NASA ST6/TT6
 

New for 2019. No more Performance Touring(PTE/D/F)

Provisional rules posted.

https://nasa-assets.s3.amazonaws.com...1--7-31-18.pdf


Keys off the top:

17:1 P:W
A arm penalty moved up to -.8:1 P:W.
No more Sedan/Hatch credit. (+.2)
226mm section width breakpoint moved to 2450lbs.
Splitter banned.
Spoiler/Wing allowed, but big penalty -1.0:1 P:W

Engine, Brake and Transmission update/backdate still free.

Seems a typical points build NB or TTE* reclass is going to slot right in with minimal changes, which should be expected. Now to steal some wind from the sails of the TT/ST5 crowd and do some poverty class recruiting.

Yeah, looks like you can still do a pretty cheap PTE style build. NB2s are finally back on par with everything else. Now time to start pouring over all the random 0 modifier bullshit lurking in there.

2450+lbs
-.3 <2550lb
-.8 A-Arms
+.4 BTM aero
205 R7s on a 15x9, although there may be a better non-hoosier option since that is fairly narrow now.

~138 avg whp. NB2 motor with bolt ons should do it. Very happy about that since that is in the range of extremely cheap power.

Comp weight less than:
2850 -.1
2650 -.2
2550 -.3
2450 -.4
2250 -.5
2150 -.6

A-arms -.7
BBK -.2
Spoiler/Wing -1.0
Splitter banned.
Floor drop penalized.

Update/backdate means Sport brakes are free.
NB engine swaps get a free 6spd trans (BP4W and BP6D)

At 2451lbs you get acces to 257mm (225/45/15 R7)



Most PTE cars will take -.4 for weight and -.8 for Aarms. Effective P:W goes to 18.2:1.
That's easy peasy to hit with no "points" for headers, squaretops, etc.

Don't you get .4 back for BTM aero?

This confuses me, ST5 specifically talks about air dams. ST6 has this. But attaching a sheet of ABS to OEM bumper skin would be 'modified BTM front facia,' no? What is NASA trying to allow here? Aftermarket bumper skins? Does someone need to produce a SPM style air dam for us to run in ST6?

Mazda Miata (’90-’05): The driver’s side floor pan may be modified to accommodate larger/taller drivers. All modification shall be contained between the transmission tunnel, driver’s side rocker, rear bulkhead and no more than 24” forward of rear bulkhead. The modification shall not extend below the factory floor stiffener/frame rail. The steel used in the modification shall be no thinner than .060”. All modifications shall be welded in place. This modification shall serve no other purpose other than seating position. A -0.2 Modification Factor will be assessed for this modification.

With no spoiler/wing to balance it? Nah (imo). I almost wonder if ST6 BTM aero will be adjusted, b/c it doesn't make sense to apply a massive -1.0 hit to spoiler/wing, but give .4 back for BTM aero when the only thing in between is an air dam. Unless I'm missing something. Seems for ST6 BTM aero should just be the way it is and anything beyond that takes a modifier, but, eh.

The ST6 allowable front bumper aero rules read a bit weird. It seems like a front air dam isn’t allowed? Seems odd because there wouldn’t be much reason to not go BTM aero.

Is that for things like the S2000 CR? Not that it's a legal ST6 car.

I do find it entertaining that they specifically called out the NC miata is banned from TT6 with the whole <168hp rule.

A couple tid bits I found:

6) Non-OEM metallic and/or spherical design replacement suspension bushing modifications on control/camber/toe arms/links, panhard rods, watts links, and torque arms shall be assessed a Modification Factor which is in addition to and additive to #4 & #5 above. (Includes replaced, modified, adjustable, or altered control arm ball joints for roll-center correction or camber/caster adjustment. Note: ball joint may be welded to the spindle for added strength).
Points for ELBJ

1) Anti-lock braking systems (ABS) may only be OEM or offered specifically for the car model (that generation, any trim model) as a factory option. No OEM systems offered for a different car model or aftermarket systems are permitted.
Looks like I'll be retrofitting ABS.

Seems like there is no point taking -1.0 for a rear wing, since you can't balance it out with a splitter.

Minus the confusing BTM aero, I like the idea that in 1 night and a different tune I can bounce between ST5 and 6.

This is going to make for some bigger run groups in the SE/Florida regions.

The BTM aero language specifically refers to cars like the S2000 CR and/or Nismo 370Z, if I recall correctly. That same language was in the PT rulebook IIRC.

One thing I discussed with my buddy today is hood vents, fender vents (for cooling purposes), flat floor, and diffuser are legal.
The fender vents will be difficult to weasel around to fit the definition of "cooling vents."
The diffusor should be legal, and can be optimized since:
6b) Removal of the floor section of the rear hatch/trunk space and either replacement with a sheet metal cover or placement of a fuel cell is permitted without an additional Modification Factor.
4) Cutting/removal of the rear bumper cover/fascia where it does not cover the rear frame/bumper cross beam.
We both think the aero mods will be worth the 0.4 penalty, assuming you can manage to vent the fenders. This would act as drag reduction and downforce generation (albeit limited). So it will also improve your top speed.

Also the wording of the roll cage rules allows significant chassis stiffening:
CCR 15.6—Roll cages may be built to provide an unlimited amount of chassis stiffening. Any number of cage mounting points above the minimum required can be used. Any number of additional tubes, including those penetrating the firewall are permitted. (note: any tube(s) penetrating the firewall/front bulkhead shall be assessed a Modification Factor.) Tube-frame chassis conversion (partial or complete) is not permitted. If a vehicle cannot be driven safely, at full speed, with any of the added tubes removed, it is considered a tube-frame chassis conversion.
We're thinking you tie the cage into the firewall with two plates, then you have a triangulated strut tower brace that happens to bolt to said plates. No tubes protruding... no -0.2 penalty.

Does anyone actually have any idea what you can do with the front end aero allowance?

Not even a little bit, other than (for Miatas) something like R-Package or GV lip, although I'm not even sure that's allowed. The fact that the air dam is specifically called out for ST5 definitely muddies the water.

I think the aero idea is a bit of stretch, especially in a class where a spoiler/wing is so severely penalized. Whereas ST1-4 is unlimited unless stated otherwise, ST5-6 appear to be more along the lines of if it doesn't say you can, you can't. As with PT the flat bottom/belly pan forward of front axle center line is called out, so if full flat bottoms were allowed with a modifier I'd expect wording saying so. Same goes for diffuser. I don't read the bumper cut or removal/replacement of trunk floor as allowing a diffuser or flat bottom. I could certainly be wrong.

I am surprisingly pleased with this rule-set! I can add a few more horse-powerz and a 6spd. I also get to keep my current suspension and only have to add ~20lbs of ballast to insure I'm 2451lbs + consistently.

I'm on the fence about adding a MS to replace my reflashed stock ECU. Purely from a "budget" stand point, not from a "what mod should I do next". I know it's better to have it so I can likely adjust/improve the curve, but if I can get away with not spending much money and still be competitive in 6, that's cool with me.

You already make more power than I do with an MS3, sooo unless you plan on running e85, bigger injectors, or have a specific reason to run MS not sure I could justify it either. Think I'm gonna stick with the power I got, drop nearly 100lbs, and run RR's since they finally got a good contingency. Not that I've collected any contingency anyways, so really just trying to cut down tire costs and get some more reasonably quick HC's.

NASA forums question about ST6 aero got a non-answer. Sigh.

Aero mods are a sure case of "it doesn't say you can, therefore you can't"
6.1.5. says: "aerodynamic parts/devices/aides shall be limited in ST6 to the following: " and never mentions diffuser or flat floor. Expect to get bumped to ST3 with a diffuser or floor.

I read that as you either leave the front bumper 100% OEM BTM to earn the BTM credit, or take the .4 penalty which allows:
a. Rpkg/LE/SE/Sport/LS tupperware/lips.
b. Aftermarket fiberglass bumpers that don't have canard-y shaped bits.
c. flat front plastic aridams we've been running for a decade.

In 6, we're not allowed splitters, so your front bumper has to not earn a 'splitter' protest like the GV lips proved to.

I think some of the confusion is that the air dam isn't mentioned in ST6 aero rules, then is specifically called out in ST5. So seems only A and B apply from above. Guess it doesn't really matter because I can't imagine throwing away +.4 for an air dam.

I think the intention is to keep 6 as OEM aero as possible. But allowing "modifications" to BTM bumpers, non-btm bumpers or complete bumper replacement would seem to allow an added lip or airdam.
The odd part to me is the rule in 5 about extending the airdam beyond/below the bumper edges. That might not be allowed in 6, but needs cleared up.

Either way, a 'heavy' BTM NB2 looks mighty strong in 6.

Ahhh, I think that's it. I didn't read the ST5 air dam rule well enough.

Agreed. I would love to make more power and run on the heavier side. Only track it might not be ideal for me is Cresson 1.7, but MSRH, CoTA, NOLA all have long straights were mo' power is ideal. VVT is definitely gonna be strong.

My long con finally paying off. Already got a 6 speed lined up. Now to figure out rear end and how much to spend making the motor rev.

ST6 rules make me thing we could run an air dam that kicks out 2" in all directions. I'm pretty positive that Greg does not actually want that though.

205s on 8" wheels tuck nicely behind an OEM NB2 bumper. No airdam means you get half your A-arm penalty back.

With a diy rules-max undertray and hood vents, it would be pretty slick still.

Oh, didn't even think about the NB2 front bumper. My NA crutch gets even worse then, BUT at least I get bump steer shims /sarcasm

Would you ever want to be on 205s though? I'm not seeing why being lighter is better, especially now with the tiered tire sizes.

If you can't make the power to 'fill out' a 225 R7 or 245 RC1 build, yes.

Assuming BTM aero and 17.8/9:1 adjusted:
2250lbs gets 125avg whp
2450lbs gets 137avg whp

NASA is doing a good thing by widening the gap from 226mm to 257mm, IMO. The 2018 rules have a sweet spot at 2400lbs opening the 257mm allowance. There is less of a bonus incentive now to run heavy, other than the old "more raw power at the same ratio" race-ability vs other heavy ST6 cars. For a TT car, I don't see much reason to ballast up heavier than an old TTE/PTE car.

Comp weight pound per tire millimeter:
2250lbs on 205s = 2.74. Current setup
2400lbs on 225s = 2.66. 2018 rule, going away.
2450lbs on 225s = 2.72. 2019 rule.

Also, it gets pretty hard to push a 225 R7 or 245 RC1 down a straightaway with only 140 peak whp.
Also, also, consumable costs go down with less weight and fun-to-drive factor goes up.

There is an opening for a big power car to fit both 5 and 6 with the addition/subtraction of the max 250lbs of ballast though. Which could be useful depending on regional car counts.

So does an NB have an advantage over NA in ST6?

Better (BTM) aero and can fit more wheel/tire?

Some initial testing (heresay) seems to indicate that at 135ish whp that a 205 on a 15x9 is faster than a 225. For an NB, what about a 225 R7 on a 15x10? (Are the 225 R7s that much wider than the 205s?) I suppose it's likely to be track dependent. For places like CPM, AMP or Barber I wouldn't be surprised if more tire was faster. Daytona or VIR? Yea, probably the "skinny" tire.

For my car I may lean toward a combo ST5 / ST6 upgrade. I'm already pretty close to the power limit in ST6, would only need to ballast up 30ish pounds. Add sway bars, change spring rates? I have a built VVT motor that just needs the head re-freshed. Could run a 93 octane turned down tune in ST6, pull ballast, add wang and front dam/splitter, and have a high power e85 tune for ST5. Depending on ballast and aero bits, the swap could be as easy as 45 minutes work? As Dan alluded, this may be the way to go here in the SE to be able to swap between the two classes depending on car turnouts.

For a points build NB1, what are cheap engine reliability/durability/performance upgrades that I can do now that I couldn't before? Flat-top? Skunk2 TB?

NB have the advantage of donor parts coming with the car that need added to an NA: 6spd is free if attached to an NB engine, Sport brakes and BP4W/BP6D come with the right base car. Plus the better NB suspension geometry.
BTM aero advantage is small, but matters. Mainly NB2 only as the lower bumper corners cover a bit more tire.

Ultimately, its geo and BTM aero.

Tire wise, I don't see 225 R7s being faster than 205R7s on an ST6 Miata. The .1 P:W credit is smaller than the dyno cushion we should be leaving. The extra 200lbs of ballast is offset by 11 whp, which is big, but you're still working with ~140whp max. Consider that you need to warm that tire up on an outlap too, and you're still going to get walked on the starts by a car that actually gets to run at 17:1 P:W.

Why only 140whp peak? Wouldn't a non massaged curve put you in the 150+range?

e: looked at an old dyno run and there is only a 3hp difference between my max and average.

Yeah, I agree with your edit there. My peak and avg are ~4hp from each other. I would guessimate that delta would increase a tad as you add power or potentially RPM.


Luke and I were discussing gearing options.... 6spd/4.3 vs 5spd/4.77.
Upside of 6spd/4.3 is you don't have to change a final-drive and the gears are set a tad closer, but is that tad closer really worth it? Downside, ~$600 transmission replacements AND I'd have to buy another MR shifter.
Upside of 5spd/4.77 $100 replacements, already have MR shifter, and gota rebuilt diff anyways. Downside, sourcing 4.77 and installing it. I might run out of gear at Daytona(?)

For the sake of discussion here, price aside, what's the best gearing option...... depends on the track?

I was thinking about going 6spd/4.1 purely b/c my car still see's street duty, but I am curious how high into 5th I'm going to get on CoTA's back straight with 4.77's. With ST5 power/aero it might become an issue. At current 136whp and 7200rpm it shouldn't be an issue at all. As for peak vs avg I don't have a print out of rpm/hp, but eyeballing it mine is about a 6whp spread using 7200rpm, but drops to 3-4whp if using 7000rpm and fewer data points. That's probably just poor tuning though, my BP4W seems to be a bit more peaky than most so think I'm missing some power below 6000rpm.

I could definitely see running out of gear at Daytona on a 5spd/4.77. Our Chump Car on the NA BP would just run out of gear at the end of the straight at Sebring (~125mph). We were making a 120-130whp.

You will run out of gear at Daytona. I almost run out of gear at VIR with a 5-speed, 4.77 and 7400rpm limit @ 133 peak HP. The 4.77 build really needs the 8k redline.

Between those two, the 6sp/4.30s are faster, but only because you didn't go short enough on the R&P with the 5sp. Once you have the 5sp geared to use 3-4-5, the RPM drops between gears between the two are within 100rpm (the 5sp actually has a small advantage on the 4-5 shift over the 6sp). The 6sp/4.30 goes much slower in gear than the 5sp/4.77 does, though, so you end up with higher average RPM and more power to the ground in the real world. In order to make up that difference, you would need to do 5.38:1 gears combined with the 5-speed.

Approximately equivalent speeds in 3rd/4th/5th:

6sp/3.303 vs 5sp/4.10
6sp/3.636 vs 5sp/4.44
6sp/3.909 vs 5sp/4.78
6sp/4.10 vs 5sp/5.13
6sp/4.30 vs 5sp/5.38

Less speed in each gear means RPMs will be higher on average, and that's important because...

...generally, the best gearing option is the one that maximizes RPM at all times. In general, if you maximize RPM, you maximize horsepower. If you want more RPM at the same speed, you need to go shorter. Therefore, generally, the best gearing option for a given track is the shortest possible option that still allows you to hit max speed on the longest straightaway.

The caveat to "generally" is that if you have a specific important corner on a track, or if you have a track with lots of slow-speed corners and then one very long straight, you may be better off going slightly longer on the R&P and sacrificing horsepower in order to eliminate some awkward shifts. The "right" way to solve this caveat would be to add RPM capability instead, though.

You can do a lot of analysis of the track, GPS speeds, etc. This is what pro teams do. Or, you can simply set the gearing so that you reach max RPM in the tallest gear at the very end of the longest straightaway, and you'll probably get 95% of the way there.

Corollary to that: The big benefit of the 6sp is the ability to achieve max speed without needlessly lengthening the R&P. Packing 4 ratios into the space of 3 means that the average RPMs are higher, and when RPMs are higher, horsepower is higher.

I bang my head against my desk every time someone says they "like long gear ratios" for this reason.

So in theory a 6-speed with the 4.77 and a high enough rev limit to not run out of gear in 6th could be good? Assuming you don't end up with super shitty shift points all over the place.

Yes.

I don't recall. I think we were on 225 Hankook RS3's on 15x8's that time with a stock ECU. Drafting was required to max out the speed just before the brake zone (so perfect gearing?).

Telemetry is now allowed in the ST rule book. That was something I wanted to play with, but couldn't do under PT rules.

We ran that combo at 2014 Runoffs Laguna Seca in our STL car, NB1 with B6. Gearing was spot on for that relatively slow track.

:dealwithit:

:likecat:

Miata 226 vs 257 @ 17:1
 

So is the consensus on the front aero that any small splitter is disallowed? I know that you get 4" in TT5, but if nothing's allowed in TT6 then why does the line, "functions as an airfoil ... and extends 2" or more past the outline of the immediate surrounding fascia is prohibited" even appear if all splitters are forbidden? I first read that as differentiating the larger TT5 splitter from a smaller TT6 one. It also seems odd to be allowing things molded in to "a replaced front fascia ... during the original manufacturing process" but not allowing the same piece to be built.

I read it as nothing is allowed except items called out in the previous section (cooling and whatnot) and appendix b. With the -1.0 modifier to rear aero the rules are clearly pushing zero aero. The iii section is calling out OEM front ends like the s2k CR, which was nerfed on the old rule set too.

Uuuggggghhhhh

https://community.drivenasa.com/topi...in=1#replyForm

I just don't see the logic behind this 18:1 proposal. How does this increase participation for 6? Not to mention the displacement rule which excludes SE30 and S944. ST6/TT6 is fucked with this rule-set.

The cost of SpecE46 is looking like less of an issue every day.

So the short story for me is;

my low powered TTE car that weights 2415 could lose weight pending my dyno results?
I/h/e/timing wheel

I dunno, doesn't seem TOO bad. I would have to add 30lbs of ballast to hit class limit, but that's after (mostly) optimizing for a class that's about to no longer exist. My ole BP05's meager 125whp would have been pretty perfect for running a little bit lighter setup. A heavy VVT 6 speed with mild power is probably going to wreck shop in this class though.

2460 / ~132avg (TTE* 136 peak) = 18.6
-.7 A-Arm = 17.9
-.3 Weight = 17.6
+.4 BTM Aero = 18

I think the 18:1 limit also puts to rest that thread of guys complaining about how their NC/FT86/RX8 street cars are too heavy / underpowered for TT5 and should be moved to TT6 because they don't want to remove their passenger seats or throw cams at their motor.

Except NCs are specifically banned from ST6.

That's my point. They have less of a leg to stand on now that the limit is 18:1 vs 17:1. Their argument at 17:1 was that they fit pretty damn well into TT6 and they weren't wrong. At 18:1 an NC would have to be bone stock I/H/E, so they could still fit without the exclusive ban, but it'd be a stretch.

There are 3 really loud folks who didn't want to change anything on their car go from E to 6. Everybody else now gets to go slower.

I actually like these three official changes:
The weight break for 226mm versus 257mm NSW will remain 2400 lbs.
The A-Arm Mod Factor assessment will remain at -0.7
100 TW Tire Mod Factor assessment will be increased to +0.5

Moving the class to 18:1 actually makes dyno reclass cars easier to fit into 6 without buying parts. Those reclasses were 18.5-17.5(for a 16.5 class). Now, they're potentially spot on pending some ballast here and there with no other changes.

Ahha, I misread.

My writing is typically as clear as mud, no worries :p

Yeah I'm not quite understanding the logic behind that one.

I read those rules, but was too angered by the exclusion and going slower bit to digest them.





I'm with you guys on this. What.The.Fuck?!

I've posted a reply on the NASA forum thread. I'd like to get as many people as possible to post on this thread with their feedback for ST6/TT6 for 2019.

From my perspective, I can suck it up on the higher ratio, but that displacement rule could really really hurt the class.