flier129

iTrader: (7)

I've been talking to a friend of mine about TTD miata. I figure PTD pretains to TTD as well as far as classing goes, correct me if I'm wrong.

What do you think would be best route to go to be the most competitive in TTD? 01+ motor in an NA, a base 99-00, NB motor into NA with Rotrex and detuned, detuned Rotrex in a NB?

I believe a good "cookie cutter" setup would be very similar to 949's Crusher and Enzo. I don't know all the details on the cars and probable don't want to know everything right now because the price would probably scare me away, lol.

Keeping in mind that these are some parts I already have and trying to stay simple right now. Basically, here's what I've come up with so far:

94 R
ES bushings
Stock 5-spd
4.10 torsen
Xida CS
15x9s
225 NT01s
1.8 brakes, xp10/xp8, new rotors, SS lines, etc

99-00 head
01 block
MSM intake cam
square-top intake manifold
I/H/E, something light weight for the exhaust, RB or JR header, intake filter with a heat-shield, MAF delete for IAT.
MS2 with parrallel pnp harness
Shoot for 150+rwhp

welded in cage, nothing past the FW
seats, ideally with head restraints
a decent wheels
5-point harness
hard-top
front splitter(949 air-dam hopefully it'll get less points sometime soon?)
undecided on the rear wing
stripped down to 2400lbs wet, with me in it


I'm sure I'm missing something but I'd to hear other's opinions mostly. Main concerns being.....

Would the NB chasis be better than an NA?
Will my engine combo put out 150rwhp or more?
Should I go with VVT?
Are sport brakes that much better than standard 1.8s?
Would a 6-spd with a 4.3 be a better overall option or even a 3.9 and 6-spd?
Rear wing too much for a TTD/PTD miata?
Should I shoot for lower weight and less power?


TTD has being very appealing to me in the past year and half now. Especially since the local mid-south region has grown in the past year. It will be only a matter of time before MC hits the region too. PTD is way down the road but I know it only makes things more fun and exciting!

Efini~FC3S

iTrader: (4)

The guy who finished 2nd in PTD at the NASA Nationals has a de-tuned supercharged NA miata. I don't know much about his build other than I know it has a racing beat front fascia which he has to take air-dam points for. And I've heard it only makes 135-140whp, he is dyno reclassed.

I think it would be much cheaper to run a detuned rotrex than to copy what Emilio did for his PTD miata(s). I'm guessing his engine builds weren't cheap...

A couple comments about your proposed build, and TT/PT in general. My theory (we've won two PT championships in two years...) is that if you're going to take points for something, you had better be gettting the absolute most out of those points. You're proposing a 4.10 torsen, which means you have to take points for a LSD. If you want to be competitive and you're taking points for an LSD you had better have the best damn LSD money can buy. OS Giken at a minimum.

You would have to take points for sport brakes, I think. And if you're going to take +2 for brake calipers you had better have the biggest, lightest, best damn brakes you can get. No way +2 for sport brakes are worth it. Excuse my ignorance but do sport brakes use the same caliper and bracket has the standard 1.8s? Even if the caliper is the same as the standard 1.8s, you have to take the points if the caliper bracket is different.

You're planning on an airdam, splitter, and a rear wing? That's a whole lot of points. If you run just and airdam and a splitter you're probably not going to have very good aero balance. The guy who is nationally competitive in PTD has an air dam, and that's it. I don't think you can stay in "D" with all of those aero points. Emilio's cars take points for an airdam and a wing, I think.

Switching to the 6-speed is quite a few points, are those points better spent elsewhere?

Oh and 6 point harness or get out. You love your ***** right?

flier129

iTrader: (7)

Aero isn't the main concern right now. I figure I can get that sorted once I've gone thru the HPDE's and got my TT license. IMHO I don't think I would benefit from a rear wing anyways and like you said the balance would be off if I had a front splitter.

I thought one of Emilio's rental cars had a "junk-yard" motor that made 140-150rwhp n/a? I know the details of the two enduro car's engines weren't posted up everywhere. Either way, I figure the engine combo I posted could make 140rwhp at least.

I forgot you get hit with points on the LSD, even if it was standard on your package.

Wilwoods would be the answer to the best brake package I figure. Sport brakes do have different brackets and calipers :(

I think the 5-spd should be able to handle the n/a power, but it's bound to break at some point. The 6-spd might come in handy as far as gearing is concerned on some tracks, depending on the final drive too.

I also forgot about the nut-pincher, lol.

emilio700

iTrader: (3)

Try to find CoralDoc here or on m.net. He has an NA8 with NB1 motor and restricted C15-60 Rotrex. 9's, Hoosiers, no aero, 5 speed, Torsen. Pretty sure it's the fastest TTD car in his Florida region.

Our air dam will always be 6 pts. It was designed specifically for our SuperMiata W2W series so NASA pts consideration was not top priority. We took 3pts for OEM air dam and 4 pts for spoiler. All for drag reduction and maybe reduce lift a bit.

6 speed isn't worth points hit. If running TTD, a turbo will do the trick. Costs about the same as solid Rotrex set up if you can design, fabricate and tune yourself. If you want PnP, Rotrex ends up being cheaper and more reliable. N/A is also a valid choice and NASA doesn't really care either way, same whp limit. They now specify torque limits but those are generous, typically higher than whp cap. If VVT is an option, take it. It's free torque area that you will use, particularly considering you will likely run a 5 speed.

NA8 has to use 1.8 brakes if zero points. NB1/2 are on same line so can use NB2 base model Sport Brakes since they were standard after '02 (UD/BD). Light calipers/big rotors only needed for w2w and particularly enduro where pad swap speed is an issue. 1.8 brakes will get the job done for TTD.

You won't need a square top to make 150whp if you bump the compression and add a BP5A cam. On pure hp tracks, the bigger TTD cars will make your life hard but everywhere else a properly prepared and driven TTD NA8 can win.

flier129

iTrader: (7)

I've read Coraldoc's build thread on m.net, it's very interesting. I'm wanting to go for the simple route of n/a, I figure a rotrex will be just as reliable but more intial work. Either way, I'll want to talk to him, because he's doing something right in TTD, lol.

I suppose I'll be taking a hit for my OEM air-dam too :(

No 6-spd, opt for points for higher CR pistons and/or Rotrex? The prep work I would want to do for a turbo setup would be more expensive than a Rotrex, lol. But 160rwhp will be a lot easier on wear items than the standard 220-250 that gets used more often in this community.

My main concern with VVT is making it functional along with a MS or AEM. I have no experience with, something I would be diving head first into. But with enough help from this forum I'm confident I could figure it out. It's probably easier than I think it is too.

So I'll stick with the 1.8 brakes, simple enough. My friend is wanting a NB over a NA, he hasn't decided on a NB1 or NB2 yet. Either way the sport brakes won't hit him on points, so that's a plus.

There's a few tracks that come to mind that are HP tracks. I suppose higher CR pistons will put out better results than the square-top. And as you said NASA doesn't seem to car how you get the whp limit. Dyno reclass seems like the best option

ke0ki2k

I'm the guy Marcus was talking about - really hoping to get a competitive setup and avoid hoosiers (I know racing is expensive, but paying 280 a piece for tires really inflates the budget compared to relatively cheap 225 NT01's...RS3's would be even better but I dont know if they're capable of enough grip to be competitive). I was thinking of an 01-05 block AND head with VVT and a MS3 setup in hopes that we could detune at higher RPM and hold 160 whp over the entire usable range. I think the car would be pretty quick in class, and probably more reliable/cheaper than FI in the long run.

btw, I'm a miata noob so forgive any ignorant statements I may make in the future.

CoralDoc

I'm happy that my TTD build was brought up here since I think my car is fun and fast. At the end of 2011 it held all of the TTD track records in NASA FL. However, a VERY fast 350Z driver crushed the record at Homestead-Miami speedway by nearly 2 seconds! Both myself and another Miata driver could not get within 1.5 seconds of him even though we both broke the former track record.

There is already some very good advice above, particularly the bit about maximizing value for your points

If I were to do a TTD build right now, I'd opt for an NB chassis as a starting point. The two primary reasons for this are brakes and aero.

My car is a 1993 NA with a C15-30 Rotrex supercharged BP-4W engine. I'm dyno re-classed in TTD by Greg Greenbaum at 161 rwhp and 2,395 lbs minimum competitive weight (includes driver). I achieve the weight easily, even with a pretty complete interior and 6-point roll cage. Without ballast I have to end my sessions with at least a half tank of fuel to meet this weight. My other points are spent on XIDA-S suspension (3+2), RB front anti-sway bar (2), 4.3:1 Torsen LSD (3), and Hoosier 225/45/15 A6 tires (13-4 = 9) for a total of 19 points. This is the maximum allowed before bumping up a class. The main thing I'm leaving on the table is the LSD. The Torsen unit is way better than an open, but I agree with Efini~F3CS that the OS Giken is a better way to go (it's still on the list Emilio).

There are a couple details to consider here. If a car is dyno re-classed, the letter from Greg will spell out exactly what OEM parts you can use without taking points, and they must be from BTM (base-trim model). In other words, classed on points can use the update/backdate rule, but not cars that are dyno re-classed. For example, I asked for a dyno re-class for a 1999 Miata, Greg responded in his letter that "... all other modifications, including transmission and LSD, that are not standard items on a base trim '99 Mazda Miata must be assessed points." That means no Sport brakes since they come off a 2001+ BTM Miata.

The NB BTM Miata has better aero than an NA Miata.

The challenge is that the NB will weight more than my NA with the same power. Per Greg's letter, a dyno re-class for a 1999 with 161rwhp (same as my car) would have a minimum competitive weight of 2,420 lbs. Whether 25lbs more weight is worth the better aero and improved brakes (compared to the BTM 1.6 liter brakes on my car) is where the bench racing and conjecture can start.

ke0ki2k

That explains things a little more clearly, thanks! So would a 99' with an 01'-longblock swap need to be dyno re-classed? I know it says all engine swaps need to be reclassed but I wasn't sure in this case since the 99 and 01 are in the same base class. I was really hoping to avoid the re-class because I've been told that Greg has a habit of hamstringing TT miatas..

I also thought 350's were a TTC base class for some reason.. I actually own one right now, but I couldn't justify putting a chassis that costly onto a racetrack (if I wadded up an NB, I'm sure I could find another roller for cheap and transfer parts..wouldnt work like that if I put my Z into the wall).

CoralDoc

Any time you do an engine swap, it requires evaluation by the TT director (Greg Greenbaum). In most cases, it requires a dyno re-class. So, submit your proposal (in detail) and let us know the result.

350Zs are base-classed in TTC. This competitor received a dyno re-class allowing him to make 235 rwhp and weigh 3195 lbs with a TTD* (7 pts) base class. I'm a bit miffed because his adjusted W/P ratio is 14.39:1 (not far off the 14.25:1 minimum) and mine is 14.82:1. Miata drivers are supposed to make up improved straight line speed in the corners .

CoralDoc

Yep, +3 pts. I took mine off and have not noticed any bad effects.

My friend just added the VVT tuner box to his DIYPnP ECU and it works like a charm in his 1990 chassis with a 2001 engine.

flier129

iTrader: (7)

Thats encouraging, thanks for all the feedback.

Efini~FC3S

iTrader: (4)

Wait, what? How the eff do you get a dyno reclass, and get re-classed lower than the cars base class? Did he swap in a lower HP motor than was stock?

Never heard of this...

emilio700

iTrader: (3)

never read the rule book?

ke0ki2k

I figured that everyone in each class would use the points to be at or near the class limit P/W? Marcus and I were confused why you were so far off the 14.25 limit. I really don't like this dictatorial authority one guy has.. why not just let the rules decide classes? You have this many points... you can't exceed this power-to-weight ratio.. why the hell do we need this Greg character?

I guess i'll come up with a detailed description of my plans and see what he says.. if he tells me he's gonna reclass me in TTC with a 99' chassis, with the allowable points in modifications, and inside the 14.25 power/weight.. he may successfully scare off a customer. Is he pretty good about responding to these inquiries or am I going to get ignored?

Savington

iTrader: (31)

If you haven't done a motor swap in your 99, there is basically no reason to email Greg and tell him what your plans are. I'm sure you are capable of reading the rulebook, figuring out how many points your mods are worth, and seeing which class you end up in.

If you think you're going to somehow convince him to give you a classing that's close to the 14.25:1 limit, you're not going to like his answer. I will remind you that Miatas/MX-5s took over half of the available podium positions at the 25 Hours of Thunderhill, so it's not like our cars aren't competitive.

flier129

iTrader: (7)

"Get the frog, deal with the warts" saying has been thrown around on the NASA forums before. It's seems it's harder to build a purpose built car for the classes. I know I'll never be maxed out even in a class like TTD, but I try to get close!

I wouldn't email for a dyno reclass until after you've got the car prepped verbatim to the rules.

Efini~FC3S

iTrader: (4)

Cool story bro.

How many miatas were registered for the 25 Hour? What percentage of the field in each class were miatas and what percentage of each podium were miatas?

ke0ki2k

I was hoping to throw an 01' longblock into the 99' though, use the VVT to hold ~160 whp from ASAP to redline and stay just above the 14.25 p/w for most of the powerband.. so what you're saying is he'll likely re-class me to TTC if I flirt with that max power/weight like that with a updated engine swap?


well I can't request a dyno re-class without dyno results ;P

Joshua, when you said evaluation, did you mean submit the proposed build and see what he says about the swap... or build the car and then send him the dyno/weight/etc? I really just want to figure out what to build before I build it, know what I mean?

CoralDoc

Before spending all the effort in building the car, I would ask Greg what power you can make with the proposed engine swap. It's looking more and more that the 2001-2004 Miatas are going to be a good choice for TTE. They already come with improved torque and bigger brakes compared to the 1999-2000 NBs. Build the car from points, max out your W/P and go have some fun.

I'll also add that having a car that can dominate in PTx is very different than the max build for TTx, especially when you're building for an enduro as long as the 25hrs.

flier129

iTrader: (7)

+1 for a NB2 (01-05), after you add in the cost of a 01+ engine and take the time to swap it, you'll end up with less headache and almost the same money spent by getting a 01-05 over a 99-00. Especially if you find a inexpensive base trim with a decent amount of miles on it.

I wouldn't rule out Coraldoc's build either. You'd have the restrictor installed when your on the track, but pop that restrictor off, and you'd have an easy 200-220rwhp for the street . Used Rotrexes seem to be more and more common now too.

Are TTE NB2s using NT01s or the like? Do you guys think RS3s could be competitive at all?