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My NA becomes a track car (Build thread)

626K views 3K replies 292 participants last post by  dbuilt 
#1 · (Edited)
**Prepare to see the worst paint condition you've ever seen on a miata. Just fair warning. Yes I’ll be getting it painted soon. **

I decided there's no time like the present to start doing what I've been dreaming of: time attack in Miata Challenge. Car stays street legal, and I drive it a lot, so there's still a need to balance track needs with street needs, but the car needed a few things to be properly ready for track abuse.

First off, needed a more serious driver's seat. Found a great deal on CL for a Sparco Circuit (FIA) with normal wear and tear. Mounting involved bolting the sidemount brackets to a modified Corbeau bracket, fixed position, no slider. This seat is a pain in the a** to fit due to the dimensions at the top, especially with a soft top, but I made it happen:










This made it possible to move my old driver’s seat – a Momo Start – to the passenger side for instructors. The Sparco is crazy tight and rigid, I literally feel bolted into the car in it, which is pretty cool. I paired a quick release hub with my NRG steering wheel about a year ago, never really used the quick release much, but now I am really relieved that I have it - getting in/out over the high sides of the Sparco Circuit is nearly impossible with the steering wheel in place.

Next was the exhaust. My old setup was a 3” dump at the rear axle. It simply wouldn’t have any hope of passing sound at Laguna Seca. I had the turn down tip cut off and 3” mandrel pipe ran out to the back above the diffuser, exiting out the side of the rear bumper behind the wheel. The muffler has a removable silencer, which will be crucial for tracks with sound limits.
Old Exhaust:

New Exhaust (will get to the wheels in a minute):


Oil cooler is basically a necessity for a turbo motor on the track. Mocal thermostat plate, FM sandwich plate spacer, push-lock fittings, aeroquip hose, Trucool oil cooler. While I was in there I added the tow strap from Saferacer. Still need to add a tow strap for the rear. Just took one quick crappy phone pic before putting the nose back on:

Bumper on, tow strap hanging out:


Found a guy on this forum who offered to trade me his Torsen for my Open diff + cash, so I scored a Torsen for $300. Along with that I got to swap my line for his SS brake and clutch lines for $50. Drove up to his place in Irvine and swapped it all on the side of the road:


The big purchase was wheels and tires. Need a dedicated set for tracking (already have a street set and a autox set), and was tossing between the TR wheel or other cheap 15x8s, and then came across an amazing deal on CL for brand new, still in the box 15x9 6ULs for $600 with all eight 949 valve stems included. Could not pass it up. Paired them with Hankook RS-3's in the tried and true 225-45-15.
My rear fenders are flared and the front fenders are extremely pulled to fit my autox and street wheels. The result is whereast these 15x9's barely fit on most NAs, they actually look sunken in on my car, but that is great for aero, aesthetics aren't the priority here:








These are seriously meaty. Grip is ridonculous for a street tire. They make my Azenis feel like all seasons.
Rear view with the top up:


Rear View, top down (I'll be running top down for MC - I'm maxed on points for Mod class, so hardtop is not an option, plus I prefer this for the fun factor) :


Last, attended a dyno day to do a little check up on the motor and make sure it's still strong. I also set up an in-car switch for high-boost and low-boost. I'll be running the low boost on track for engine longevity and maximum fun.
Almost two years ago I dyno'd at 206 whp / 179 ft-lbs. Boost hasn't been changed (10psi), but better exhaust now and new plugs/wires/PCV/etc. Put down 207 whp / 208 ft-lbs. Strong.
As for the low boost for track, I'm having trouble getting the turbo to spool at any lower than 7psi. I was hoping for 4.5-5 psi and ~150 whp, I'm not sure if the exhaust is too free-flowing, or what, but with the wastegate full loose it still holds at 7 psi, which put down 185 whp / 180 ft-lbs.



That's about it. Car is pretty much ready to go for April 17th at Buttonwillow. Still need a tow strap on the rear, and I have to pull the rear diffuser off in order to fit under the 15.5 point limit for Mod class. I'd also like to try to get the low boost setting a bit lower.

-Ryan
 
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#4 ·
Nice build. Don't worry about the find speed in the car, but rather look into you optimizing the car for your needs. Bryan Wood is a tough cookie to beat in Modified class, so I'd use him as the benchmark. Also, don't worry about losing the diffuser, you won't lose too much lift reduction from not having it.
 
#5 ·
Thanks. I've just focused on the things that were necessary for track use; needed another race seat so I could have an instructor ride with me (used to be only one seat), braided lines for safety, oil cooler and dedicated wheels/tires for reliability, tow strap required, etc.

I'm going into this a rookie, and focusing 100% on learning, building skills, and accumulating seat time. Now that the car is ready, it'll just be upkeep and maintenance for it.

-Ryan
 
#23 ·
From what I remember, the HT doesn't add any points. Why wouldn't you add it?

Anyways, great looking car!
For some reason I thought it added a point for the aero, but I was mistaken. Still, my outright goal here is not to be the fastest, it's to have fun. Running top-down is really really fun. I'm on a budget, so if a hardtop falls in my lap for an unbeatable deal, I'll go for it, but I'm not in a hurry.
-Ryan
 
#22 · (Edited)
The track day was great!

Camping at the track, budget style:




This being my first official track day (I don't count Miatas @ MRLS), the first 3 sessions were really just getting the feel of things, learning the track, getting comfortable etc. Lap times dropped from 2 : 35 for the first session to 2:17 by the end of the 3rd.
The 4th session is when I started feeling like I was connecting corners together and carrying enough speed all the way through to use the whole track on exit, etc. But then an intercooler hose blew off on the first lap that felt fast, so I pitted and fixed it and got back out on track in time for just one out lap plus a flying lap. I did the flying lap at 3/4 throttle to just get a good lap in without the hose coming off again and did a 2:13.

Back when I upgraded to beefy hose clamps, I left one old clamp on because it was a biatch to get to, and naturally that's the one that failed me at the track. That will teach me. :)

All in all though, I had an amazing time, and the car felt great. All of the big dogs who usually run in Unlimited had their Mod class cars there and were running in my class. Andrew Savington did a 2:09.5 in the same session in a fully stripped and caged miata on 225/45 NT-01's, and his dad in the same car was doing 2:12's, so I am pretty happy - there lots more left in the car, but with my beginner-ness and not getting more than one lap in once I was comfortable with the track, I couldn't have asked for more!

Some highlights:

-Getting a point-by by a yellow S2000 coming out of the last corner onto the front straight. He moves off the line and points me by but doesn't lift and we end up drag racing side by side down the front straight. At my low-boost 185 whp, I still pulled a car length on him by the braking zone for the first corner :)

-In the 3rd session spending a good 3 laps just matching speed with a white turbo miata and flying around the track. We ended up finding out in the 4th session once I got some confidence that my car was a lot quicker than his, but just cruising around at a 2:17 pace with him was really fun.

As an update, I added a fire extinguisher to qualify for the -0.5 points in MC:


And I removed the rear diffuser so that I didn't take the +1 point in MC for rear aero. This and the fire extinguisher bring me down to 15 points so that I am in Mod class. I also added the rear tow hook, which I need to fab a little hook for so it doesn't hang down:
 
#29 ·
With all the craziness of being at my first track event, I didn't even think to use the GoPro until the final session, and I had had the intercooler pipe blow off in the previous two sessions, so I was taking it easy and just seeing if it would hold.

Video is of one warm up lap at maybe 3/4 throttle and passing a single lonely S2000, and then on the following lap I start to push a little and it blows off again and I throw my hands in the air.

The camera location is crap. My rollbar mount is faulty so this was my only option.

http://youtu.be/icYcNvU3zyM
 
#31 ·
Nice build. Im digging the diffuser too!

Quick question, Im kinda liking that dash guage pod, which one is it, or were did you get it from?
Thanks!

It's just the regular black gauge pod by autometer: http://www.autometer.com/cat_mounts.aspx?sid=49
I think I ordered mine from Summit Racing.

edit: I might have misunderstood which gauge pod you meant. If you mean the dual pod in the center of the dash, it's a dual pod for a mustang: http://www.summitracing.com/parts/ATM-10001/
-Ryan
 
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