NASA drivers, thoughts on Kit Cars in TT?
 

I know we have quite a few guys here who are running Miata's in TT (E correct?).

Reading through the rules, it states already unclassed kit cars/purpose built race cars will default to TTU until individually reviewed by the NASA TT director.

I'm strongly considering building an Exocet next winter and I'd eventually like to get in to TT. Obviously it would get murdered in the higher unlimited classes until reclassified lower. I figure even a well built, NA NB1 engine with driver is going to put the car around 10:1 lb:HP ratio.

Thoughts?

Okay.

It's a massively lightweight Miata with no windshield. Good luck getting it out of TTU, especially after you tell Greg that it's NB-powered.

Lulz of the day.

Thanks, that's why I was asking.

If you really wanted to do it, expect a tax of something in the 2.5:1+ point range (i.e. if you wanted to class it as a TTB car where the class minimum is 10.25, expect Greg to ask you to submit a dyno classing in the 13:1 range).

Thanks for the extra input.

I'm not too concerned with W2W racing (out of the budget thanks to the wife's travel demands), and I really like the idea of the Exocet as FUN (no window, exposed, lightweight) HPDE and possibly TT car.

So I was curious if there was any possible way it could be competitive. It wouldn't appear to be the case.

And if I say with the '90 because of the base model add-ons, I'd have to read back through the classing and TTE threads to see if I could just build it to one of those classes to scratch the competition itch.

if youre going to stay with a 90, swap in a 99 engine (or 01 if you want, slightly more work), dyno reclass, and itll be a killer TTE/D car. it teeter-totters between those classes pending what mods you do, but makes for a front runner--pending the driver mod.

I happen to think that a 01-swapped '90 chassis is quite a good PTE/TTE car ;)

Excellent. I'll do some more rules digging and read the few threads regarding it on here about what potential impact my chassis stiffening mods make and if the 6spd is worth the points.

You will hate the aero disadvantage in basically open wheel carwithout downforce. Light weight helps you in slower speeds. If tracks demand higher than 100 mph, stock Miata body may have advantage in straights. You will eat them in braking and acceleration from low speed corners. I had to downgrade my brakes to 1.6 to get them heated enough for track pads. (And have $20 used 13" slicks).
If you are in South-East (Road Atlanta, Roebling with mile long straights, forget exocet.

My local track, ~35 miles from my driveway, is Hallett. Very slow, tight course.

Even on my sport bike top speed going into the braking zone for 1 was only ~125.

I'll make it easy - neither are worth it.

Yeah, I came to that conclusion last night reading through the PTE/TTE Adventures and TTD Discussion thread.

Since I originally only envisioned my car as an HPDE car and was building it how I wanted, I've done some things that aren't ideal for TT classing:

FM Rails and Butterfly, Frog Arms, Sport Brakes, V8R Upper Front Control arms

But after doing some reading here over the last few months, I've realized I can still build a fun, fast HPDE car, that should still be fun to compete in TTE/TTD with.

Ugh, I also see my power steering delete is another point.

How do you figure? Its not a base model option.

From I. h. (NO Point Modifications)

12) Steering rack replacement or modification (without geometry change unless taking points for E.18). Rack ratio change is permitted. Change from BTM power steering to manual, and/or modification of the power steering pump requires the point assessment for engine pulley in C.10).


We pulled apart the rack and did the Flyin' Miata "proper depower" and removed the power steering pump and all associated lines.

Am I interpreting this incorrectly?

Yes. PS is not standard on any BTM model 90-97 Miata, ergo, no points assessed.

http://www.miata.net/faq/Miata90-97A3.pdf

Excellent, thanks for the clarification.

It's effectively a rack ratio change.

Another quick one as I'm trying to quickly bring myself up to speed on the points rules:

FM frame rails and butterfly brace +3
From Arms will also be an additional +3
V8R front upper control arms +4 (I'll definitely put stock back on with poly bushings)

Correct?

I'm willing to take the +2 on my sport brakes (although I'll switch them out for 949/TSE fronts and the new FM rear kit) to knock some weight, longer pad life and the increased feel from fixed position calipers.

+7 for the 949 Big Grip kit (which should also lose some weight over my current +7 poverty suspension)

And at some point add a Torsen.

I figure the car sits now with 90whp and 2350 with me in it. A proper 1.8 will be next winter's project.

Almost. You take +3 for all chassis stiffening parts, regardless of how many you do, so the FM rails/brace and Frog Arms are all under the same +3. V8R arms are +4.

FYI - FM beat us to the punch, but we've been developing a similar rear kit for several months now (4-pot Powerlites for the rear). The main difference will be that our kit will include bespoke 2-piece rear rotors and thus be around a pound lighter per side.

I'm happy to hear that. I really didn't want to give up the extra feel the Frog Arms gave the front end. If I also wanted to do the RB Control arm brace and FM Cannon brace, do those continue to fall under all "chassis stiffening" +3, or are they additional since they are on the subframes/suspensions?


I'm not quite ready to buy brakes yet, and I'd prefer to buy both from one place.......and if they will be a bit lighter.

The brakes should be good for what 8lbs up front and ~6 out back?

[QUOTE=z31maniac;1023918]I'm happy to hear that. I really didn't want to give up the extra feel the Frog Arms gave the front end. If I also wanted to do the RB Control arm brace and FM Cannon brace, do those continue to fall under all "chassis stiffening" +3, or are they additional since they are on the subframes/suspensions?[QUOTE]

The FM Cannon brace should be included in the chassis +3, but anything attaching to the suspension is going to likely add more points.

I'll be perfectly honest: No truly competitive PTE car takes points for any chassis bracing.

Depends on exactly what brake setup you're coming from. Should be closer to 8 out back, though. The original design goal was to shed as much weight as possible while maintaining bias similar to what you'd get out of an 11" Sport rotor setup (our kit is based on a 10" rotor). The only lighter setup would be something based on a 2-piston caliper, but the pad size reduction was a little too much for our comfort.

^THanks for all your input on this thread, it's greatly appreciated.

I figure the car will likely end up in TTD, I don't really want to pull the stiffening stuff back out of the car. It made a huge difference in feel for me (coming from track sport bikes).

The car currently sits on NB Sports brakes with centrics and Carbotechs'.

When do you suspect you will have the rear kit ready? I've also converted over to the Sport master cylinder/booster setup as well.

Will there be any sort of (mechanical) handbrake on this rear kit?

Wilwood does make a Powerlite caliper that can be adapted for a handbrake, but we're focusing on a handbrake-delete kit right now. The primary goal is to shave weight, and retaining a handbrake doesn't fit into that goal.

Balls. Was hoping for some mechanical backup while getting rid of some weight and single piston sliding pin ------ry.

probably shouldn't be using your handbrake at the track anyways. I am assuming this kit is probably aimed at the track only guys.

If you want your track car to be street legal most states require a emergency parking brake.

They also require no tampering with emissions systems, use of DOT approved seat belts and not removing the air bag, etc.

Haha, ok... good point, but in all of the inspections I've done they don't actually check any of those things. they DO check that the e-brake works (obviously this changes state-by-state)

I only bump this up as I ran across an older post of yours saying the lack of a mechanical ebrake a safety issue and how it saved you one time on track.

Have you changed your mind on this?

I just saw this post and it made me LOL because for 5.5 years, we drove around (summers only during track season) in a 1995 Infiniti G20 that had no cat, no airbags, no factory seat, but it did still have the DOT seat belts along with 6pt belts and we did leave the parking brake)

...Illinois is not only a non-inspection required state BUT if you have a 1995 or older car (OBD1) you never have to go for emissions test so we 'stunk out' people street driving a g20 (haha)

There are a lot of people who are willing to take that slight added risk in order to shave a bunch of weight out of the rear brakes. I'll run the 4-pot rears on Theseus, but Rover will keep stock calipers.

Fair enough. From what I'm reading from Keith and the power of the ebrake setup (at least on those Wilwood calipers) the ebrake function isn't particularly strong.

For SCCA legality, it gets you by. Our kit was set up for weight weenies from the start, so the assumption is that if you're paying the money to shave ~3lb per side on just the calipers and another 1.5lbs total on the rotors, the weight of the e-brake cables and the handle inside the car wasn't going to make the cut.

Wow, 9lbs of weight loss off the rear brakes is pretty damn impressive.

I thought I read in another thread you mentioned you were learning something with the rear kit that would translate to more weight savings on the front kit.......am I remembering that correctly? If so, when could we expect the improved front kit to come to market?

I'm completely digging the idea of pulling 25+ pounds out of the car with the improved brake setup and XIDAs I'll order this season vs the old Sport take/Vmaxx setup.

We're replacing Wilwood's hats with our own. Not necessarily reduced weight, but reduced cost.

What would that do for rotor availability? Will the wilwood rings fit your new hat or would it be a bespoke combination? I like the fm rear kit since it uses locally available oem rotors. Maybe not a huge deal for you US guys, but I like not having to wait for essential brake parts when I upgrade to the 11.75" fronts and powerlite 11" rears. (W/ or w/o handbrake).