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ST 5/6 (PT 5/6) Rules Proposal Thread--give your input here


Greg G.

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you know you have a problem when this is parallel to waiting until Christmas morning to open presents when you were 10.

 

You sir, win at posting.

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Oh boy. Limit of 14:1 with no tire size modifier points. Based off Greg's post in the TT forum that doesn't look good for me to stay in TT5...

 

Will wait to see the complete rule set once its posted but I'm not feeling optimistic about this...

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Have they been posted yet? When I go to the NASA "rules" page there's just the 2017 rule set for TT. I don't see anything for TT5...

 

Anyone have a direct link?

IT guy is driving to Thunderhill for the 25. He said that he should be able to post them within an hour (fingers crossed).

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Well, looks like there's no way my E36 M3 is going to fit into TT5 with this rule set. Not having the tire modifier plus having to take a modifier for a front splitter is a real kick in the teeth for me. The new average horsepower calculator doesn't help me any either, those 250 rpm increments hurt.

 

What's the reasoning for having to take modification points for a front splitter smaller than 4"? I figured if you weren't getting the OEM Aero points aero mods would be open like they are in TT1-4. Having to take -0.5 for my 3" front splitter certainly isn't helping.

 

There's no modifier for the type of R compound tires anymore either? So no + factor for running Nitto NT01 or Toyo RR's vs Hoosier R7's or BFG R1's?

 

Even if I add maximum ballast I still can't sneak in without running a restrictor plate and/or detuning to lose power.

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Well, looks like there's no way my E36 M3 is going to fit into TT5 with this rule set. Not having the tire modifier plus having to take a modifier for a front splitter is a real kick in the teeth for me. The new average horsepower calculator doesn't help me any either, those 250 rpm increments hurt.

 

What's the reasoning for having to take modification points for a front splitter smaller than 4"? I figured if you weren't getting the OEM Aero points aero mods would be open like they are in TT1-4. Having to take -0.5 for my 3" front splitter certainly isn't helping.

 

There's no modifier for the type of R compound tires anymore either? So no + factor for running Nitto NT01 or Toyo RR's vs Hoosier R7's or BFG R1's?

 

Even if I add maximum ballast I still can't sneak in without running a restrictor plate and/or detuning to lose power.

Then, I guess you have too many power mods for this class? Our proformas show that the E36 M3 is going to be very competitive in this class, even with some power mods, and the splitter, and a few others without detuning. Also, for most of the BMW Dyno graphs that we looked at, the updated Avg HP calculations still yielded a lower Avg HP reading than last year. Remember, we are combining two classes (eventually) into one, so some compromises have to be made. NASA executives felt that a more conservative approach that did not require PTD/TTD cars to have to find power or lose weight, but rather have higher HP PTC/TTC cars detune or add ballast, was the best approach as the starting point, especially given that on a national basis, the number of PTD/TTD cars is much greater than for PTC/TTC.

 

We have been saying from the start that Aero mods would be decreasing as we move down in classes. The choice was to entirely eliminate splitters, or give them an assessment. If your 3" splitter isn't worth 90 lbs (or 6 hp), then take it off. Future ST6 competitors can expect a further progression in the decrease in Aero modifications.

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Overall: I think the rules strike a great balance between fairness and simplicity. It's a solid foundation.

 

My car will be assessed either -10HP or +140 pounds because I have an SLA suspension. That's a pretty big hit, especially against say, a torquey BMW. Colin Chapman once said "any suspension will work well if you don't let it", and I believe that strut front suspension cars such as BMW, Porsche, and FRS/BRZ aren't REALLY at that much cornering disadvantage when we all have pretty dialed in setups. BMW E36M3 are hugely competitive and have a TON of lap records... they seem to be doing pretty well with struts up front. If you've got controlled roll and a good alignment, an E36 or BRZ will be utilizing it's tires similarly to an Miata or S2000. We also tend to forget that SLA cars lose contact patch and hence braking traction from front-end squat.

 

The dubiously realistic SLA assessment aside, my biggest heartburn is tire compound.

 

1. A 200TW Bridgestone RE-71R is faster than a 100TW Maxxis RC1, yet it receives a +0.3 modifier despite being a faster tire (that can run in rain, no less). A more realistic modifier would be "Non-R Compound with UTQG Treadwear rating 100 or greater +0.3". This would more reflect real-world performance and open the door to making long-lasting R-comps competitive. I thought this was one of the big goals...?

 

2. The +0.3 200TW tire modifier value is inadequate. Switching from a 200TW Bridgestone to a Hoosier R7 would only result in a 4HP loss or a +54 pound ballast in my car. I can only assume the Hoosier, even with the de-tune or ballast, would be 2-3 seconds quicker per lap minimum. This modifier should be something much closer to 1.0 (even THAT is probably insufficient), or we're just handing "wins" to people on Hoosiers, not earning wins with driving skill.

 

The ruleset is a nice piece, but I think the SLA and tire modifiers are off. I'll take the SLA hit grudgingly... but the tire modifier means that if I show up at all, it's just to show up and hand points to folks on Hoosiers. I have no interest in dropping $1200 on short-lived consumables.

 

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I have to agree that .7 for A arm is a bit extreme. I can understand .3 or .4, but A arms are definitely not worth 10 whp or 140 lb in performance when compared to a well setup bmw or brz on strut.

 

Giving more incentive to run 100 TW tires will also increase entries, at least for TT guys.

 

I thought idea of ST formula was to simplify the rules, and just mainly focus on p/w, tires and aero.

 

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Correct me if I'm wrong, but I think the FR-S/BRZ would also need to take the -0.7 A-arm/wishbone penalty as the rules specify front or rear. The twins have MacPherson struts up front, but are double wishbone in the rear, which I think means that we would have to take the -0.7 modifier as well.

 

The -0.7 for shaft diameter > 40mm also hits me pretty hard, but I understand the goal of trying to reduce spending on suspension.

 

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The advantage modifier for sedans is still there too. No difference between an E36 M3 coupe and sedan. Hard to see how an STi or Evo is at a disadvantage compared to a coupe...

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Contradiction on the bushing rules:

 

Does a LCA offset non metallic bushing for added camber result in adjustment to ptw or not? Suspension paragraph 3 and 5 specifically contradict.

 

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I wish having a splitter didn't take extra points.....no reason to run a wing (in my case) without a splitter. And just sayin', new dyno cert seems fair but even more complicated than. Anyone that comes to my dyno, I'm NOT doing your math for you!!!!!

 

How about considering the C6 Grand Sport Fascia for the BTM like the BMW? It has no advantage over the base fascia without the splitter, and it's the only fascia I have. I'm definitely going to a low power class next year, not sure which one though.

 

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Do e36 and later BMWs take the wishbone hit for their rear suspension? How do we differentiate between multi link and the rules definition of wishbone?

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Just a guess, but wishbone generally has three connection points, two on the body, one on the hub/carrier. BMW lower arm has one and one. Not really a wishbone.

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