2023 Proposed ST Rules Revisions--Comment Period through 11-20-22

[flier129]

What's the main rationale of the ST/TT5 base ratio change? 

For the a-arm modifiers would it not make sense to have separate modifiers for each axle. Say +0.250 per axle?

[stewlemm]

I know there were talks of the drop floor rule being revised. I have an st6 Miata and have a drop floor only to fit the seat. I am 5’6 and don’t need a drop floor. When the car was built this was done. Any help on this would be great because I am taking an unnecessary penalty here. 

[Captain Awesome]

I'm with everyone else on the 305 being a bad idea due to lack of available tires. 

but can we also get rid of this rule?
ST4 only (excludes TT4)--The Hoosier R7 and A7 will be the Specified and only permitted tires at the 2022 NASA Championships.

it doesn't allow an ST4 competitor to build their car to the extend of the rules if they have hopes of going to nationals.

[Phloozy]

Can someone help my naive self. For the throttle body rule, what advantage does someone with an electronic throttle body have? I run a BMW 128 with an electronic throttle body so I miss the +.3. What can I be doing that gives me a -.3 advantage? 

[int2str]

?

 

I can haz E46 subframe connector mod factor reduction/removal plz?

[ssmith]

18 minutes ago, yuba said:

You can very easily manipulate the power curve with it by closing the throttle body at higher RPM.  Make more power, close the throttle body to keep the average down, more area under the entire curve.

A restrictor plate is nearly as effective, and the compliance sheet already takes the flatness of the power curve into account.  It has been said an electronic throttle helps with traction control or flat shift but most systems I've seen use fuel or ignition cut.  So yeah, I don't see the point of having the modifier at all, but no matter which way Greg goes someone is going to be unhappy.

[BringBack4drmodfactor]

Thank you for posting this in advance to review:
 

I also feel it makes no sense to have a 305 limit in either class ST3 or ST2. I’m just echoing the overwhelming opinion to get rid of it or at least make it 315 and below. It does you no good if your rules push everyone to a different series.

Count me as 1 less driver and 1 less instructor on the grid if 305+ rule isn’t modified to 315 or deleted.

 

 

 

 

 

[Phloozy]

10 minutes ago, ssmith said:

A restrictor plate is nearly as effective, and the compliance sheet already takes the flatness of the power curve into account.  It has been said an electronic throttle helps with traction control or flat shift but most systems I've seen use fuel or ignition cut.  So yeah, I don't see the point of having the modifier at all, but no matter which way Greg goes someone is going to be unhappy.

This is what I dont get. I don't think I can do any of that and the rules already stop funky dyno tuning. So why is there a .3 hit? Is flat foot shifting really worth that much even if it can be done? What cars in ST/TT5 are getting much benefit at all from having an electronic tb

[Chris W.]

My region has lots of pony cars in ST2 - they're too heavy to be competitive in ST3 on our shorter tracks in Arizona, but every one of them runs a 315 tire as well 2. the .-3 will definitely have a notable impact for those cars versus the lighter options. 

I look to the results in my region and some other close regions for insight - but have heavier cars on wider tires been dominant in other regions?

[Bryan Heitman]

Does anyone know how to take 700 pounds out of a MX5? I need to lose 700 pounds to meet the top of ST4 class. Maybe a good diet recommendation? 

[surlynkid]

Standard available size from Hoosier and Hankook is 315/30-18.  Those are the only rears for me to run in ST2.  I shouldn’t take a hit for that.  OEM wheel size is 12” wide.  Even a 305 or 315 is stretched.  Agree that the penalty doesn’t start until above 315 printed on the sidewall. 

[mslevin]

The aero changes in ST4 look great, looking forward to making some changes for next year. Sounds like this will allow our GTS friends to come to the dark side. The ABS limitations may annoy some people but, IMO, are fair.

[Bryan Heitman]

What is the basis for the spec racer ford being approved in-class with SADEV while the mx5 is penalized? There is non-SADEV and SADEV versions of the SRF3.

 

[LStillman]

Greg, if you are going to allow up sized splitters in ST4 with a modifier can we do away with the 1" airdam piece if you take the modifier?  Any splitter past 6" is going to add significant drag so this gets rid of the need to easily measure.

 

Some of us are unable to use a splitter under the current ST4 ruleset because the 1" airdam will cause overheating.  

[daytonars4]

2 hours ago, Chris W. said:

My region has lots of pony cars in ST2 - they're too heavy to be competitive in ST3 on our shorter tracks in Arizona, but every one of them runs a 315 tire as well 2. the .-3 will definitely have a notable impact for those cars versus the lighter options. 

I look to the results in my region and some other close regions for insight - but have heavier cars on wider tires been dominant in other regions?

 I think midatlantic is probably one of the few regions where we see the issue on display weekly in ST3. We have certain modern cars in class that are able to exploit the 2022 rules. They max out the bonus weight mod while also running 335 or 345 square setups. It creates a situation where they are the fastest cars on the straight by 2-3mph AND also have a 30% wider tire than competitors on 275's. But the issue with the new change is those moderns cars that were at 3400lbs didn't max the weight mod yet. So with the .3 mod, they will noW push to 3600lbs which gains them a .2 bonus. Effectively makes this a net .1 mod. Not all that effective of a rule change....  

[Bryan Heitman]

Only 2-3mph? I'd be thrilled with that!

[daytonars4]

2 minutes ago, Bryan Heitman said:

Only 2-3mph? I'd be thrilled with that!

You would be thrilled with being on a 30% smaller tire AND getting beat by 2-4 car lengths on every straight? The things that excite you are rather odd.lol 

[Grant Ellis]

4 hours ago, Emag said:

Agreed with Scott.

The torque numbers and weight modifier is more of an influence than tire size in ST3 and ST2, with some track dependance. 

If we look at 2021 Daytona Nationals ST3 was very equal with various, almost opposite configurations.  I remember the group leader told me in the dyno line that the data traces were almost identical among the top finishers. 

I was 3rd place at Daytona in TT3!

the top 3 cars were a Porsche, Z350 and a C5 Z06 and the 4th place was a Mustang! Can’t ask for a much better BOP than it already was!!

I THINK THIS TIRE CHANGE IN TT2 and TT3 needs to be dropped. 

[Bryan Heitman]

This sounds rather close for sure. It's more like +15-20mph in my car so yes 2-3mph I'd be fine with.

[Tykrane30]

44 minutes ago, daytonars4 said:

 I think midatlantic is probably one of the few regions where we see the issue on display weekly in ST3. We have certain modern cars in class that are able to exploit the 2022 rules. They max out the bonus weight mod while also running 335 or 345 square setups. It creates a situation where they are the fastest cars on the straight by 2-3mph AND also have a 30% wider tire than competitors on 275's. But the issue with the new change is those moderns cars that were at 3400lbs didn't max the weight mod yet. So with the .3 mod, they will noW push to 3600lbs which gains them a .2 bonus. Effectively makes this a net .1 mod. Not all that effective of a rule change....  

@daytonars4 Why are you limited to a 275? the current rules aren't stopping you from running a larger tire.

[Kevin Harvey]

Greg,

First, I understand the position you are in and we have had our differences on rules changes over the past 12 years.  

Second, I am also in the camp of deleting the ST2-3 >305mm tire size rule.  There is already great parity among the ST2 and ST3 fields between vehicle makes, tire brands, and tire sizes.  If anything, penalize any tire >335 in ST3 but I am a firm believer in leaving ST2 completely open.  The car weights, power levels, braking packages, aero, etc. all need a larger tire.  Not just for performance, but for longevity and cost control.  I raced on 275s for years and my tire budget was at least 3x more than when I switched to 315s.  

[Bgoldburg]

I run a Panoz in ST1 for over a decade using competition tires accepting the -0.5 tire penalty and my chassis penalty.   I used to run Michelin 30/65 and 31/71 and I was 3100lbs

I'm now 2700lbs in ST2 and switched tires to the new Hankook slicks since they now have a NASA contingency (which is excellent).  They have 30/66 and 32/71 which matched my rims and setup.  

I already take a -0.5 deduction for a competition tire and you want me to add another -0.3 deduction for a 320mm rear tire??

Why?  I have 300whp and need all the grip I can get...

That's extreme!!!  Leave ST2 out of a tire size limit penalty.   We don't want it.  My entire region would have to buy rims for no reason.....

Brian

 

Edited November 17, 2022 by Bgoldburg

[ssmith]

49 minutes ago, daytonars4 said:

 I think midatlantic is probably one of the few regions where we see the issue on display weekly in ST3. We have certain modern cars in class that are able to exploit the 2022 rules. They max out the bonus weight mod while also running 335 or 345 square setups. It creates a situation where they are the fastest cars on the straight by 2-3mph AND also have a 30% wider tire than competitors on 275's. But the issue with the new change is those moderns cars that were at 3400lbs didn't max the weight mod yet. So with the .3 mod, they will noW push to 3600lbs which gains them a .2 bonus. Effectively makes this a net .1 mod. Not all that effective of a rule change....  

They have to add 200 lbs to counter the effect of the larger tire.  Isn't that the point, that light cars shouldn't be allowed to have as large of a tire as a heavy car, in order to equalize cornering speeds?

It isn't as easy to balance the straight line speed as some tracks have higher speed sections than others, and a heavier car will always have an advantage in the high speed straights as aero drag robs the same amount HP regardless of weight, and heavier cars have more HP.  Mod factors that work at VIR wouldn't make any sense at Sonoma.

[Tansar_Motorsports]

ST4 aero rules look great IMO.  should make crossover from other series and organizations much easier.

Super happy to see mod factors for solid rear axle in st4 and below, should increase the number of competitive chassis options.

Super super super happy to see ST5 target ratio increase slightly.  Should make it easier for the various 4 cylinder NA cars to be able to use toyos and still make the target ratio.

 

One clarifying question:  The way the A-arm penalty is worded, it could be misinterpreted as being -0.5 for front double A-arms, and -0.5 for rear double A-arms (for a total of -1.0).  Instead of saying "front or rear", I would say "front and/or rear".

 

Overall, looking at NC miata, RX8, S2K, BRZ/FRS in ST5:  0.2 change for A-arm adjustment, and 0.5 change for overall target ratio.  --> overall change of 0.3.  So for a 2800lb car with only a rear wing, on Toyos, your target ratio would go from 12.9 to 13.2,  so an average power target of 212HP vs 217HP.

It helps.

[daytonars4]

22 minutes ago, Tykrane30 said:

@daytonars4 Why are you limited to a 275? the current rules aren't stopping you from running a larger tire.

The reason the modern cars are effective on a 335/345 is bc some of them have 3k rpm of peak hp which is their avg. With how the calculator works, the old BMW's with S54's only have 1500 rpm of peak hp. So switching to a 335 tire to match them makes the mph and straight line delta so massive it's like being in a different class. The whole point of BOP is so someone is supposed to choose. You are either faster on the straights or in the corners, in theory. But with how the weight mod and ST calculator works, some modern cars get both the straight line advantage and massive tire advantage. I still don't understand why the weight mod needs to be in place bc that mod is what is undermining the BOP theory behind some of the other ST rules.