1990 Fire Orange Miata, needs help to decide its future
 

Hey Everyone,

My name is Eric and I reside in SoCal for the time being. I currently drive a 1990 Fire Orange Miata (repaint that faded) with 148k. The car has few goodies such as:

KYB AGX w/ Mystery lowering Springs
MazdaSpeed Header
FM exhaust
Airinx Filter
SnugTop Hardtop w/ Lexan window
HardDog M2 sport Roll bar
... etc

I do need some help deciding what to do with my motor. I am having the most difficult time choosing between N/A or Turbo. The compression of the motor is not great, cylinder 1 is at 120psi and cylinder 2,3,4 is at 110psi. I have read in various post that if the compression is steady then turbo it. The term steady is very vague to my understanding, I have searched a little but not enough to answer my own question. Is my car worth turbocharging?

Thanks for reading!

Rust.E

All cars are worth turbocharging. Are you worth helping though?

Post some pics of this orange machine. I want to views it with my monocle.

Every car should have a turbo.

Don't even attempt N/A mods. You have already done what gives the best results and those results are near nothing.

Ah, I remember when my car was stock and I thought the air filter brand was worth listing... ;)

Naturally aspirated mods to miata motors are a complete waste of money in terms of dollar per horsepower ratio compared to boost.

If your motor is down on compression, it could still hold boost for many thousands of miles. I would suggest that if you can afford to swap a replacement motor in when this one goes, then yes - turbo it tomorrow and win. If it's your only mode of transportation and all you have is $2000 and you're asking us if you should spend that $ on a turbo... probably no is what I'd have to say. If your motor is already showing signs of weakening, boost will accellerate its death.

Put a turbo on that shiz. Worst case scenario is you have to swap motors which is a very easy and cheap thing to do.

I think stock compression should be in the 180 range... down at 110 is pretty weak. Even a set of full-ballz NA boltons will yield about 110-115whp in a 1.6, so good luck.

There is a good/basic/complete turbo kit that nets about 150whp for $2k from Bell Engineering. The kit is easily upgradeable over time as your budget allows.

You can DIY a turbo kit for $2k, but it will take time, and it will mean not a penny is wasted with experiments, so you have to listen to us and buy what we tell you... also, almost all of it will be used parts.

Don't forget to budget for a clutch when moving past about 5-6psi... if your clutch is already a bit aged, plan on it sooner. You can get ebay clutches for $200, or an FM for $400.

Also don't forget that you'll still need to pass California smog, and I think BEGi is the only one who sells a kit with a CARB sticker besides Greddy, and you really don't want to go there.

Stock Greddy? No, wouldn't want to go there (again), but someone's used Greddy kit can be a cheap, viable starting point.

Then the only trouble is modifying the Greddy/Begi kit in a way that still appears "stock" to the smog tech. :giggle: