New Here! Want to turbo my 90.
 

Hey,

I am new here and to Miatas. I recently bought a 90 model. It has Tein springs, adjustable KYB shocks, chassis has been seam welded, weld in 4 point roll bar, OPM bushing kit, OPM strut bar, header, exhaust, HKS intake, some other things.

I have been researching and know 90's (some) have short nose cranks, mine does. Now I have been also looking at Greddy kits and like the price and sound of them.

I have some questions. Can a short nose crank motor handle a turbo?

I want to track day this car, mountain runs, autocross, etc. How reliable will it be? Can it safely go to 7k rpm?

What is needed for tuning for a basic Greddy kit? Anything? I want to be as basic as I can, with a small amount of boost and gains, I hear it adds 30hp in stock form? That is fine for me. I want a little extra power, and stay very reliable.

Any help greatly appreciated. Thanks!

Simon

This thread will be extremely helpful to you. Read it and then ask questions it doesn't answer.
Yes you can safely go to 7000 rpm.
Short nose can be safely turbo'd.
Make sure you do the loctite fix on that pulley before it destroys the front of your crank.
Nice suspension setup btw.

The short-nose crank failure is not directly related to the amount of power produced. If you're worried, I'd search on M.net forums and their garage section about the Loctite fix. There are plenty of short-nose cars that've survived for a long time and improperly installed long-nose cranks that have died quickly.

Yes, the car can safely rev to ~7250 RPM fuel cut-off, though, as with any car, I wouldn't sit there at redline all day long. Frequent visits, though, aren't going to hurt it, and that's why Mazda chose that rev limit.

Yes, the Greddy kit will add ~30-40rwhp in stock form, the problem is, several parts of it are unreliable unless modified. Search on "relief cuts" for the manifold flange, upgrading to stainless, higher-grade hardware, solutions to the stock rubber and plastic crossover that will fail (you could build or buy a metal crossover replacement, but for that amount of effort and/or money, you might as well get an intercooler).

Also, unless you want it to feel dog-slow when running in vacuum, you'll want a timing retard device that allows you to run stock timing but pulls/retards when in boost/higher airflow.

Cool thanks for the quick replys. The kit does not come with a intercooler right?

I will be searching around here I have found a lot of good threads.

No it doesn't come with an intercooler.
A board member named Stripes sells the piping for an intercooler kit though. You buy your own IC, which he can suggest as well as your own couplers and T-bolts and bam you've got an IC. He used to sell the whole kit but now offers just the pipes so you can source your own parts cheap if you want to, like sub$100 ebay IC which will work just fine for what you want to do with your car.
Search for Stripes Intercooler.

Cool thanks!

Yeah, ok.... tell us that after you've had the kit on a few months.:rolleyes:

Can you get only 30hp? You need to take a ride in somebody else's car first before so set your goals. My 2 cents.

Kmag

My rev limiter is set at 7500, so yeah 7K should be safe :)

For what I do, a lot of power is not needed, and I need something reliable. I have friends with built DSM's and RB 240's and all with high HP numbers, and it is awesome, but I need something that will make me smile, and is reliable. I know sometime I will want more, but I will hopefully be using all the money I have with autocrosses, track days, etc.

Thanks for all the input!

Ahh, well you can safely get more hp out of a greddy setup. Very reliably so, its just going to cost a few more coin.

Dont say you dont want more hp because it wont be reliable, say you dont want more hp because you dont want to spend the money =P.

If you TRULY want ONLY 30HP, FORSURE, maybe ITBs and a standalone ECU would be a better idea? Better throttle response, simpler, possibly more reliable.

Yeah, I was thinking maybe IRTBs or an M45 JR supercharger kit would be more in line with his goals.

Even if you are only after ~30whp over stock, get the I/C anyway. It will allow you to run more timing and make the car more pleasant to drive off boost.

I think he's got a point. If you're looking for only 30-40hp gains + rebliabilty, I think some NA tuning might be your best bet. Headers, exhaust, intake, and chip. That'd probably get the power you're looking for

IRTB isn't the easiest setup to get going, and I doubt you'll get 30whp just from bolting them on. Add in headers, cams, ECU ... etc the greddy kit looks like a slam dunk.

Well, it does, unless you're the kind of driver that puts a very high value on second-to-none throttle response and are not entirely concerned with ultimate power.

Well I will TAKE more power, but for the money it seems like Greddy is cheapest. I was just saying the 30-40hp gains was fine. Not looking to have like 300+whp or anything.

did I just hear a "meow"?

Simon, I suspect you really need to drive a few different Miatas to get an idea of what you like. You may totally detest the lag of the Greddy turbo or you could love it...it could really go either way.

Or you may find that you love the JR M45 supercharger kit...or the Fuji Racing IRTB kit.

I think spending ~$1,500 on something you may not like is risky.