mafoose

I have an old MS box that I assembled and ran on my turbo Nissan L28ET for about 3 years.

I no longer have that drivetrain so I want to stick it in my new-to-me 1994 Miata in the hopes of turboing it in the future.

It was built in the most basic of ways (being an old v2.2 box) with no flyback board. On the ignition part, I don't remember doing anything special. I was using the Nissan CAS which was a 6 slot wheel for my trigger input and an HEI module controlled by the FIDLE output to drive the coil (the OG MSnS-Extra setup).

Will this work for the Miata? Should I even bother modding it (such as doing the fan output mods and the spark inversion mods)? Or should I just build a v3 board box? I know for these old boxes you practically have to by a little chunk of proto board to add stuff, it's not as pretty and neat as the v3 proto area.

Can I even do the spark inversion mods on the old board?
Seems like everyone is running the fancy v3 board now (or the PNP).

The car also has AC, which I saw is also an issue (somewhat). I would much rather stick a different switch type TPS (I was using MAPdot on my setup anyways) and use that to control the AC. With a little solenoid valve as a throttle bypass that I could use for cold starts (ha Arizona!) and for when I'm idling with the AC on (using the WOT and Idle TPS switch positions respectively). But then I ran into the post where someone suing MS for everything but idle control, and lets the stock ECU do that. If I were to do that, do I still have to leave the AFM (or is it a MAF on these cars) for that to work?

Ideas? Thoughts?

Joe Perez

iTrader: (8)

Wow, that's a lot of questions.

If it were me, I'd start fresh with a 3.0 board. It's bad enough de-modding and then re-modding any board, but with a 2.2, there's not as broad a knowledge base these days.

I use MS for everything including idle. Granted, I don't have A/C, but with an appropriately sized air solenoid and the circuit I described in the sticky, I think you'll be fine.

You'll be fine with the switch TPS. In fact, it'll simplify the A/C cutoff portion of the circuit, as you won't need a relay driver.

mafoose

Do I just get a switch type TPS from an earlier Miata?
I might be able to swap boxes with my dad, he's got a v3 box in his 76 280z that I turbo'd about 2 years ago. He's not doing anything fancy with it, so I bet he wouldn't mind.

I was thinking something like this, if not bigger:
1/4" Electric Solenoid Valve 12-volt Air, Water... BBTF - eBay (item 300330380553 end time Aug-13-09 13:58:14 PDT)

I could then build a little flow restriction to bump up the idle to a sane amount if it's too high.

Joe Perez

iTrader: (8)

Sorry, I missed where you have a '94 and assumed from your mention of a switch TPS that you had a 1.6 engine.

Just use the TPS you've got.

mafoose

If I use a potentiometer type TPS I'll have to have MS drive the relay (and basically the AC). I'd like to keep MS out of that.

Also, if I start anew, do I just order a basic v3 kit from DIYautotune (plus pullup pack and fan control mod)? I've assembled about 10 boards, and they all have worked without issue so I know I can save a little and build it myself.