I'm engine swapping a 1991 RX7 rotary into my 1975 MG Midget. I was wondering if there are any ECU's out there that control only the engine. I have the stock ECU and Leading and Trailing ignition coils, but I don't know how the stock ECU would work in anything but a 1991 RX7. If anybody could help me out, I would greatly appreciate it.

Thanks in advance!!
-LazerSquid

 

look into a RTEK 2.1 from digital tuning, inc. They can run stock setup but the tune-ability of a standalone.(tune with a Palm Pilot)

 

You could make the stock computer work with the stock AFM if you want to spend a lot of time, and the Rtek piggyback wouldn't really help much in your case, so I think it would be a lot easier to just use a standalone EMS. The common low-budget standalone EMS products are the Haltech Platinum Sprint RE and Microtech LT-10.
Platinum Sprint RE ECU
LT-10C

Both brands have higher-end products if those models are too basic for your application. There are also other more expensive brands like Motec, AEM, Wolf, and Electromotive, which will work with a rotary engine. I recommend that you choose one that has local support. These things are pretty complicated, and you don't want to need to rely on a phone call to Australia or opinions of the internet forum peanut gallery when you need help. It also helps to talk things over with a professional tuner so that you don't buy something that will not meet your goals, or requre a lot of additional parts that you did not plan on.

You can browse through our EMS section here:
Engine Management Forum - RX7Club.com