Building an engine for STR
 

Due to the oil pump grenading during the first track day of the year I am forced to rebuild the engine. The vehicle is a 95' with a JDM VVT engine which has the 10.5CR pistons. Current powertrain modifications include
-RB header
-Open air filter at end of NA crossover(It needs heat shielding)
-Magnaflow oem fitment cat
-Roadstersport cat back
-Running a diypnp MS1 with VVT controller
-COPS

Wanted to get into Solo this year and I just bought BFG Rivals so STR seems logical. I am curious what internal engine work will disqualify the car from STR.
Current plan of attack is a BE oil pump, 949 dampener, and balancing the rotating assembly so the oil pump grenading is not even a remote possibility anymore. Stock pistons/rods, a hand blended multi angle valve job. New bearings would be installed as well.

Need to go back to the 95 engine to run in STR. Car would be perfectly legal in CSP though, unless there is a difference with the JDM VVT engine that isn't allowed such as the cam profile being different from a USDM VVT engine.

How is an NA miata even competitive in STR without being able to run the newer engine? Is there a class for what is basically a CSP car with Street tires?

Back up a second. NA car + VVT motor is CSP or higher. Not STR legal. If the Chassis is a 95, then it needs to have a 95 motor. You can make a very VERY minor changes, but nothing really substantial. For instance the 94 pistons have been superceded for the 97 ones which is a 0.5:1 CR bump. No motor swaps, No port work, no BE gears(though I don't think anyone would care, but that's another discussion), no balancing. STR is STOCK internals. If you want to move to use the VVT motor in the 95 chassis then if you go back to the stock USDM 01-05 internals, you'll be CSP legal. There you'll have some more freedom, but not much. That's still stock internals, but porting is legal up to an inch, all exhaust and intake are free, etc.

Rules: The Sports Car Club of America - Solo

Locally some to most groups run a street tire class. Any class, 140+ treadwear rating tires only. Then it'd be CSP-T

Accepting as configured the car is CSP or higher, the pistons are oem. I beleive available as stock replacement parts and available to anyone. This would still be a fail?

Yes, its called run CSP and don't complain that you're slow just have fun.

It's all just for fun, when you lose sight of that...this all becomes pointless

Holy shit can you please write a letter the the SEB explaining how you don't care about being competitive and that its all just about fun. I think they need a dose of that with the whole stockmageddon thing.

At at local level its all about fun. National level is serious business.

Don't waste money chasing after S2000s, you'll never catch up.

Dumping 30k into a CSP car; however...

That depends, if he's in the north east a well built NA with a halfway decent driver should be able to take top honors. As a crappy driver with a half built car at the time the closeness of me to the leaders at national competitions in the NE was just silly.

If it's all about fun, then why does anybody care what class they run in? Build the car you want to own. When you feel like knocking down cones do it in whatever class they put you in.

In the phoenix area csp miatas are always top time and in str the miata is absolutely competitive with s2k

The NA and Early NB Miatas can compete in STR, but it is course dependent. A highly transitional course with limited areas to use power gives the lighter Miata a slight advantage. But on a open course with flowing sweepers and "real" competition the early Miata will more times than not be left behind.

The truth is UNLESS you plan on running at the National level who really cares about having "the car." Just build the car how you want it...show up at local events and run it where it fits.

+1, In our area SCCA is only one of 5 clubs that run AutoX. I go to BMW and S-2000 events, more runs per event. They class all < 2 liter on TW > 140 all together. I don't win, for me the driver is the limiting factor, not the car.

They aren't. Neither are the NBs really.

Locally the NA is, but its down on power. The NB should still be competitive, even the car to beat, if someone would just build it. Its advantage has dropped a bit with the z2 and the rival coming out, but it should still have an advantage with the magical pixie dust tire in the wet and when the 225 rival comes out in the dry. A serious effort is going to take 2 very different setups and sets of tires for wet and dry. I shouldnt really say that the pixie dust tire might still be the tire to have in the dry.

The NB is barely competitive with an NC in STR, how do you expect to beat an S2k?


Maybe locally they are, but we have too many S2Ks with capable drivers here for an STR miata to be worth it.

I donno, I've raced against some of those nc area str cars, if I wasnt a medeocre on a good day driver I would have been a lot closer than 2-3 seconds off the leaders. Especially since my car at the time pulled like a 1.6 and at both events the surface was against me, at devens it being like 60* out and I being the only car in STR on kooks, and at jersey just being unfamiliar with it and fighting a monster push.