ST4/TT4 Thread
 

So who is going to go this route? The 2017 rules are posted and seems like we could have a similar deal to STL if anyone takes advantage of it.

https://nasa-assets.s3.amazonaws.com...--10-31-16.pdf

FWD has quite a tax break at +.6 mod factor.

Todays PTE/PTD cars could become very fun by taking out your 200#s of ballast to make up for the extra Pwr:weight.

My my current car at 2210 can run at 192whp vs 141whp. While taking limitations off brakes, tire size up to 245 vs 205, and typical nice updates including NB subframe, spindles, and bumpsteer. Can do more than double adjustables and gear ratios are also open.

Fwd cars on 245s or smaller while under 2600# and over 2200# will have 1.1 additional factor on any rwd car. Enough for a free sequential/dog box, "A" tires, or 10-12whp.

Average hp is another piece of the puzzle.

Wow, I'm very surprised there wasn't a break for 225mm tires, hah.

This would be a very fun class to run, but a lot of development to get towards the pointy end of it.

2400lb NB @ 208rwhp ...... average. On 245 R7s, 15x10s, front air-dam & splitter, rear wing..... damn.

I only skimmed the rules twice, but I'm not seeing any way for a swapped miata with an aftermarket subframe to run ST4. Aftermarket subframes work in ST1-3 with the non-production mod factor, but that mod factor can't be used in ST4. Looks like unmodified OEM subframe is required.

Ecotech swap

Yes, no way for ST4. You have to follow the

This would allow any subframe that can bolt up from the OEM manufacture. No K-swaps unless you make it work with cutting the firewall and not touching the transmission tunnel. :/

So NB subframes in an NA are kosher, but the V8R subframe isn't. :(

Indeed... Though it might be difficult to get 205-210rwhp avg from an ecotec without cams/internal work, at least on a dynojet. I think there are gains to be made just by porting the head, which would really put the current ecotec swaps I've seen over 200rwhp(peak).

Even still, in ST with 245s and aero..... you'd probably be better off running 2550lbs+ @ 220rwhp avg.

You have a lot better shot at it than with a bp.

Relocation of suspension mounting points is not permitted in ST4.


That means NO NB subframe/spindles/bumpsteer in 4. Only in 3/2/1

Excerpts:

Under:
2200 lbs = -0.3
2600 lbs = -0.2
3000 lbs = -0.1

Over:
3300 lbs = +0.1
3400 lbs = +0.2
3500 lbs = +0.3
3600 lbs = +0.4
3750 lbs = +0.5
3900 lbs = +0.6

245 or smaller = +.7
250 to 275mm = +0.3

windshield removal = -.3
OEM aero = +.4
Sequential = -1
A7/R1S/C91 = -1


__________________________________________________ ___

Imagine this:

OEM-aero, Ecotec, NB

12:1 base
12.2:1 2201-2599lbs
11.5:1 245 or smaller
11.1:1 Oem aero


200whp/2225lbs

Wow.

on 15x10s and 245s :eek5:

EFR BP with flat 200hp from 4000rpm to 8000rpm?

I'd lean that way. More $$ but it would have better power area than a junkyard Ecotec.
The junkyard Ecotec swap could be "Spec ST4" thing, ultimate dirt cheap/go fast combo.

I also don't see 200 "average" hp from an ecotech being easy or cheap.

I dont know the exact calculations for average hp, but with really good boost control you can add/remove power in specific locations and even tune your setup per track.

Junkyard Ecotec would be far from optimized for ST4 but could still be quite competitive in most regions. Sort of like dyno classed, junkyard motored PTE NB1's. Butts kicked at East/West Champ but snagging wins/lap records regionally.

This was one of the many reasons I decided to bail on my K swap project and decided to go with the turbo BP instead.

I was just talking to Dan yesterday about how well a TSE turbo Supermiata S1 car crosses over to ST4.

Yea.

If we could get the splitter changed to 4", air dam up to 5deg and the wing raised to 8" above roofline - it WOULD be ans ST4 car!

put on some 245 Hoosiers and go!

Speaking of EFR's, they just showed a smaller version at SEMA called the 5951 that is smaller in every way, yet they claim it flows 95% of a 6258. It is 35mm shorter and 35% less interia.

We have decided to make a run at 2017 T25 in Vegas, E0 mapped from ST3.

:party:

Want to see this. I love thunderhill.

Was there any mention of the Mixed Flow Technology like on the 7163?

I don't think that's the intention from Greg. You can ask if you please, updating/back dating subframes and suspension pieces are legal. Bumpsteer is also legal.

Relocation in their minds for the rules is getting a torch out and welder. It does not say I cannot follow the update/backdate rule in ST4, I also don't consider bumpsteer relocation if your following this mind set.

I was able to read it both ways. It says you can swap subframes, but it also says that ST4 guys can't move pickup points. The NB subframe technically moves the points on an NA. I asked Greg, we'll see what he says.

I did too. I got the answer that I expected and wanted when I read the rules.

As long as it's factory bolt on its good for ST4.

He also states an answer supporting this on the NASA Forums.

There was also a clause somewhere that you can backdate/update oem components without a penalty.

https://www.miataturbo.net/attachmen...ine=1423402060

http://myimages.uk-plc.net/c314612/P...Dry%20Sump.jpg

Dry Sump Kits - Pace Products

Maybe? @Kmiata

Looks like it might just clear the rack.

I looked at the Pace kit in initially, but I don't think it will clear. Clearance over the rack would be close, but I also don't think there is any room for the big external pump.

So did Greg respond to anyone about if we can use a tubular subframe with all OEM pickup points? I know at least a few customers have asked, so not sure if that has swayed the decision.

edit: nevermind, I checked my emails and I had confirmed that it was a no-go earlier this fall.

I haven't emailed Greg, but my understand is it's not allowed. This would fall under the +0.4 non-production adjustment in TT1-TT3. non-production is not allowed for TT4, and even if it was, isn't worth the penalty unless you really go all out with a tube frame. I know of one LSx Miata that runs TT and has to take non-production for not having the factory unmodified subframes.

And back from the dead...

Toyo's look hot with the new 2022 rules but it seems like it's going to be right at the limit or just beyond the reach of the K24Z3 crowd...

I don't know if I can get my comp weight much lower than 2250, and at that weight with 245 Toyo RR, aero, and even no cable throttle credit I'd still have a max of 225whp AVG. With most guys making 205 to 210whp on pump gas, I'm hoping e85 is worth another 10whp, and the underdrive ATi super damper, exhaust collector porting, and velocity stack intake, together hopefully another 5whp? So best case scenario I'll be able to do 225whp all in and no ballast? Not really ideal, I'd prefer to be running heavier. Only thing I can think of left to do is higher compression pistons, punch the block out and send the head out for CNC porting. Other than that what else is left?

Switching to Hoosier R7 is a whopping 31whp difference at that weight...

12.0 base P/W
2250lbs -0.2 penalty
Toyo RR +1.6 credit
245mm Tire Width +0.6 credit

After mod factor it's 10.0 P/W now.

Still worth it! :rofl:

If I ever run ST4/TT4 I'll just be slightly underpowered, but still plan to run R7s. Maybe as time goes on the k24z3 will get some more support to make a tad more power easily?

I finally reviewed the new rules.

I'm a bit surprised that the R7 will be required at the Championships.
NorCal doesn't usually run at Laguna Seca and has no events there this year. I'm not sure if SoCal will. Someone I spoke with at the 25 made the note that NASA was essentially encouraging racers to join another race group in order to get track time there before the Championships.

With the R7 required for the Championships and making such a big impact on power limits, no wonder they've gone crazy with the rules around ECU maps and switching.

There was a thread on a NASA forum about the new rules in which they said that the current ST4/TT4 competitors are mostly pretty happy with Hoosier and want to stick with it. They were suggesting that in 2023 it may become a Hoosier spec tire class, and that this was the reason for the special rule at the championship event.

--Ian

Very interesting. Shows how little I know about actual ST4 competition, as opposed to just what I imagine in my nutty little world.

So basically the strategy would be - run +18 HP on something like an RS4 until I'm within shouting distance of contingency Hoosiers, then give up those horses and swap to Hoosiers?

Purple crack indeed...

Correction - for 2022 I could run the non-Hoosiers, but in 2023 I'll need to be robbing banks to pay for tires...

I really wish the MK60 was allowed in ST5. I really don't want to give it up, but maybe that's where I'll be in '23.

Whoever said they like the Hoosiers for ST4 has to be winning them. Toyo now has better contingency, better prices and better longevity. Everyone at a regional level is going to be running that. Would be dumb to turn it into a spec Hoosier class.

Here's the thread: https://community.drivenasa.com/topi...oday/#comments

--Ian

Y’all are way out of the loop. Fast and front running ST4 cars are $80-125k builds. It’s essentially a spec E46M3 class. It’s fast and expensive and Hoosiers are absolutely the norm. Hoosiers are the norm in ST5 too btw, and they will still be at the front in 2022.

spoken as a former ST1-4 series director and contestant in 5 different regions over the last 5 years.

I don't think I'm that far out of the loop. Spec Hoosier is dumb any way you put it and will only serve to decrease participation. I'm not against spec tires when implemented in a decent fashion but they literally picked one of the most expensive tires, with the shortest lifespans, with a contingency program that only serves to reduce tire costs of the top one or two cars by 50% if they are lucky since it's now a BOGO contingency. In 245/40r15 the Toyo RR is exactly 300 dollars cheaper per set than Hoosier R7 and if you're getting 12 decent heat cycles instead of 8 decent heat cycles, tire costs on RR's are going to be about 50% of what you would need to be running Hoosiers. 1800 dollars per 24 decent heat cycles (two sets) on RR and 3600 dollars per 24 decent heat cycles (three sets) on R7.

I've seen the 80-125k builds and they're nuts but honestly they are outliers in the vast majority of regional participants. I consider my build over the top and hopefully competitive on a national level but it's still not even half the budget of some of these E46M3 dudes.

After reading the thread and seeing that they want to go to Hoosiers only for 2023 that honestly pisses me off, because it makes it that much harder to try to entice new drivers into race group. If they now have to buy Hoosiers just to try it after they spend a boat load of cash for things like a roll cage, HnR, fire system, it's going to stop people from trying. They might say that "oh serious racers know that the Hoosier game is reality" but the vast majority of "serious racers" started off as someone who dipped their toe in before they just jump into the deep end.

I don't like it.

And a ton of people at the regional level are going to be running Toyos. With the gaps in skill at regional events too the 1.6 modifier is going to be enough to give a better driver a fighting chance at beating Hoosier cars that may not be driven at quite the same level now as well and will start to change people's perception of how competitive you can be on non-hoosier offerings.

It's not BOGO, you're allowed to claim contingency more than once from the same invoice.


I'd be surprised if they make ST4/TT4 into spec tire across the board and not just nationals. A front running build on a 1.6 modifier tire could certainly be REAL hard to pass in ST4. I think Hoosier will still be king in TT4(and TT5).

The language seems very clear to me... might want to read it again. Trust me I used to turn in one invoice for the year and then stack an entire spare bedroom full of free tires but that's not how it works ever since the start of 2021.

https://prizes.drivenasa.com/hoosier...gency-program/

• A copy of a paid invoice is required and must accompany all redemption forms submitted. The maximum number of contingency tires that can be claimed is equivalent to the quantity of tires listed on a paid invoice, e.g. buy a set of four (4) Hoosier Tires and claim a maximum of four (4) contingency tires for that invoice. The invoice must be dated within 90 days prior to the event. Contingency awarded tires or random draw tires (i.e. no charge tires) will not be eligible for contingency.

I've received contingency more than once off the same invoice in 2021. The invoice just needs to be within ~90 days of the claim.

This. Exactly.

I'm this guy. I spent most of this year upgrading our car to be ST4 legal, even though I intend to run TT4 and not do W2W. The turbo is going on this summer, and I was planning to start hitting NASA events in fall 2022. I'm never going to be a serious front runner in points because I don't have the budget to run a full calendar of events. But I'll be out there filling in the field when I can, cause I'm just there to work on my car, work on my driving, and have fun. The competition is just an extra motivator for me to do well at an individual event. If they make TT4 a spec Hoosier class, I'm out, for all the reasons Aaron noted above. Toyo RR would make way more sense as a Spec tire... 'cause isn't the whole point of a Spec tire to level competition and keep costs down?

With a turbo BP, there's no way I'm running TT5/6, so if I'm out of TT4, I'm out of NASA. NASAs race program is my only reason for stepping over from the other HPDE events I've been running for the last 7 years. If I'm not running TT, no reason to pay for additional memberships and put up with all the startup hassle just to run HPDE at events that are more crowded than where I'm currently running.

Lurker in this thread as we're no longer in NASA ST/TT..

I wonder why NASA rules still favor Hoosier so strongly. Toyo can afford to not have any business from NASA I'm guessing. They can sell millions of all seasons to SUV owners just fine. OTOH Hoosiers business model for DOT radials is almost entirely dependent on NASA and SCCA road racing and to a lesser degree, VARA, BMWCCA, etc. SCCA street class went to 200tw a few years back so that market for A7's vanished. Hoosier is more vulnerable to a drop in demand for DOT radials if NASA rules were changed to favor Toyo. So I wonder what Hoosier pays NASA compared to what Toyo pays. Toyo is a title sponsor yet the rules still favor Hoosiers. Odd that.

/thread drift

I think a better way to express what I'm thinking is that though Hoosiers may be the de-facto spec tire for ST4 front-runners, having a mod factor that can allow me, as a novice racer, to run a far more affordable tire in the class, makes the class available for me to enter. As a novice, I won't be a front-runner, but if the mod factor is at all accurate, it might allow me to be competitive with some part of the Hoosier-running pack.

Basically - I don't want to spend money like a national-caliber driver in order to enter the class at all. Isn't that part of the spirit of amateur racing?

I honestly think they wrote "R7s only for ST4/TT4" into 2022 Nationals solely because of community support of it(on NASA's forum). ST1-3 and TT1-3 aren't required to run Hoosiers at nationals, which is the main reason why I think it was written in from client feedback.

I hope they don't make the Hoosier a spec tire nationally for ST4/TT4. Like y'all have said, running on other tires is key to bring in the numbers into ST/TT. I fully expect regional races to see Hoosiers vs Toyo/Maxxis/super200s, especially W2W.

NASA's rules certainly don't favor Hoosiers in 2022 and they have been changing the rules to help push out Hoosiers for years now.

If NASA decides the shove through a spec R7 for ST4 across the whole organization, it's going to blow up the WERC enduros because most of the E1 teams were not running Hoosiers. That's a complete rethink for a lot of those teams for how their cars are built, and how they approach a 6 hour race. The WERC director is going to have an upheaval --and a significantly different rule book-- if they need to let people run RRs or 200TW on cars built to the "old" ST4 rules. I don't think it would be a positive change for the enduro program if they force all of E1 into that box.

I'd suggest we all start posting in that thread...


https://community.drivenasa.com/topi...oday/#comments

But how many ST/TT1-3 cars aren't running Hoosiers? I don't know of any competitive guys in Great Lakes region that weren't on Hoho's the last few years.