Son bought second miata project
 

I'm old -my sons 17. He works hard and just bought 91 1.6 turbo project started but not running. We installed new fuel pump and radium rail and now its running and drives pretty good. Almost ready for paint. It has a ms3pro and I have compared it to OGPedXing vids and pretty different-maybe 1.8 to 1.6? Is there a base 1.6 turbo megasquirt file we could look at? His first NA is the 92 with ITB's / ms2. He just hit a deer so 92 is out -he just bought new front fenders to arrive in Jan. He works evenings and weekends to buy miata stuff so I want to help anywhere I can.

Welcome to the forum!!

First thing you can do is check what diff is in it. The early 1.6 NAs (and some 1.8 NAs too I believe) have the small CWP, and don't tolerate decent power readily. The upgrade to a 7in diff from a later NA or any NB is simple, and not outrageously expensive. Check out the DIY and prefabbed turbo forums here - better still get your son to check them out! (spoken by a father with a considerably older son who is still prone to precipitate action!).

Not a MS person, so I will leave that to people who know about that stuff.

Hey bud, welcome to the group! You seem like a good dad, and your son has good taste.

Hit up diyautotune for a base map, they sell the ms3pro pnp that the car might be running. Make sure to hook a timing light up to it and verify timing is in sync as well. Tunerstudio with a few autotune sessions goes a long way to get fueling in the ballpark. Lots to read and learn here as well!

Cal said the dif has been upgraded to the bigger LS, but good note is that the axle seals are leaking pretty bad so we will be taking it out and going through it. Also good to do is checking all the bolts and connections to make sure the project was done well the first time. We found so many missing bolts and nuts on his 92na and already a few missing things on the 91na. I'd never dismiss a comment. Thanks

Thank you! I will circle back to look at what they have available. I am amazed at the resources here. Cal bought a ms3 pro subscription to match his 91na (turbo) and we have the base 1.6 tune, and have been really struggling with tuning the 92na with ITB's with the ms2 that came with the car that he bought when he was 14 (yes all his $) and realize the challenges with itb's are different when using stock intake. The Turbo 91na 1.6 is already running very good and reliable with good idle etc. I don't know the wheel hp but it is quick. I don't see a lot of 1.6 turbo charged. Gingium did one and I need to go back and watch his experience and learned lessons. My hope is that Cal doesn't smoke the 1.6 before we get a good fuel map that covers the turbo afr and ve needs etc. We are just new to turbo and ms tuning. Also- has anyone had the throttle body screws come out and go through the engine? Crazy chasing hp with green backs. . .

It's easy to tell if it's a weak 1.6 diff or a stronger 1.8 diff, the 1.6 diff has "stub axles" that go into the diff and the axles bolt onto that with a 4-bolt flange. The 1.8 dif has your standard CV axles where there is no flange and the axles go right into the diff. I'm sure google could help if you need some picture references.

The main things you can do to keep it from blowing up are:

• Sane, safe, base timing map.
• Confirm base timing on the motor matches what the ECU sees. See: https://www.diyautotune.com/support/...r/base-timing/
• Run a wideband o2 sensor (hopefully the car already has one, if not, stay out of boost until you get one). Look at the AFR on the gauge and ensure it matches what the ECU sees, if not, fix that (search this forum).
• Pay for TunerStudio pro subscription (Tunerstudio is free, but it's like a 1-time $50 charge for a license and that gets you autotune), and run some autotune sessions:
  You Tube

There's of course endless more tweaking and tuning that can be done, but just doing the above should get you a car that runs acceptable and doesn't blow up. Good luck!

This is incorrect. Early 1.8 NAs (94/95) with 7 inch diffs used the two piece axles as well.

Just when I thought that I knew it all..

Thanks!

Yeah, I was corrected elsewhere just a couple of days ago, hence my post up-thread mentions it. Never seen one personally, never heard of anyone seeing one until then, but I was shown a photo and it appeared legit.