I'm looking at buying a local 1990 turbocharged miata and it has an MSpnp If I want to swap in a +94 1.8l engine will it still work or do I need to upgrade the MSpnp to the corrisponding year engine? I did a search for any relavent info but came up empty, so figured I would throw this out for the community. Thank you, PAul

it will work fine. you would just need one mod for the variable tps and that is it, iirc.

nice S/N

It's fine, there will be some software tweaks to make if you use the 1.8 throttle body. And of course it will need to be re tuned.

You will want to do the TPS hardware mod if not already done.

Thanks guys for the quick replies...much appreciated

paul

Are you planning to swap the turbo too? Cause the exhaust flanges are different on the 1.6 and 1.8. The turbo manifold won't line up.

I did just what you're talking about to my old car and once I had a good tune goin on it, it was great. Make sure when you get the new engine in to ground it well. The 1uf cap mod detailed on this board also helped me as did upgrading to the hi-res code. The car was noticeably smoother once i put the new code in. And the tps as said before enjoi

Aye, Im looking forward too the swap, assuming the guy will sell for a decent price... but I will know Tuesday. If not, then i will start off by buying a 94+ and put together my own kit.

Thanks all for the help, and pointers.

Paul

Just my 2 cents. If the motor is good, I wouldn'd change it till it went bad. There is usually only 20hp diferance.

But thats just me.

Drive it like you stole it. lol

I totally agree Todd. It depends on your goals of course, but on stock internals I don't see a dire need to swap to the 1.8. With the 250+ rwhp and 232+ rwtq we're pulling out of this 1.6 with the BEGI S3 kit and MSPNP it's perfect for what we built the car for which is AutoX, a bit of all around butt-kicking, and occasional track toy. I've tuned alot of Miata's, and I've yet to have a 1.8 car with a well enough engineered turbo kit on it to outperform this 1.6 both in boost onset and total average/peak power. I'm not saying they can't as I'm sure a well engineered setup can likely outperform a 1.6... I'm really just trying to say if you've got a decent 1.6, there's alot of potential there. If you're not out to build a total monster you've already got a good motor, and there is a bit of a monster inside with a proper turbo kit.

But, to answer your original question, if you want to use the VTPS on the 1.8 it will need a mod to the MSPNP. It's simple and cheap. Or you can run it like it is with no TPS just like on the 1.6 for now and do that later, with a bit of downtime. (Contact websales at diyautotune.com to setup that mod if needed). The map is different for the 1.8 for a couple reasons, one it's a different motor obviously, and two it uses a different idle valve at a different frequency. You can use the firmware and .msq from the appropriate year MSPNP as a base, if you use your VTPS this will be fine. If not a few settings in the later MSQ will need to be tweaked to work properly with the static TPS reading on the MM9093 box. Then just use the CAS and ignition system from the 90-93 car. You could use the later system, but it will help you avoid some wiring this way....

__________________
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....

if I could do it all over again, I'd probably just leave the 1.6 in. However, the additional off-boost torque from the 1.9l '99 motor is nice, even with the =/-8.8:1 static compression. I scored a 99 motor, trans, and rear end for $740, so I went that route.