Fathom55

Hey everybody,
Figured I'd go ahead and do a formal introduction post. I'm in Houston, Texas and am currently in the process of purchasing a turbo miata from Wayne Presley in Alabama. The car should be here next week, and I'm super stoked. Decided to name the car Tex to pay homage to its new home... And because I love Texas.

Bought this car as a street legal, but track dedicated toy. I've got some experience on track (maybe 6 or 7 HPDE weekends), but never in a forced induction car and never in a Miata. I'm confident my learning curve will be steep.

The car appears to be in great mechanical shape and only needs some basic safety items and brakes to get ready for the track. I'm a bit nervous about the cooling, as the car has a relatively small inter cooler and a brand new OEM radiator. I'm going to dial back the boost and try to run it with the OEM radiator for a weekend and see how she does.

Looks like there's a lot of Texas turbo miatas out there. Looking forward to meeting you guys. First round is on me.

Take care,
Phil

koan123

Welcome to MT and it does sound like you have a solid plan there. At least it has a new OEM rad though I would still consider upgrading your cooling system before going too far.

Also I would expect lacking an oil cooler to be more of an issue on track than the smaller intercooler unless its knocking.

czubaka

iTrader: (3)

What year is the car?

Fathom55

It's a '99 5 spd.

Mark, you think an oil cooler change over an intercooler upgrade is the way to go? Just FYI, the car is tuned to an A/F Ratio of 11.2 under boost, which I consider to be pretty safe.

czubaka

iTrader: (3)

What engine management does Tex have? I don't know if you've got the OBDII testing figured out, but it's a pain for us.

karter74

iTrader: (4)

Welcome!

If you're concerned about the cooling system on the car, a larger intercooler isn't a solution to this unless you're talking about the temperature of the air intake. If you aren't pushing too much power (<220whp), I doubt your small intercooler is really much of a problem.

If you're tracking the car, do you have proper ducting to the radiator? Coolant reroute?

As stated earlier, an oil cooler may be of interest.

Any pics of said car?

Fathom55

It's running a MicroSquirt. I've got dyno outputs with the A/F Ratio and Manifold Pressure. It looks like a pretty safe tune, which is good. I'm certianly no expert on tuning anything...ever... but Wayne has setup and tuned a few of these for various applications before, all with great results.

Yep, OBDII is going to be a PITA. What a ridiculous government driven rule... "who cares if the car can pass the sniff test, our fickle mandated OBDII computer is the only thing that matters"...but I digress.

Wayne tried to set it up so I could swap back to the stock ECU, but I don't have the stock injectors and there's no MAF meter, so the stock OBDII is going to throw codes and run like ***. I know we're allowed 2 "exclusions" on '99s, but I don't know how the OBDII treats those things. I'm thinking I may try to find a guy.... if you catch my drift.

Fathom55

Well, the car is tuned to 235-240whp at ~11 psi. Other than the intercooler, the cooling system is completely stock (with a brand new OEM radiator). No ducting, no rerout. Cooling is at the top of my list after I get the new rollbar installed.

I'll post the pics I've got later tonight. Still waiting on the car to ship!

Braineack

iTrader: (62)

Welcome to the site Fathom55, thanks for joining up!

Chilicharger665

iTrader: (2)

Ducting and reroute, like you said, are the minimum you need to do. My old 2000 overheated in the NM summers bone stock, so I dont imagine a giant heater under the hood helping that situation.

Fathom55

I'll run a search and figure out the necessary steps to get the ducting and rerout (I assume you mean radiator -> engine -> return rerout?).



Pics attached.

Chilicharger665

iTrader: (2)

Yeah that intercooler is tiny. I would suggest hitting up Dem768 for his bolt in Vibrant 350HP rated intercoolers if you want to upgrade. Its only $300 unless he has raised prices.

18psi

iTrader: (76)

is that an obx manifold? LOL yeah, that's gotta be the 1st thing to go

turbofan

iTrader: (1)

Just what I was going to say.

You NEED a new exhaust manifold right away, especially for track use.

Nice job joining up right away though. I had considered that car before I bought mine, it'll be interesting to see if it's as advertised. I'm sure you'll love it!! Welcome to the group!

Fathom55

Link to a thread regarding issues with the OBX manifold?

Cracking problems? Heat? Flow?

Seen OBX exhaust manifolds on other cars that are just "okay". Impressive that you guys can spot one on sight.

turbofan

iTrader: (1)

Search about it. They're very thin steel and known for cracking.

In the original for sale thread I inquired about the hardware and he said it was an OBX.

sixshooter

iTrader: (12)

I wouldn't worry excessively about the intercooler. Its small size will actually allow more cool air to that stock radiator, which will help to keep you out of the woods in the short run.

You will need to add some heat shielding to all of those exhaust parts (after you replace the fail-prone manifold) or the car won't make it through the first ten minutes of HPDE. Even the stock exhaust has heat shielding. You are making roughly twice as much power as stock, which means twice as much heat. The brake master cylinder reservoir will melt and you could have a fire and no brakes at the same time. You will need to shield it to protect all of the brake lines and throttle cable, too. And it looks like the brake fluid needs changing.

The need for a reroute stems from a manufacturer's oversight when re-purposing the engine from a front wheel to rear wheel drive configuration. The coolant flow path does not evenly cool all cylinders. This isn't a big deal at stock power levels but becomes increasingly troublesome as the thermal dissipation requirements increase.

Fathom55

Thanks for the color.

Any harm is running the OBX until it cracks? Obviously once it cracks it has to be replaced because the car will run like ****. Am I missing something more significant?

Did some digging on the rerout. For track application, any additional considerations that need to be made on the change? Will an off the shelf kit suffice?

I plan to wrap as much as I can in the engine bay. Scary note about the brakes failing. I plan to change the pads and fluid before any track time. Brakes are nothing to play with.

18psi

iTrader: (76)

That's about it. It will crack. Fast. On the track I'd expect it to crack in 1 session.

Nothing special about the re-route. Just do it. Very worthwhile mod on a track car.

Fathom55

Wow. That's pretty freakin sorry. I'd be embarrassed to make and sell that product.