Size of megasquirt vs OEM ECU?
 

I'm looking to run STS2 next year and I'd like to megasquirt my 94 to get some extra power out of it, but there is one hitch. The megasquirt ECU must fit into the OEM ECU case and use the stock inputs and outputs(stock injectors, stock O2 sensor, stock CAS etc). Does anyone know if this is possible? I've read through the DIYautotune article so it seems that using the stock sensors/injectors/spark is straightforward if not plug and play, but what about the size of the megasquirt board vs. the OEM ECU case?

the MS looks a lot smaller. I'm sure it could be adapted

i have both sitting on my desk right now... i think the MS board would fit in the stock ecu case, but you would for sure have to use the stock ecu connector in the MS, and that will thake some tricky soldering. But just from first glance, it does look possible..

The Megasquirt board is a 4" x 6" board. I haven't measured it to see if it fits inside a stock case, and I haven't seen anyone tune it to use the stock AFM. But I know the latter should be possible. And I know for a fact that all the other sensors can be made to work with Megasquirt.

I believe the PCB board will fit but I am not sure about the height of megasquirt. I will be able to let you know later today. I plan on starting my install in my 94 and should be able to tell you how it goes.

I know a lot of guys in STS2 haven't been able to make it fit for some reason or another...it'd be nice for a lot of them if they were able to do it

I really thing it comes down to being to tall. With MOV1 and the map sensor it jsut seems like it wont fit. I will be able to give a good response in a couple of hours when I put them next to each other and see.

i dont think height is an issue... might have to adjust some components... but what about the vaccum line for the MAP sensor on the MS board??? If you are trying to make it apear totally stock, that will be hard to fake, my sugestion is you will have to use some of the unused pins on the stock connector and have a remote map sensor that you hide in the engine bay, then send the signal through the unused stock wiring to the stock looking ecu... This is an interesting project... i like it!

That extent violates the rules though.

I believe the rules allow anything inside the stock case to be mucked with... as long as nothing outside it is changed.

ah, i wasnt aware of that... so u can still run a vaccume line to it and be ok?

what the hell is sts2 anyway?

That would be illegal. I think his mods to the MS would be required to make use entirely of a completely stock system. So any input/output would have to come from the wires coming into the stock ecu.

so u would have to use the signal from the AFM insted of a map sensor.. i see

Yep, no MAP sensor, just the stock sensors. In my 94 I believe that's a MAF sensor and not an AFM sensor. One interesting bit is you can use "signal modifiers" between the stock sensors and the ECU but I don't believe that that allowance would help in this case.

what is STS2?

STS2 is a class in SCCA's autocross division. Basically it's a street tire prepped class. (you must run street tires but springs/shocks/sway bars are free as are headers, and catback exhausts) There is a provision for remapping the ECU by either hardware or software which means that anything inside the stock ECU box is free, but you must use the OEM sensors or "signal modifiers"

copy that..

I had a friend that had to do something similar to an RX-7 to fit into SCCA rules. He did some pretty impressive work to fit it into the case, but I think the RX-7 already had a vaccuum line running into the ECU, if memory serves.

Here are some pics that I promised. If you want more I can take more tommorow.

http://mason.gmu.edu/~lsnead/ecu1.jpg
http://mason.gmu.edu/~lsnead/ecu2.jpg

I don't see why it wouldn't fit if you do without the on-board MAP sensor (you won't be using it if you go with AFM/MAF anyway).

Do you have pictures of the inside of the case with the OEM PCB removed?

No I dont have pictures of that. But I can take some pics of my OEM ECU case open some time tommorow.