D Prepared Miata Build

The car is EFFING AMAZING! We beat out every fendered car there, and were only beaten by a Kart (that kid was amazing... holy crap). Anyway, Tom had the 2nd fastest time of day and I was 3rd (0.2 sec back). And we're making 114 whp on a good day.

As far as speed gained per $ / time / effort invested, this project is a FREAKING bargain. The car is incredibly fun, and just stupid effing fast. And it was a serious power course yesterday, we ran just about the whole thing in 3rd gear. And it was mostly foot-to-the-floor for as long as you have the courage, and just work the steering wheel. Supercharged Elise? Beat. Corvettes? Beat. Turbo'd Miatas? Yep. And these are pro-class, national trophy winning folks... I'm pretty friggin pleased with that result :D
 
great stuff Muff :D glad to see your little project is putting you up there in the ranks :D and you're not even done yet hehe
 
Sounds great! I've been watching this thread with keen interest as seen below:
60878_708471330861_25010126_39328940_2444222_n.jpg
 
Definitely! Especially since you're a "scant" 5 hours from me. (Central NC)

After reading your build thread though, building a car from scratch is MUCH more daunting than taking an STS car to DP. Still on my list of todo:

1. Wire car car from scratch (underway)
2. Install race seat(s)
3. Have custom roll bar installed
4. Build/buy new motor
5. Install missing cooling system
6. Buy/Install new suspension
7. Fix brakes
8. Machine custom hub rings for new wheels that arrived last week


There's also not much information out there on thse cars. Your miata is the first build thread I've run across. There used to be a miatapower.com that had a bunch of info on it, but it went away before I was really interested in the class. The pictures I have of the ones that showed up at nationals have a LOT of custom work on them.
 
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What wheels did you get that you need centering rings for them?

And it seems like you're on the right path. Having a plan of attack and breaking it down into very small chunks helps stuff like this tremendously so it doesn't just look like one big overwhelming mess is key. And yes, starting with a pretty darn well sorted STS car helped a lot. And honestly, as different as DP is than anything else I've ever had the pleasure of autocrossing, you're probably better off dropping whatever engine you've got laying around and get a handful of events under your belt just to get things sorted at a baseline before you go crazy with the power adders. We're making 114 whp at last count (very healthy stock-rebuilt 2 years go 1.6L) and I'm still having a hard time getting my brain wrapped around the speed.

One of the biggest reasons I wanted a detailed build thread was so there would BE some info out there because, as you said, there really isn't crap for info available about this. It's not like ST and Stock, or even CSP where you can do a pretty cookie-cutter build and get most of the way to where you need to go with just a little research. No such thing exists for DP that I've found. I had also come across the miatapower.com site and it had some tips, but even then it was really vague in detail regarding what went into it, so as this progresses (over a lot of time... with twins due in 2 months, "updates" will likely be very sparse for a while here lol), I plan to go into as much detail as I can.

If your seats are anything like mine, I've got a pretty simple install for them in my original STS build thread if you're looking for ideas.

Again, good luck with the build :)








Moving back to my car, after watching the video from Sunday's event, I'm fairly convinced the stock viscous is all viscoused out. Coming around the sweepers, it really sounded like we were just spinning up the inside tire without really doing much for forward progress. I guess it's time to get the Torsen from the 4.1:1 housing swapped into the 4.3:1 open diff I've got laying around.

That diff served me QUITE well over 5 years of autocrossing, so it's about time to be retired anyway lol
 
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Yep, the plan is to put in a stock motor for the time being. The motor that's currently in the car has a bad scratch on the #1 cylinder. I bought the car with the head off the motor. I've got a line on a local, stock 1.6 to put in it's place for the time being. I've still got LOTS of questions on building a 8500-9000rpm screamer and am nowhere close intellectually to being ready to build it, much less financially. Like you time and money are far from limitless(Hey JRo or Hollis, want to sponsor my build??) so I have to set my priorities.(Sometimes working for the state sucks)

I bought a set of ex-FSAE wheels, 13x7 4x100 5.25" backspace for a... reasonable sum. They came with a set of 20x7x13 slicks that look to be in great shape. I'll probably run those the first event or 2 while we get everything else dialed in. The hub spacing is WAY too big, but they clear 1.8L brakes and weigh something near 8lbs as far as I can tell. The currently wheel/tire package weights about 20lbs and I expect that to go up 2lbs when I upgrade to the 9.5" slicks. Currently with the 7" tires they clear the stock springs by about an inch and a half. I know the slicks like to "walk" left and right much more so than the DOT's I'm used to so we'll see if the 9.5" tires + coilovers will work with my current backspace. I figured worst comes to worse I have have a set of hubrings/spaces machined custom.

Yep, my donor car came with a viscous rear end as well, but I have NO idea what condition it's in. I'm going to deal with that mountain when I get to it. Priority #1 right now is to get it running/driving and being safe. THEN I can work on the go fast part. I'm shooting for the local TestN'Tune which is late February of 2011 as it's debut.
 
Cool, good luck. Just make sure that the slicks you have on it are rated to the weight of your car, or bad things can happen. A lot of times the formula type cars (including SAE) use stuff that's fine for a 600 lb car, but way under rated for a 1800-2000 lb one. But yea, I fear that backspacing may be really close to the suspension with the 9.5s (honestly, I'm not sure they'd fit static, much less under load) without some spacers. You're going from a 7" tire to a 10.1 IIRC section width (with the goodyears at least) tire.
 
I'll check into the formula car vs. GT car thing. Hoosier does not have any published weight ratings on these tires. I hadn't thought about that. I think I'm going to be pretty close on the wheel spacing. I should be dropping an easy inch on width with the coilovers which will make up most of the extra 1.5" in tire.

Honestly I've been focused on gutting the wiring and getting it whipped back into shape. The car was only $500 but man was it a $500 car! I found 51 of these in the car along with 1 bad alarm system, 1 first generation satellite radio system, 3 unknown IC modules, 3 non factory switches in various places and an extra 10lbs+ of non factory wiring.
5601.gif
 
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Since I keep "rubbing" the frame on the ground, it's time for some more serious bump stops. On the front that means... I need to install some bump-stops, period, and on the rear, I need to get some that don't suck lol. With the 195/50/15s, the tires rubbing on the inner fender was our overall bump-limiter (didn't really ever happen except on big bumps), so we never really *needed* bump stops (except in the rear), but even then we were tall enough that it wasn't ever an issue. In 2 events now we've hit the ground at some point on just about every run... good thing the NAs are friggin sturdy. Regardless, I took the suspension off last night to take some measurements:

64621_566695920114_44304805_32925244_6949383_n.jpg


Took the coilover off of the desired corner, removed the spring then re-install the shock. Wrap a zip-tie around the shock shaft at the bottom of its travel. Install the tire and put a jack under it to run it up to your desired travel limit. Take the shock off and the zip-tie stays in place, essentially marking off where the shock travel is. Measure that, add a few mm for good measure (since bumpstops are foam and will compress) and then open the ol' wallet.

I picked up a set of 36mm bumpstops for the rear, and 46 for the front. I've also got a few spacers coming in case they end up being a little too short to quickly "lengthen" the effective bump-stop (really, lengthening the "shock body"), all from FatCatMotorsports.com. I checked Flyin Miata but their selection of bump stops suuuucked, and was ultimately more expensive.
 
You didn't get Keizer wheels did you? My FSAE team used them for a season, they are floppy as hell even with mag centers.
 
Haha, I know they're expensive, we bought 8 of them, 3-piece 13x6, x.x and the first day out they deflected over 1/4" the next year we switched to magnesium centers and they were still pretty floppy. My last year we bough center-lock BBS wheels, I think they were forged magnesium, those were awesome, big difference in car feel.
 
JamesCH said:
You didn't get Keizer wheels did you? My FSAE team used them for a season, they are floppy as hell even with mag centers.
Click to expand...

No They're BBS wheels. There was a set of Keizer wheels available as well, but the offset and size was wrong. (13x.6.5 and 6.25")

Andrew,
What ride heights and total wheel travel distances are you looking at?
 
ride heights are right around 11 3/4 - 12" all around. Hard to really give an accurate reading because the fenders are pulled slightly to keep them from chewing into the tires. I can measure wheel travel for you tonight. Since I've got the suspension apart, it's not a huge deal to do.
 
tpwalsh said:
No They're BBS wheels. There was a set of Keizer wheels available as well, but the offset and size was wrong. (13x.6.5 and 6.25")

Andrew,
What ride heights and total wheel travel distances are you looking at?
Click to expand...

Rock on then!
 
tpwalsh said:
They came with a set of 20x7x13 slicks
Click to expand...

So, I was poking around on Hoosier's catalog and I remembered this post so I decided to do some checking.
Hoosier doesn't have a 20x7x13, but they do have a 20.5x7x13 C2500, which is shown as FC, FM, S2000, DSR as the application. I forget exactly what the C2500 designation stands for, but basically it means the tires are for formula cars only.

Then I checked Good Year's catalog, and they do have a 20x7x13, and the application on those are similar. FC / S2000 / FM. Looks like they're probably the G-19 "Formula" Eagle tires, instead of the 'regular' G-19 Eagle tires for the GT & Production classes.

Am I saying that these things will explode and kill everyone in a 1 mile radius if you put them on? I honestly have no idea, I've never done it or seen the results of it. But It does sound like a really bad idea. On the upside, you can sell these and you've got an excuse to look into some 20x9.5x13s ;)
 
I know its a little off the current stream of consciousness, but I don't think there is a way that you could accidentally release the door latch cable while driving. I tried to purposely hit the cable release with my elbow and I got banged up just trying to get to it. I think there is no problem there.

Now, why is your roll bar so tall? It looks stoopid.























:p
 
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