UPDATE ST4/TT4 and other for 2017

[heavychevy]

May I suggest drivers be able to.use the old.method of peak hp as well. If its a matter of paperwork, a dyno sheet is easy to get and many already have one for their car. There is no competitive advantage to peak hp vs avg.. It may seem easy to NASA vets to pick this up but for a new person who is also trying to figure out all of the class rules, to add a more complicated dyno certification could prevent someone from trying (especially in TT). Since its all just paperwork in most regions I assume, verification is even easier by just looking for the highest number on the graph printout and their scale weight. They can upgrade to avg hp when they are ready to get more for their hp, at which point the old graph is tossed. At least possibly give the discretion to the regional directors. People having to download winpep to print a file is going to make it more difficult.

[fbirch]

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.

 

The crossover is likely to come from GTS3. At 11-to-1, most BMW's in GTS3 will be very close to the 11.3 or 11.4 level they'll need to run in ST4. A restrictor plate or other small tweak will get them there. GTS3 is also populated with more cars than GTS2 in most of the regions where I've paid attention to field size.

 

I currently run an e36 in GTS2 and will be bumping it up to GTS3 sometime next year, because that's where most of the competition runs at my home track. Once I'm in GTS3, supersizing into TT4 will be a nice option. I don't plan to run ST4, but it's a nice option to have if/when visiting other tracks where ST is bigger than GTS.

 

Felix B.

NOLA region, GTS2

[daytonars4]

ST3 is already the easy crossover for GTS3. In my region pretty much all the guys that crossed over were able to just remove weight to make the 9.7 transition to ST with their e46 M3's. So you are essentially making ST3 and ST4 the crossover options for GTS3. Would seem more logical to me to make a crossover for GTS2 and Spec46 rather than having both ST3/4 as the GTS3 crossover. Someone like you with an e36 S52 can still easily transition to ST4 by dropping weight from GTS2 or adding weight to drop down from GTS3. I just can't see any negatives by going to 13 to 1. I think HC even has an easier transition to 13 since they are roughly in that ballpark already.

 

Most regions have 2 race groups. ST4 pace wise in the 11's would probably be too fast to be allowed in lighting. I think what is more likely is that ST4 would be in Thunder at the 11.3 to 1. Which means in the same group as GTS3 anyway, so no super sizing. GTS2 and Spec 46 easily run in lighting, which means at 13 to 1 they can supersize ST4 in Thunder. If you want volume in ST4 quickly this is the way to do it. Also think about how bad of an idea it is to end up with ST4 (11.3) and GTS3 (11.0) on track in Thunder together st the same time. There's no way you can avoid in class racing with cars that are prepped to a very similar level. At 13 you are giving GTS3 enough of a gap to hopefully prevent major issues.

 

Lawrence Gibson

Mid Atlantic GTS2

[fbirch]

For me personally, 12/11.3:1 works better because my only interest in supersizing is TT4, not ST4, and it's a little easier to get there from GTS3. But you make some valid points that are applicable to a broader audience, and I would have been okay with ST4/TT4 at 13:1. However, the initial proposal has been 12:1 for a long time and now the 2017 rules have been posted. I don't think there's much chance to change it for 2017 at this late stage.

 

Felix B.

NOLA region, GTS2

[daytonars4]

A lot of the support from the GTS2 crowd was bc we saw 12 as the bottom and essentially Hoosiers etc would end up raising the ratio. For example, running a R7 275 would go from like 12 to a 12.7 etc. I know I personally wasn't expecting to start at 12 and then receive more power credit for running the max tire allowed in the class. Running the max tire in ST3 keeps you at the base ratio, not giving you a bonus of more power. So keeping the ratio is fine if that's the decision, but 12 should be for someone on like a 225 Toyo with no aero. Then everyone else made slower from there. For me personally it makes no difference. I have an A5 and an e36 S54. But if I actually want to have a field to race against the as-is plan would pretty much have me alone or with 1 or 2 other cars.

[Jon B.]

A lot of the support from the GTS2 crowd was bc we saw 12 as the bottom and essentially Hoosiers etc would end up raising the ratio. For example, running a R7 275 would go from like 12 to a 12.7 etc. I know I personally wasn't expecting to start at 12 and then receive more power credit for running the max tire allowed in the class. Running the max tire in ST3 keeps you at the base ratio, not giving you a bonus of more power. So keeping the ratio is fine if that's the decision, but 12 should be for someone on like a 225 Toyo with no aero. Then everyone else made slower from there. For me personally it makes no difference. I have an A5 and an e36 S54. But if I actually want to have a field to race against the as-is plan would pretty much have me alone or with 1 or 2 other cars.

 

As a past GTS2 competitor, I would disagree with this. 12:1 along with there being modifiers depending on tires, etc has been in the discussion for a long time. Let's keep it where it's at so that we can get started and keep it consistent with the progression down from ST3. It may be that for those who do not want to drop weight or add HP, that the upcoming ST5 class will be a better landing spot for some GTS2 or Spec46 cars. While 11.3 might be a stretch for some (it is for me) what I like about how it's currently setup is that it gives people choices/options which I think does open it up to more cars if you don't just focus on GTS2 or SpecE46 cars as they currently sit. If you want to run 275s, great, but you can't run as much HP. If you want to run 245's with R7's, great, you can run your car lighter. If you want to run A7's, you can do that as well at 13:1. It will be interesting to see what will work and what won't and that's part of the fun.

[Snowmants]

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?

 

+1 Thanks!

[Mike 40]

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.

 

I'm wondering the same thing here. I certainly have not found AWD platforms to provide an advantage over a comparably prepared RWD platform (especially not 0.5 worth of an advantage).

 

Also, would a 245/35/18 R7 fall under the "Size 245 or smaller (DOT-approved)" line in the rules?

[Balroks]

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.

 

I'm wondering the same thing here. I certainly have not found AWD platforms to provide an advantage over a comparably prepared RWD platform (especially not 0.5 worth of an advantage).

 

 

Also, would a 245/35/18 R7 fall under the "Size 245 or smaller (DOT-approved)" line in the rules?

 

This. We always pray for rain and even then the highly developed C5/6's still outnumber and outrun us. If the concern was Evo/STI then I wouldn't worry as the car would run so poorly at that low of power it wouldn't be worth it. Not to mention how much heavier (esp at the front) most AWD's are compared to their RWD counter parts, then power is the only thing that can make up for it.

 

For the 245 question, Yes they can take the + points.

[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 the 2nd part of this rule be re-written in a less subjective fashion?

 

a bumper cover designed to push air flow up and/or around the front of the car could be considered as having an aspect that functions as a canard to provide direct downforce.

but every bumper cover is going to be designed to deflect air up resulting in downforce, or deflect air out around the front tires producing downforce.

some people might define a canard as a vortex generator providing downforce by preventing air from entering under the side skirts. any small curve out on a replaced front fascia could be considered to function the way.

[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.

 

Quoting myself to try and get an answer. Also, if this rule is designed to keep costs down it seems a bit silly to not allow something simple like this but to still allow much more expensive things like very high end 4-way adjustable dampers, etc. I know mounting point modifications can probably be taken much further, but I wasn't expecting to have to have something that was allowed for my car in P/TTB to not be allowed in S/TT4.

[Jon B.]

 

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.

 

 

 

You should be fine with those mounts. You are not changing anything on the chassis, just using different shock/damper mounts.

[panozracing]

Yes, ST1 should move to 6.0:1 with the Avg HP, and ST2 will stay at 8.0:1 using Avg HP.

 

So,

ST1 6.0:1

ST2 8.0:1

ST3 10.0:1

ST4 12.0:1

PTC 14.5:1 for '17 (maybe)---but using the ST Formula and Avg HP

 

Why the change in ST1 to 6.0:1? That really stinks. I saw your post saying its to try and increase car counts. Why do you think that? Most of the cars are detuning to get to those numbers already. I will have to add over 100lbs to my car. I have spent so much time (and money) getting the car as light as possible. I am carb'ed and already restricted. I cant take any more HP out without a new motor. I have been racing NASA for almost 10 years with the same basic rules. I have never heard anyone complain about difficulties getting to 5.5:1. Please consider leaving it at 5.5:1.

 

The Avg/HP calc lowers my HP (probably because I am carb'ed) and will probably raise the HP on all these ECU detuned LS motors being creative. So that is good I guess. Really something needs to be done about an ECU sensing the front wheels moving and altering the tune without any user input. This is currently legal in all ST classes and needs to be controlled.

[Vettedoctor]

Really something needs to be done about an ECU sensing the front wheels moving and altering the tune without any user input. This is currently legal in all ST classes and needs to be controlled.

 

First off - this is not legal in all ST classes - that is deliberate cheating and is definitely illegal! Take a read through section 8.3 in the ST rules:

Vehicles may not have any adjustments during the competition day to systems that allow adjustment of horsepower levels that would serve to alter Dyno readings

What you're talking about above is exactly that!

 

Second - these are the kind of posts that give ST a bad rap, has anyone actually proven this to be the case?

Greg - have you heard of or caught anyone doing this?

[panozracing]

Really something needs to be done about an ECU sensing the front wheels moving and altering the tune without any user input. This is currently legal in all ST classes and needs to be controlled.

 

First off - this is not legal in all ST classes - that is deliberate cheating and is definitely illegal! Take a read through section 8.3 in the ST rules:

Vehicles may not have any adjustments during the competition day to systems that allow adjustment of horsepower levels that would serve to alter Dyno readings

What you're talking about above is exactly that!

 

Second - these are the kind of posts that give ST a bad rap, has anyone actually proven this to be the case?

Greg - have you heard of or caught anyone doing this?

 

Well that is the main issue. Interpretation of the rule. I disagree that its not legal. There are no physical alterations being done to the ECU. The ECU remains sealed and not modified via wifi or anything like that. The computer is simply running its program just like A/F ratio adjustments etc. One could call it a poor mans traction control and de-tune when wheel speeds differ..... I think the rules need clarifications and some way to catch this programming capability. I don't know any NASA racers doing this but I do know a shop that said they have done it. So you are correct I dont have actual proof (I didnt see the programming or anything like that).

 

These computers are tough on us carb'ed guys...lol.....dying breed probably....

 

I am not trying to stir anything up. I just know computers and when you get really smart people and computers together fancy stuff happens.

 

How are things coming with a GPS based unit to place into cars randomly as they pull out onto the track?

[Snowmants]

That's sad.... these aren't pro teams competing for mega money.... If you have to cheat to win your victory is going to be pretty hollow. I would hope no one is doing that.

[panozracing]

That's sad.... these aren't pro teams competing for mega money.... If you have to cheat to win your victory is going to be pretty hollow. I would hope no one is doing that.

 

Is it though? I am not condoning any of this but I am not sure it even violates the rules. The ECU is running a program and adjusting to the environment. That is what an ECU does. If nobody is touching it how is it different than any other constant ECU modification that it has to be doing to make the engine run?

[Mrsideways]

Really something needs to be done about an ECU sensing the front wheels moving and altering the tune without any user input. This is currently legal in all ST classes and needs to be controlled.

 

First off - this is not legal in all ST classes - that is deliberate cheating and is definitely illegal! Take a read through section 8.3 in the ST rules:

Vehicles may not have any adjustments during the competition day to systems that allow adjustment of horsepower levels that would serve to alter Dyno readings

What you're talking about above is exactly that!

 

Second - these are the kind of posts that give ST a bad rap, has anyone actually proven this to be the case?

Greg - have you heard of or caught anyone doing this?

 

It's called "tech shed legal". Ask Spec Miata about that. If you applied current tech shed procedures to the nascars that won races in the 60's they'd all be illegal now. People push the envelope any way they can. It's a reason why I'm particularly against Dyno based classing. I think it lends it's self to lots of ways to "trick" the dyno. That and no two dyno's read alike. Two different dynojets here in town that are the same dynojet and i made NO changes to my car yet read nearly 15% different.

I've been working on a way of calculating engine displacement and rpm with some modifiers to figure out a way of classing cars based on an engine making the max of what it can make at a particular RPM. the bad news is it screws american V8's because their HP to Displacement is poor compared to european and japansese cars and basically requires you to either drop the rev limiter way down or build a motor. But running the numbers on existing racing and existing classes it seems to work pretty well. No dyno, no tech shed, no tear down. I'm gonna keep working on it for afew more years though.

[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 like max class 275 tires would reduce power and not increase it.

 

 

Something else to consider is that TTB is being eliminated in exchange for TT4. 4 of the 8 registrations in TTB Midatlantic this weekend are e36 M3's which can not make the 11.3 ratio. I'm not sure if this is the most common car for the class or just a regional thing. But if it is indeed the car most impacted by the elimination of TTB I would think it should be considered into setting the TT4 ratio. And yes, someone could "just run Hoosier A's." But what is apparent from setting a 1.0 mod is that it wasn't set to level the field, it was a ratio set as a deterrent. GTS3 runs a 1.0 mod for slicks vs DOT and all the top guys run DOT. So the gap between R7's and A7's is clearly going to be less than slick vs DOT. So at 20whp loss, I find it unlikely anyone will be even remotely as fast on an A vs R tire which is clearly the intent.

[Snowmants]

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 like max class 275 tires would reduce power and not increase it.

 

 

Something else to consider is that TTB is being eliminated in exchange for TT4. 4 of the 8 registrations in TTB Midatlantic this weekend are e36 M3's which can not make the 11.3 ratio. I'm not sure if this is the most common car for the class or just a regional thing. But if it is indeed the car most impacted by the elimination of TTB I would think it should be considered into setting the TT4 ratio. And yes, someone could "just run Hoosier A's." But what is apparent from setting a 1.0 mod is that it wasn't set to level the field, it was a ratio set as a deterrent. GTS3 runs a 1.0 mod for slicks vs DOT and all the top guys run DOT. So the gap between R7's and A7's is clearly going to be less than slick vs DOT. So at 20whp loss, I find it unlikely anyone will be even remotely as fast on an A vs R tire which is clearly the intent.

 

It will also be VERY hard for s2000s to make the 11.3:1 ratio.

[NorcalTT]

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 like max class 275 tires would reduce power and not increase it.

 

 

Something else to consider is that TTB is being eliminated in exchange for TT4. 4 of the 8 registrations in TTB Midatlantic this weekend are e36 M3's which can not make the 11.3 ratio. I'm not sure if this is the most common car for the class or just a regional thing. But if it is indeed the car most impacted by the elimination of TTB I would think it should be considered into setting the TT4 ratio. And yes, someone could "just run Hoosier A's." But what is apparent from setting a 1.0 mod is that it wasn't set to level the field, it was a ratio set as a deterrent. GTS3 runs a 1.0 mod for slicks vs DOT and all the top guys run DOT. So the gap between R7's and A7's is clearly going to be less than slick vs DOT. So at 20whp loss, I find it unlikely anyone will be even remotely as fast on an A vs R tire which is clearly the intent.

 

Something else to consider is that TTB had a minimum Adjusted Power to Weight ratio of 10.5:1, so I don't know if that's a valid argument if you think outside the box of an e36 M3 or S2000 which we have to do at a National level. On the West Coast, the car that has won TTB consistently is not an e36 M3, but an old Pontiac Firebird.

 

Let's keep ST4 consistent and stick with the original intent, as started in this thread months ago. ie

ST1 6.0:1

ST2 8.0:1

ST3 10.0:1

ST4 12.0:1

[ja1217]

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 like max class 275 tires would reduce power and not increase it.

 

 

Something else to consider is that TTB is being eliminated in exchange for TT4. 4 of the 8 registrations in TTB Midatlantic this weekend are e36 M3's which can not make the 11.3 ratio. I'm not sure if this is the most common car for the class or just a regional thing. But if it is indeed the car most impacted by the elimination of TTB I would think it should be considered into setting the TT4 ratio. And yes, someone could "just run Hoosier A's." But what is apparent from setting a 1.0 mod is that it wasn't set to level the field, it was a ratio set as a deterrent. GTS3 runs a 1.0 mod for slicks vs DOT and all the top guys run DOT. So the gap between R7's and A7's is clearly going to be less than slick vs DOT. So at 20whp loss, I find it unlikely anyone will be even remotely as fast on an A vs R tire which is clearly the intent.

 

It will also be VERY hard for s2000s to make the 11.3:1 ratio.

 

Don't forget the FR-S/BRZ's! I'm one of the 8 signed up for TTB this weekend in MidAtlantic and have been building my car this year with TT4/ST4 in mind. I'm already struggling to get anywhere near a 12:1 ratio and getting down to 11.3 would almost certainly require either a heavily built engine or forced induction.

[daytonars4]

The issue is not really the ratio, its how the mods are being applied. Giving someone running the max tire allowed in a class MORE power is not consistent with the other TT/ST classes and is what is causing the problem. If someone runs a 335 tire in ST3 they are not given MORE power. They are at the base power of the class. So giving more power to someone running a 275 which is the max allowed is not consistent in theory with the other classes. If the base tire for ST4 is 225, then a 245 should move you to 12.3 and a 275 to 12.7 etc. For simplicity, carrying the same mod across all classes for all tires you have to go to 13. Otherwise ST4 needs unique mods (275 is -.7 instead of +.7). This corrects the issue with many cars fitting power wise. But if everyone is in favor of setting a ratio that a large number of the cars interested in the class can't fit, then have fun.

[phat ralph]

No Modification Factor Models:

 

Thunder Roadster pre-'08 body/no-wing type = -0.0 (no aero) (ST4 approved w/ spec. tire)

 

So, does this mean you have to use the Hoosier "880 Roadster Edition" tire purchased from USLC/600 Racing with no contingency or are you able to run the Hoosier "880" with contingency and the ability to purchase at Hoosier Tire dealers beside 600 Racing? Are you able to run in ST4 with Hoosier DOT A7's with a deduction modification? Thanks!

[Mrsideways]

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 like max class 275 tires would reduce power and not increase it.

 

 

Something else to consider is that TTB is being eliminated in exchange for TT4. 4 of the 8 registrations in TTB Midatlantic this weekend are e36 M3's which can not make the 11.3 ratio. I'm not sure if this is the most common car for the class or just a regional thing. But if it is indeed the car most impacted by the elimination of TTB I would think it should be considered into setting the TT4 ratio. And yes, someone could "just run Hoosier A's." But what is apparent from setting a 1.0 mod is that it wasn't set to level the field, it was a ratio set as a deterrent. GTS3 runs a 1.0 mod for slicks vs DOT and all the top guys run DOT. So the gap between R7's and A7's is clearly going to be less than slick vs DOT. So at 20whp loss, I find it unlikely anyone will be even remotely as fast on an A vs R tire which is clearly the intent.

 

It will also be VERY hard for s2000s to make the 11.3:1 ratio.

 

Yes, it requires a K24 or a K24 crank in a F block. Mine is 10.7:1 with a K24 and no ballast on the higher reading dyno in town, on the lower reading (no idea which is right) it's 11.6:1 (yes both Dyno's are the same model Dynojet). However I know the A tire is about a second a lap faster on the local track then the R. And 1 seconds at the speeds these cars are running is more then 1.0 of power to weight. So I need to be 12.4:1 to run the A.