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Started last year on my '99 5 speed Miata for STR. 

Pleased so far with 560 lb front and 390 lb rear springs with Tein Monoflex coilovers.

Racing Beat 1.125" front bar and OEM rear bar.

15x9 6UL rims and will be switching to RS-3 225 45 15 tires.  Did not care for the 225 45 R1Rs at all in '09.

Racing Beat Header, Roadstersport midpipe and muffler along with a homemade coldside intake.

Will continue to use OEM Torsen rear end.

geewiz,

I have a '95 Miata that's technically in XP, though it's nothing like prepared enough to compete there.  It's intended as my track car, and it has (or will soon have) the V8 Roadsters tubular front subframe, which pushes it into XP.  Other than that, it would be in SSM due to internal engine mods, but it still isn't developed enough for that class.    That's why I'm looking to run (a different car) in STR.

What have you done to your XP Miata? 

skeeler:

What have you done to your XP Miata? 

Not to threadjack: lots. built, supercharged 2.0L (>300 horsepower), some aggressive nonreversable lightening (1975 pounds, no windshield), etc. It's a FAST car, but still can get a lot lighter (heck, it still has doors!) and needs a better-sorted suspension to reach it's full potential. Has given Fred Zust a run for his money before, and could do so again with some work. PM me if you want more info.

Now back to STR :). Has anyone actually put 235/40/17 (9.5x24.5) or larger tires on a '90-05 miata with STR-legal fenders? I wanted to fit the dunlop star specs but couldn't justify experimenting with expensive wheel & tire combos for this car since I'll probably be running the CSP car at major events. But if it wasn't an *experiment*, I could buy another set :). Some people on Miata.net think it's possible but I havn't seen concrete proof and from my experience fitting 275/35/15s I can't imagine how it would work. But if it does....then lookout NC guys :).

-- Glenn

geewiz:

Now back to STR :). Has anyone actually put 235/40/17 (9.5x24.5) or larger tires on a '90-05 miata with STR-legal fenders? I wanted to fit the dunlop star specs but couldn't justify experimenting with expensive wheel & tire combos for this car since I'll probably be running the CSP car at major events. But if it wasn't an *experiment*, I could buy another set :). Some people on Miata.net think it's possible but I havn't seen concrete proof and from my experience fitting 275/35/15s I can't imagine how it would work. But if it does....then lookout NC guys :).

Maybe try 245-35-17 Toyo R1Rs? 

Hey you NC drivers,

Do you think that the MS-R underbody bracing and FSTB would be of use in STR?  The reason I ask is that the car I'm likely to buy will be a 2006-2008 5MT, and I'm wondering if I should go out of my way to find a 2007 so that it is legally convertible to the MS-R spec.  After ST allowances, I'd still have the the FSTB (not stock on non-MS-R 5-speed cars) and underbpody bracing.  Oh, and the oil cooler.  2007s are harder to find than 2006s. 

Thanks for your help.

skeeler:

Hey you NC drivers,

Do you think that the MS-R underbody bracing and FSTB would be of use in STR?  The reason I ask is that the car I'm likely to buy will be a 2006-2008 5MT, and I'm wondering if I should go out of my way to find a 2007 so that it is legally convertible to the MS-R spec.  After ST allowances, I'd still have the the FSTB (not stock on non-MS-R 5-speed cars) and underbpody bracing.  Oh, and the oil cooler.  2007s are harder to find than 2006s. 

Thanks for your help.

You need an '07 for doing the MSR conversion, as STR inherits the stock class rules for package conversions.  For an '07, you will also have to install the oil cooler and SV rubber steering wheel.

Parts are starting to pile up and I am starting my wife's S2000 build this weekend.  Doing the diff and shocks/springs before the first event on the 24th.

BrianGT,

Yes, I know you need the 2007 to do the MSR conversion.  I said as much in my post.  My question is, do you folks with more autocross experience think the bracing and oil cooler would be of significant help in STR?  

I've found a good deal on an '06 and what I think is a very good deal on a very-low-mileage 08'.  I can't seem to negotiate the '07s I've found below the price of the virtually new '08. I'm trying to decide what to do.

glagola1,

Thank you for your informed opinion on this topic.  Would anyone else like to add theirs? 

I am with glagola1 on this.  I have no plans on running any braces on my 06 5spd MX5, keeping the weight down to a miniumum.

 BrianGT,

More detail on what you are doing to your S2000 please   Spring rates, type of shocks, what diff, and what else? 

The 255's will fit on the MX5, I have run them, they will fit (fenders must be rolled completely flat, by a professional).  But, to do so, I need to keep the ride height higher.

Big question.  What is more important, maximum tire width, or lower ride height (plus shorter gearing of the shorter tire)?  Theories?  Experiences?  All opinions are welcome.

Jeff, 

Brian will be on Motons and OSGiken diff. Not sure what he's doing for rates yet.

You are going to need all the power you can get to keep up with the S2000's so I'd be on a shorter tire if I were in an MX5.  

SerNick:

You are going to need all the power you can get to keep up with the S2000's so I'd be on a shorter tire if I were in an MX5.  

+1

If I were building an NC for STR it would be on 245/35-17 Toyos.

Jeff,

I don't think there's one clear answer.  Most likely it'll be course dependent.  On a fast and flowing speed-maintenance course, such as the great ones you've helped make our region known for, I  think the 255 may be the way to go.  On a smaller course where there's more acceleration zones, maybe the shorter tire is better.  Have to test both a bit to see.

Has anybody got their STR car together enough that is consistently beating a top-flight ST Civic?