Reedo

Hello,

First, let me say I am not a car-guy so please forgive any ignorance I may express. I'm posting this on behalf of a friend who isn't good with the Internet and forums and whatnot.

He has a late 80s (87 or 88) turbo with a shot body. He also has a 1990 convertible with a good body and interior. He wants to move the turbo's engine into the convertible.

He is comfortable with all of the mechanics of the move (that's what he does), but he is unsure of the link between the BCM and ECM. He has identified the cable between the two computers on both cars. The wire count is the same but the color code is different. He has been unable to find a wiring diagram in any RX7 books.

The question is whether or not the ECM from the turbo can be dropped into the convertible and wired directly to the BCM in that car.

Does anyone know if this configuration would be supported? Is there any kind of translator computer which needs to sit between the connection? Or do the wires cross directly from one model to the other without regard for the color differences?

Any help or direction would be appreciated.

misterstyx69

iTrader: (142)

86-88 is series 4..S4.
89-91 is series 5..S5.
Yes you can put the series 4 engine into the Series 5 chassis.However since the wiring to the engine/computer and various gauges,etx are different you will have to get the sensors and the wiring and the electrical components for that engine to put to that "other series of car".

You however will most likely get little feedback on this as it has been beaten to death and there are hundreds of threads posted on the subject to substantiate this.
I suggest some coffee and heavy reading in the SEC GEN Specific section and the Archives.

I did the same thing,so don't feel offended.
I actually came out understanding the car better when I started absorbing even the non irrelevant stuff!

Reedo

Thanks for the feedback. I tried to look through the forum for related issues but its a big forum.

Just to be clear, you are saying that he can move the engine but needs to also move all of the electronics (ECM and BCM), wiring, body sensors, and dash gauges. There is no direct way to attach the older engine to the newer body sensors and gauges.

Is that correct?

Also, could I trouble you for a link to the recommended reading material?

misterstyx69

iTrader: (142)

Just to Welcome you in I'll hand you a Bone.!
Rotary Resurrection home of the budget rebuild.
It's not ON the Forum but rather on a Member's site.

Evil Aviator

You are basically looking at two issues:
1. Turbo engine to a non-turbo car
2. S4 engine to a S5 car.
I would focus mostly on the first issue in this case, and I would recommend moving the entire turbo drivetrain (engine, transmission, driveshaft, differential, and rear subframe) into the convertible. The rear subframe is easy to swap from one car to the other, and you can even leave the bottom of the shock absorbers attached, so keep this in mind before you waste your time disassembling everything.

See the NON-Turbo to TURBO Conversion link at this site:
Rotary Resurrection home of the budget rebuild.

See the below site for factory service manuals and wiring diagrams. The wiring harness diagrams that will probably be the most helpful are the last of the wiring diagrams.
Foxed.ca - Mazda RX-7 Manuals

Edit: Dangit, misterstyx69 beat me to it, lol.

Rikk

iTrader: (2)

Search for the thread title "From N/A to Turbo:My New Turbo II"
GL

Reedo

Thanks everyone. I really appreciate the link; it's not that I'm in capable or unwilling to perform the search myself, but that I'm not qualified to gauge the accuracy or value of the information I find. It seems that, regardless of the subject matter, for every one good post on the net there are ten more that are not so good. So I really to appreciate being pointed in the right direction.

I think that he does plan to move the whole drive train and rear end. Its the wiring to the dash and lights and sensors and whatnot that is the concern. From looking at that link, and what I understand, it seems like perhaps he can get away with swapping some wires and running his own turbo guage.

I'll get this info over to him and see if it is enough to resolve his issue.

Thanks again.

Aaron Cake

iTrader: (1)

Do you intend to modify this engine at all once installed? If so, you can save yourself a LOT of wiring hassle and modification of the stock wiring by just starting with a standalone when the engine is swapped. Plus the result is a new harness, new connectors, and a clean well understood installation.