UPDATE ST4/TT4 and other for 2017

[Snowmants]

 

I think if you only do section 1 of D) you can apply the +.4 OEM Aero Factor but if you do section 2 than that factor goes away. Might be easier to read if ST4 Aerodynamic Modification Allowances turned into its own lettered section ie. E)

 

Jon

 

Ok--I read it that for ST4 only, you were allowed to have basic front splitter/wing and it still just counted as OEM aero.

Otherwise why would they even have included that section 2? I guess we need more clarification...

Section 1 is what can be done and still considered "OEM Aero". Nowhere in Section 1 does it list front splitter/wing.

 

Once you start doing things listed in Section 2, the OEM Aero Modification Factor can not be used.

 

Aerodynamic parts/devices/aides shall be limited in ST4 to the following:

a) All of the items listed above in section 7.3.2.D.1) “OEM Aero” Modification Factor.

 

This is just stating that you can still do the stuff listed in Section 1, not that you can still use the "OEM Aero" Modification factor.

 

Ok I'm with you....I guess for the higher classes like TT1/ST1 TT2/ST2 aero is unrestricted unless you are claiming OEM aero, whereas in ST4 if you don't claim oem aero, you are still capped in terms of what aero you CAN run(limited to the items in section 2 mentioned above). Is that right?

[NammyBoy]

Based on the way the rules are written, the Tire Size Modification Factor still applies for ST4. This is a bit strange, as the maximum tire for ST4 is 275, but you will take a +0.3 Modification Factor for running the maximum tire. Is it written elsewhere that the Tire Size Modification Factor does not apply to ST4? Did I miss it somewhere?

[Mike W.]

Ok I'm with you....I guess for the higher classes like TT1/ST1 TT2/ST2 aero is unrestricted unless you are claiming OEM aero, whereas in ST4 if you don't claim oem aero, you are still capped in terms of what aero you CAN run(limited to the items in section 2 mentioned above). Is that right?

The "OEM Aero" Modification factor is only available in ST4 and ST3. Yes, the aero modifications in ST4 are limited to what is listed in 7.3.2.D.1 and 7.3.2.D.2.

[Snowmants]

Ok I'm with you....I guess for the higher classes like TT1/ST1 TT2/ST2 aero is unrestricted unless you are claiming OEM aero, whereas in ST4 if you don't claim oem aero, you are still capped in terms of what aero you CAN run(limited to the items in section 2 mentioned above). Is that right?

The "OEM Aero" Modification factor is only available in ST4 and ST3. Yes, the aero modifications in ST4 are limited to what is listed in 7.3.2.D.1 and 7.3.2.D.2.

 

OK thanks for the clarification!

[Jon B.]

Based on the way the rules are written, the Tire Size Modification Factor still applies for ST4. This is a bit strange, as the maximum tire for ST4 is 275, but you will take a +0.3 Modification Factor for running the maximum tire. Is it written elsewhere that the Tire Size Modification Factor does not apply to ST4? Did I miss it somewhere?

 

It may have been written this way to keep the rules more simple. For ST4 it nets out to a +.4 mod factor for running a smaller tire like a 245. For ST3 and other higher HP classes, where larger tires than 275 are allowed, the mod factors will also work, but a 245 would get the +.7 mod factor.

[J_Roberts]

Yes a radical is a sports racer.

 

OK thanks, not that I am about to go buy a Radical. That was just an example for my main question. Let me try another, though again maybe not the best. Even though an FF 818 is a 'kit' car, it is a tube frame, mid engine, rear wheel drive, open cockpit, all fiberglass body vehicle. Is the difference is that it has doors, or that it can be made street legal? It does not fit the definition of a production car.

 

I suppose what my real question is, will there be a list of what cars fit into the higher correction factor class, or a more specific definition? In other words, a list of what cars are considered prototypes or sports racers, or what defines a prototype or a sports racer, just so there is no ambiguity?

[DrewC]

Glad I found this thread!

 

Impulsively bought a car for 2017 and am (was?) borderline TTD/C with its current state and garage full of parts. Guess I need to focus on rebuilding the essentials over the next month and hold off on ordering fun parts till the new rules are rolled out.

[Balroks]

Glad I found this thread!

 

Impulsively bought a car for 2017 and am (was?) borderline TTD/C with its current state and garage full of parts. Guess I need to focus on rebuilding the essentials over the next month and hold off on ordering fun parts till the new rules are rolled out.

 

There is a current version on the Nasa website as of this week.

[DrewC]

There is a current version on the Nasa website as of this week.

 

Right but there is no mention of the fairly significant potential P:W revision from this thread.

[ja1217]

"Relocation of suspension mounting points is not permitted in ST4."

 

Does this mean that items like roll center or bump steer correction pieces added between the front spindle and control arms would not be allowed in ST4? Or, does relocation imply modifying the chassis mounting points for suspension components?

Relocation means changing the actual suspension melting points on the frame, chassis, sub frame

 

Where does something like this fall with this rule?: http://www.raceseng.com/shock-top-rear-upper-mount-2-toyota-gt86-scion-fr-s-subaru-brz-2013-719#

 

The mount point where you screw everything in is still the stock location, but this allows the strut to sit a littler higher, allowing you to lower the car a little more without sacrificing bump travel. I'm currently using these as my coilovers have a very limited amount of height adjustment in the rear.

[Greg G.]

Greg,

 

The way I read the rules, the NASA NP01 is only allowed in ST2 and only in ST2 in Spec NP01 trim. Is this the case?

 

 

-Kevin

Hi Kevin, no the NPO1 can also run in ST1 or ST2 using the modification factor for prototypes.

We think that the -3.2 modification factor in ST2 is enough,

Along with the modification factors for transmission and weight.

Of course, these are always subject to change if necessary.

 

Makes sense. It is just the way the NP01 is called out in the last section made me think it was limited to ST2.

 

So no ST3 at all, right?

 

Correct, no sports racers, prototypes, monocoque purpose built race cars in ST3 or ST4, unless specifically listed in Section 7.5 (RSR, SRF, TR)

[Greg G.]

Based on the way the rules are written, the Tire Size Modification Factor still applies for ST4. This is a bit strange, as the maximum tire for ST4 is 275, but you will take a +0.3 Modification Factor for running the maximum tire. Is it written elsewhere that the Tire Size Modification Factor does not apply to ST4? Did I miss it somewhere?

 

It may have been written this way to keep the rules more simple. For ST4 it nets out to a +.4 mod factor for running a smaller tire like a 245. For ST3 and other higher HP classes, where larger tires than 275 are allowed, the mod factors will also work, but a 245 would get the +.7 mod factor.

Correct, keeping the same Mod Factors for tire size allows competitors to more easily adjust the vehicle to move up or down in class as needed. It also allows an "apples to apples" comparison of Adjusted Wt/HP Ratio between the classes.

[Greg G.]

Yes a radical is a sports racer.

 

OK thanks, not that I am about to go buy a Radical. That was just an example for my main question. Let me try another, though again maybe not the best. Even though an FF 818 is a 'kit' car, it is a tube frame, mid engine, rear wheel drive, open cockpit, all fiberglass body vehicle. Is the difference is that it has doors, or that it can be made street legal? It does not fit the definition of a production car.

 

I suppose what my real question is, will there be a list of what cars fit into the higher correction factor class, or a more specific definition? In other words, a list of what cars are considered prototypes or sports racers, or what defines a prototype or a sports racer, just so there is no ambiguity?

Well, I guess besides the "when I see one, I know it is one," the terms have been generalized in the industry by their use in multiple organizations. Basically, they are: purpose built, highly modified single or two-seat, closed-wheel, open or closed cockpit racing cars, often of monocoque construction--using significant ground effects and aerodynamic modifications. The FF 818 would not be one. Formula cars that have been fitted with an enclosed body (or fenders) ARE sports racers or prototypes or monocoque race cars. A few example would be the Superlite Aero, Diasio, Stohr, Dragon, West, LSR Prince, Radicals, NPO1, etc.

[TWI]

What is the thought behind adding 'windshield frame removal' to the +.3 non-factory roofline mod factor? That one seemed to come out of left field and will impact a number of cars that were built to the 2016 and prior rules.

[Greg G.]

What is the thought behind adding 'windshield frame removal' to the +.3 non-factory roofline mod factor? That one seemed to come out of left field and will impact a number of cars that were built to the 2016 and prior rules.

How do you figure that?

[TWI]

How do you figure that?

 

7.3.B,2

 

Modification of the OEM roof line and/or removal of the front windshield/frame is

permitted, but will be assessed via a Modification Factor in the “Adjusted Weight/Power

Ratio”

 

I guess I was reading it wrong. I was thinking windshield or frame but it appears the intent of the rule is windshield and frame. I think there are a fair number of cars with Lexan windshields that do not use the OEM frame.

[39088/1]

ST4 aerodynamic modification allowances:

2b Modified or replaced front fascia without canards/winglets or other aspects that function as canards/winglets to provide direct downforce.

 

could someone give an example of this?

specifically the "other aspects that function as canards/winglets to provide direct downforce."

 

does it mean any curve or bend of a replaced front bumper cover that could be considered an aspect that functions as a canard?

 

are canards allowed as long as the front bumper cover is oem and not modified?

 

thanks

[Greg G.]

ST4 aerodynamic modification allowances:

2b Modified or replaced front fascia without canards/winglets or other aspects that function as canards/winglets to provide direct downforce.

 

could someone give an example of this?

specifically the "other aspects that function as canards/winglets to provide direct downforce."

 

does it mean any curve or bend of a replaced front bumper cover that could be considered an aspect that functions as a canard?

 

are canards allowed as long as the front bumper cover is oem and not modified?

 

thanks

 

Yes, as of this minute, they are allowed as long as the bumper cover is from the trim model of the vehicle, as manufactured. HOWEVER, I'm not sure if this will be changed this coming week or not.

[NorcalTT]

" Other than the listed exceptions, every Production vehicle must retain its unmodified:

1) OEM frame rails/rear frame cross beam, and/or Unibody, and Sub-

frames/suspension cross-members (in their OEM locations)."

 

 

If a subframe has been repaired/welded due to cracking, does it have to be replaced to satisfy the rule above? Or, is the intent of the rule to not allow any performance enhancing modifications to a subframe/cross beam, etc?

[Greg G.]

" Other than the listed exceptions, every Production vehicle must retain its unmodified:

1) OEM frame rails/rear frame cross beam, and/or Unibody, and Sub-

frames/suspension cross-members (in their OEM locations)."

 

 

If a subframe has been repaired/welded due to cracking, does it have to be replaced to satisfy the rule above? Or, is the intent of the rule to not allow any performance enhancing modifications to a subframe/cross beam, etc?

No performance enhancements. I don't believe that any Race or Series Director would agree with a protest of a simple repair to a cracked subframe or frame.

[39088/1]

good example picture, thanks

what about something less extreme like an APR GT front bumper for an S2000?

bottom 2 pics on apr's page

http://aprperformance.com/racing-product/gt-bumper/

[Chase J.]

ST4 aerodynamic modification allowances:

2b Modified or replaced front fascia without canards/winglets or other aspects that function as canards/winglets to provide direct downforce.

 

could someone give an example of this?

specifically the "other aspects that function as canards/winglets to provide direct downforce."

 

does it mean any curve or bend of a replaced front bumper cover that could be considered an aspect that functions as a canard?

 

are canards allowed as long as the front bumper cover is oem and not modified?

 

thanks

 

Yes, as of this minute, they are allowed as long as the bumper cover is from the trim model of the vehicle, as manufactured. HOWEVER, I'm not sure if this will be changed this coming week or not.

 

When you say bumper cover from this trim model. Do you mean, it is only legal on CR models and not Base model S2000's?

[Dysenpham]

ST4 aerodynamic modification allowances:

2b Modified or replaced front fascia without canards/winglets or other aspects that function as canards/winglets to provide direct downforce.

 

could someone give an example of this?

specifically the "other aspects that function as canards/winglets to provide direct downforce."

 

does it mean any curve or bend of a replaced front bumper cover that could be considered an aspect that functions as a canard?

 

are canards allowed as long as the front bumper cover is oem and not modified?

 

thanks

 

Yes, as of this minute, they are allowed as long as the bumper cover is from the trim model of the vehicle, as manufactured. HOWEVER, I'm not sure if this will be changed this coming week or not.

 

Hi Greg- I know that it may change in the coming week, but if it doesn't, does that mean that the Honda S2000 CR lip/bumper is clear to be used by any year S2000 or only the CR models?

[daytonars4]

Is there any explanation as to why the AWD penalty is higher in ST4 (-.5) than ST3 (-.3)? Having a .5 mod for AWD (which works out to around 10whp) implies that there is an advantage that has to be balanced. Is there any data to support that idea at this power level? I have an e36 S54 that I raced last year and an Audi A5 that I raced this year. My pace in the e36 is slightly faster but I am competitive in both in GTS2. This mod now essentially says that the A5 is so much faster it needs a 10whp cut, which would actually put my A5 far off the pace of my e36. Now if you want to discuss rain racing then sure. In GTS2 trim my A5 is on pace with ST3 lap times so a .5 mod is pretty irrelevant. But in 2 years I have only been in 1 rain race. So making an AWD car slow for 95% of racing that occurs in the dry makes sense?

The ST4 power ratio is comparable to GTS3. How many AWD cars have been competitive in GTS3 at nationals which has a 0 AWD mod? 0 from what I have seen at ECC in 2015 and 2016. How many in ST3, also 0 from what I have seen. ST2 is also dominated by RWD cars. A properly setup car at ST4 power level on Hoosiers is not at a loss for corner grip. People like to assume that AWD gives you an advantage out of corners, and for mid to back pack drivers it might. But for front pack drivers comfortable with rotating a car I’d argue that AWD is somewhat of a disadvantage or neutral to be honest. The AIM data this year for my A5 and e36's does not warrant a 10whp cut from what I've seen.

[daytonars4]

Was the ratio setup with any cars in mind? My hope was that it would allow Spec46/GTS2 cars to easily cross over and essentially be a good place for supersizing. But the base of 12 to 1 is too high for that. Spec46 races at about 12.5 to 1 but would need to be at around 11.3 for ST4 which isn't really possible. The most common GTS2 cars have S52's and a 11.3 ratio on 245's is a stretch. ST has typically been a fairly weak class in Midatlantic, but what has helped it take off this year is the ST3 crossover with GTS cars. I think if ST4 had a ratio conducive to Spec46 and GTS2 it would be easy to see 10+ cars the first weekend. Otherwise it seems like a class waiting for dedicated ST4 builds which could be much harder to build out without having a base of cars to form the foundation. People tend to be less motivated to build cars for classes that are empty. With all the tire credits I think a 13 to 1 base opens the options up more. I think when some mentioned the 12 to 1 base it was the expectation that the mods would reflect the new class vs such huge credits from 12 for tires etc.