, and run the same ECU. I'm not certain if the auto motor is pre 87.5 or not. I figure that would save me from having to hack up the resistor pack and/or wiring harness. if i do run the auto ECU are the wiring harnesses the same except for that one sensor you mentioned Icemark?

Icemark

You would only use a automatic tranny computer if you had a automatic tranny. The ECU is the same regardless of what tranny is in the car.

Alex6969

thats the thing, i'm using a manual tranny, whether i rebuild it with miata gears or not is still up in the air