Another 1.8 Miata swap question...

I might be looking at a swap this summer for my 90 automatic Miata (need an auto as left leg doesn't work). I'd like to eventually add a Megasquirt but that's far in the future. My question is how will the the stock auto ecu play with the 1.8? I googled the heck out of this and couldn't find anything.

It won't really care. You'll increase the capacity of the engine by about 10%, and you'll also increase the injector size by about 10%. It's all good.

You won't find a lot of info about this because 1.6 autos are rare. 0.5% of production comes to mind. We've actually done this swap, but we never tried to make it work on the stock ECU because we were turbocharging at the same time.

Ok, when it gets done I'll update you to let you know how it went to add to your knowledge.

I'm curious about the turbo option, how did the transmission take the extra power?

mj_wils1970 wrote: I'm curious about the turbo option, how did the transmission take the extra power?

That was my first question also. Never really looked at the autos in these. Where they strong?

Level 10 did some magic to it, we weren't involved. The car had a 2.0 with a fair bit of boost. It was a rocket, actually, as the turbo never came off boost.

Note that this is really only possible with the 1990-93 transmissions, the 1994+ ones are controlled by the ECU and there aren't any aftermarket ones that will do the job.

Mild threadjack: locally there is a 90 smurf blue Miata with an auto-box and matching hardtop. No rust/dents but it's a little rough and has a dead battery at the moment. What would a fair price for such a beast be? It's being auctioned through www.EBTH.com and while I don't need it I do want the top.

Keith Tanner wrote: Note that this is really only possible with the 1990-93 transmissions, the 1994+ ones are controlled by the ECU and there aren't any aftermarket ones that will do the job.

Does this mean the 90 auto does not have any ecu connection at all? From what I read there was a single wire connected to the ecu. It was my basis for believing I needed a parallel ecu / megasquirt to work.

I'd have to check the wiring diagrams - but basically, no. It does not need the ECU.

KyAllroad, fair price on a GRM thread would be $25. In the real world at an auction, I'm going to guess $1500-2000.

Thanks Keith for your input on this!