STS Autoxer gets sick of being slow and goes turbo
 

Hey Everyone,

Long Story (scroll down to Short Story at bottom if you don't like reading)

Current Set-Up: 90 Silverstone Miata 52,000mi. N/A all stock other than fm sways and star specs on c1m's, learned to drive it as is fairly consistently and decided more power and suspension are needed.

Backstory: I've been running with the BMWCCA for a while now and have just been doing small reversible mods because its far too nice to hack up. But, I'm an engineer and naturally inclined to tear things apart and make custom parts, not to mention I'm sick of getting passed by friends of mine in their high horsepower bmws. So, two days ago I got an offer I couldn't refuse and took the first step towards a slow cheap project and bought myself a 94 motor (no history but got it for a song and a dance). This is going to be the first motor I build and hopefully will also be the first step towards a stripped-down-x-class-bmw-killer miata.

Plan: I'm going to build the motor first refreshing all the seals, bearings etc and doing the FI mods such as coolant re-route, high flow fuel rail, injectors, forged rods and pistons, for future turbo I'm thinking FM no electronics turbo kit and MSPNP engine management. Goal is around 300 hp hopefully 250+ torque and then when the motor's complete i'll buy a shell to put it in and keep going from there.

Budget: Willing to buy the right parts to get power and reliability, but not about to shell out more than I have to, money doesn't grow on trees, lets say around $1,500 for internals and maintenance parts on the motor. (I know the fm kit is 3,000 and MS PNP is 600 so those aren't included in the budget yet, I'll be saving up for those while building the motor)

That brings me to this forum, I've been on Cr.net and miata.net, they have great resources for various things, but for FI I had a hunch this was the place. I'll be asking tons of question and am open to input from anyone on the plan etc and will most likely document the process in the form of a build thread once things get going.

Short Form

- Have a 90
- Bought a 94 motor
- First engine build
- Planning on FI
- Goals: 300HP, reliable, beat bmws.
- Using forum to do homework before wasting money
- Hi. Please don't yell at my NOOBness too much.

Thanks in advance for the help.

Hey x133, welcome to MiataTurbo.net

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Welcome in.

Can't wait to see the build thread!

If autox performance is impt, I recommend the GT2560 turbo. If street response is paramount, I recommend the GT2554.

Save money, buy my used BEGI manifold and divorced downpipe.

Welcome David.

2560 will be running out of steam at 300hp, and since we're talking track use, he'll want a larger turbo than that anyway. For that power level I don't know that you'll get away with $1500 for parts; plan on upgrading the oil pump it'll end up grenading on you. A reasonable plan would be to look at Trackspeed's built longblock part list. I will eventually be doing something similar power-wise but I'm still years away from redoing engine internals.

Depending if he means wheel or crank hp.

A 250whp (300 crank) will easily run with any m3 power wise, especially when paired with the right suspension and tires.

Yes going for 300 crank 250 wheels from what I read that's the limit of stock internals so I figure with cheaper forged internals and good fuel management it should be fairly reliable.

Also I am not planning much track use if any at all, autox is the primary target so a quicker spooling turbo will outweigh any high power gains I was focusing on either the 2560 or 2554 for this reason.

That makes sense then. When you mentioned being passed by your bmw buddies my mind jumped to track events.

Ah yes makes sense by passed I was meaning they had faster times cause they can mash the pedal and pick up 2-3s on the short straight aways where my stock Miata is lucky if it gets into power before I have to brake again. Although it is good insight to consider track performance because I live quite close to englishtown so thanks for expanding my view.

Below is a dyno of what my stock 94 made at 9psi with a GT2554. The low end response was amazing on it.
https://www.miataturbo.net/attachmen...ine=1320679532

That's a nice looking plot, what sort of intake, exhaust set up were you running? Did you have an intercooler?

It was a Begi S1 kit roughly. I had the small intercooler and then the cold air box for my intake. I had a 3inch Enthuza exhaust from the cat back.

The only thing is that the 2554 will max out about about 225hp on our cars. Getting much more then that out of them is a pain as they just start producing more heat instead of power in the upper boost levels.

Welcome, x133!

Ok so after tearing the motor apart it seems I got lucky with this gamble for 100 bucks I got a clean block with nice smooth cylinders no marring or scratches and a beautiful crank, every bearing surface is clean and shiny. On top of that the only defect seems to be that the ports and tops of the pistons have a nice build up of burnt fuel and a little oil.

That said, with my goals I think the fm no-electronics kit with the t2560 is the way to go should get around 250whp and Im going to run a megasquirt standalone and denso 450cc injectors with 949 fuel rail and coolant re-route.

So, this brings me to the more impending purchases:
1) An engine rebuild kit that includes all gaskets bearings pistons rings etc (any recommendations? rock auto has a kit at 360 that looks promising)
2) Water pump / timing belt kit
3) Scat forged rods
4) OEM pistons with tri-coating
5) Replace all bolts as needed
6) Is a stronger oil pump necessary at these power levels? They all seem very pricey with unproven results from what I've read ... maybe I need more research sorry if i'm a noob

Thoughts?

I'm in the process of cleaning all the parts I can right now with a simple green bath and scrub brush, but I'll prob take the block to a shop to get decked and tanked then I'm going to hone it myself (unless the shop gives me a better deal than the 25$ hone I bought). Lastly, I want to keep head work to a minimum and everything looks good, but there is some burnt oil on a couple of the cams and I can't really tell the other stuff without tearing into it. Is it worth cracking it open and replacing the springs and seals, or should I just take it to a shop and let them tell me how it looks?

Thanks in advance.

Oh and a pic for reading all that:
https://www.miataturbo.net/attachmen...ine=1320899804
*The crankshaft pulley gave up shortly after this pic and the crankshaft was tetrised in to complete the line ftw*