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Greg G.

UPDATE ST4/TT4 and other for 2017

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Brian L.
Let's please not do this tire debate ad nauseum. I think there are a lot of factors involved in why the e36s in NorCal have done well. Love ya Brian, but I agree with TC, build a better mouse trap. I agree with the 275 cap. I myself plan to run 255s in st4 because I am no faster on 285s than on 255s...that could be driver, whatever. St4 will be really cool, it's s great idea with a lot of enthusiasm for next year. Again let's please not kill it with analysis paralysis. I think the preliminary proposed rules look great as they stand. Peace!!!

 

Spoken like an owner of an E36 chassis hahaha!

 

Again, this isn't about E36 vs Nissan 350Z, that is just one example. Watch what happens in October when we run our NP01 on Hoosiers...

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Vmcclure60
A tire cap with a huge weight difference is just a non-starter if you ask me...

 

Car "A": 300hp, 3600lbs, 275mm tires.

Car "B": 191hp, 2300lbs, 275mm tires.

 

Does anybody want to predict which has the advantage under braking, which is where the bulk of the passing is going to be? Even if you give a 0.5 bonus to the HP car, and a 0.5 penalty to the light-weight, you still have a difference of over a half ton, on the same contact patch... This is to say nothing of how the two will fare loaded up in a corner.

 

Exactly.

 

In ST3 2300 lb car would lose 0.2 and 3600 lb car adds 0.3 so the heavy car has a 0.5 bonus to use for tires or other mods. Keep ST3 as is please.

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geeveepee
I'll let others weigh in with their thoughts, but my vote would be (at least for ST4) to have limits on tire width, but not ratios for weight to tire width.

 

I'll actually disagree. Testing has proven that if you over-tire a light weight, lower horsepower car you actually slow the car down, so I'm not entirely sure a tire width limit helps anybody in the lower ST classes.

 

I'd agree with that Glenn. There was a GTS2 car trying to run super wide a few years ago at Western Nationals and in talking to him later, he regretted that decision as the car couldn't get out of it's own way. It had great grip in the corners and braked well, but it was slow everywhere else. Given the choice of open, a cap, or some random ratio, I'd take open. Second choice would be a cap. Another question is, is tire width a national/global problem or are we making an issue out of a non issue? What are other series with open cars doing with regards to tire width?

 

If the argument against a weight-to-tire ratio is that owners of lighter cars will naturally self-limit at some optimum then there should be no objection to instituting a max ratio at or above that optimum.

 

A flat cap on max width clearly limits heavier cars more than lighter cars.

 

If the alternative is a truly open rule, then the mod factor for running smaller tires should be eliminated as well since this also favors lighter cars.

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jldefanti
Greg, Regarding #7, There are a significant amount of BMW E36/46 race cars, via GTS 2/3, that have cage tie-in's to the rear subframe to help with known subframe issues. Might need to think about how to not exclude these cars.

 

-tony colicchio

TC Design

 

Section 7.3.2 C 1. of the 2016 TT rules indicate that sub-frame connectors and cage reinforcements through the floor pan are to be assessed at the discretion of the National Director. I never understood why these were allowed in GTS and not in ST. They don't offer a performance advantage, just prevent the weak BMW subframe from ripping out. What will the National Director assess in 2017?

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soundguydave
A tire cap with a huge weight difference is just a non-starter if you ask me...

 

Car "A": 300hp, 3600lbs, 275mm tires.

Car "B": 191hp, 2300lbs, 275mm tires.

 

Does anybody want to predict which has the advantage under braking, which is where the bulk of the passing is going to be? Even if you give a 0.5 bonus to the HP car, and a 0.5 penalty to the light-weight, you still have a difference of over a half ton, on the same contact patch... This is to say nothing of how the two will fare loaded up in a corner.

 

Exactly.

 

In ST3 2300 lb car would lose 0.2 and 3600 lb car adds 0.3 so the heavy car has a 0.5 bonus to use for tires or other mods. Keep ST3 as is please.

 

Not exactly... In ST4, the "bonus" could NOT be used for tires, since there would be a cap on tire width, and a restriction on compound. Even if you do the math with the ST3 adjustments, you wind up with car "A" at an effective 11.7 ratio (300hp, 3510lbs), and car "B" at an effective 12.2 ratio (189hp, 2300lbs). Still well over a half-ton (yes, over 1,000lbs) weight difference, and restricted to the same contact patch. Even if the mod factors were swung out to 0.5 for both cars, you'd still have in excess of a thousand pound delta.

 

I agree with you; leave ST3 alone. BUT, for ST4, forget about the tire cap. The tire ratio as mentioned before is simple enough to police in impound. I would favor a 10:1 or 10.5:1 weight-to-width ratio keyed to declared weight, with no breakout allowance to simplify impound, and no "credit" for running skinny. 275mm on a pony car just isn't enough in SUPER TOURING to keep up with the flyweights. I would also favor leaving non-DOTs in the match, with something like a 0.5 modifier. Let the car owner figure out how to build a better mousetrap, but don't make it a question of who can find the best shock tuner.

 

With the 0.5 modifiers, here's what we'd have as a match-up:

 

Car "A": 300hp (11.5 ratio) 3450lbs. 345mm max tire width. Plenty of contact patch.

Car "B": 184hp (12.5 ratio) 2300lbs. 230mm max tire width. Plenty of contact patch.

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Here's my issue I think myself and several other folks in this thread have already commented on. I've built my car to be as competitive as possible in TTC this year to the current rule set. From everything I have read in this thread I've come to the realization there is nowhere for my car to end up next year without spending a boat load of money to make it competitive in TT4 or spend money making it slower for the new TTC rules.

 

Also before anyone says the average HP will work out in my favor and put me close to the new 14.5:1 limit of the 2017 TTC limit, I did a quick calculation and the car is still at 13:1 as it sits now with average HP. My car was very much built to be a top competitor in TTC and it definitely doesn't fit into next years rules. What's the point of having TTC and TTD so close together? Why not leave TTC very close to the current PTW so we don't have to spend money detuning the car for next year only to have to change it again for when TT5 comes? Makes no sense to me at all. Someone please have this make sense to me or else the car will probably just sit on Jack stands for the next year.

 

Also will torque ever be calculated into the game for figuring out PTW? Seems crazy that's never a factor...

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drivinhardz06
The ST and other power to weight classes are about building a better "mouse trap" If you have not built a mouse trap to keep up with mine, don't penalize me if what I did was with-in the rules. Build a better mouse trap.

 

-tony

 

Get out of here with that kind of nonsense. That's kooky talk.

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Brian L.
The ST and other power to weight classes are about building a better "mouse trap" If you have not built a mouse trap to keep up with mine, don't penalize me if what I did was with-in the rules. Build a better mouse trap.

 

-tony

 

Get out of here with that kind of nonsense. That's kooky talk.

 

Or we can do our best to build a rule set with the least amount of loop holes and areas to exploit, so that more than just the $100K+ cars need apply. I know, "kooky talk"

 

My vision of ST includes 40-50 cars fields between ST1-4, only going to happen if spending is "reasonably" capped and LOTS of cars can have a shot at winning.

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brkntrxn

Also will torque ever be calculated into the game for figuring out PTW? Seems crazy that's never a factor...

 

It shouldn't be in ST. If you are at a spot in your rpm band where you have more torque than horsepower, I can almost guarantee that you are in the wrong gear. Years of studying data proves that to me. If a turbo diesel ever shows up and beats me running 1500rpm everywhere, then so be it. They built a better mousetrap.

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Also will torque ever be calculated into the game for figuring out PTW? Seems crazy that's never a factor...

 

It shouldn't be in ST. If you are at a spot in your rpm band where you have more torque than horsepower, I can almost guarantee that you are in the wrong gear. Years of studying data proves that to me. If a turbo diesel ever shows up and beats me running 1500rpm everywhere, then so be it. They built a better mousetrap.

 

Spoken like someone who makes good torque numbers. Also my main competition makes more torque all the way through the power band and has won several national titles in his cars. http://www.nasaaz.com/classing/tt/2014/TTC%20-%20Joel%20Schotz.pdf Tell me again how he can make more horsepower than torque.

 

I still think it should be factored in somehow

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jon819
In the extreme case, we plan on running our NP01 in ST3 on Hoosiers just for fun at Sonoma coming up. Currently they equal ST3 lap times on 245 Toyo's, imagine what is going to happen when we put dot slicks on the car and take no more mod points. It will likely mean destruction of any sedan racecar, because our tire to weight ratio on this car will be so much better, even though it only runs 245's.

 

I think the NP01 can only run in ST3 if in complete spec form but St2 is fair game with Hoosiers and other mods.

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Brian L.
In the extreme case, we plan on running our NP01 in ST3 on Hoosiers just for fun at Sonoma coming up. Currently they equal ST3 lap times on 245 Toyo's, imagine what is going to happen when we put dot slicks on the car and take no more mod points. It will likely mean destruction of any sedan racecar, because our tire to weight ratio on this car will be so much better, even though it only runs 245's.

 

I think the NP01 can only run in ST3 if in complete spec form but St2 is fair game with Hoosiers and other mods.

 

Nope. Currently in the ST rules 245 Hoosiers take the same points as the 235 Toyo's it runs on now. I believe the "run as spec" thing you are referring to is that an NP01 doesn't currently need to dyno to prove HP ratings like other cars in regional races. It also needs to run 1800 lbs, which is only about 40-50 more than we have been running the car in past sessions where we have been as fast or faster than the top ST3 cars.

 

An 1800 lb NP01 only takes -.3 in weight adjustment over a 3000 lb car. Imagine the grip difference in the corners on the same tire as a heavier car. Imagine the braking difference. I have spent significant time in an NP01, on the current Toyo's I break at LEAST 1.5-2 brake markers later than I do in my Nissan.

 

edit: My apologies, I re read the announcement for the NP01 in ST3, and it does specify the Toyo. But why??? It is fully legal under the current rules with power to weight with a Hoosier. I wonder why the power that be decided to not let it run the same tire the heavier cars run on... hmm.....

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Jon B.
The ST and other power to weight classes are about building a better "mouse trap" If you have not built a mouse trap to keep up with mine, don't penalize me if what I did was with-in the rules. Build a better mouse trap.

 

-tony

 

Get out of here with that kind of nonsense. That's kooky talk.

 

Or we can do our best to build a rule set with the least amount of loop holes and areas to exploit, so that more than just the $100K+ cars need apply. I know, "kooky talk"

 

My vision of ST includes 40-50 cars fields between ST1-4, only going to happen if spending is "reasonably" capped and LOTS of cars can have a shot at winning.

 

Hi Brian - I think that most of us would share your vision of wanting to have larger fields of cars competing fairly. Many of us have also witnessed the downfall of a series where overly complex rules, in overreaction to a perceived 'problem' largely voiced by a minority of participants, were applied. Where I believe there is disagreement is:

 

1) the owners of the higher HP, heavier ('Big Bore') cars think they are at a disadvantage with regards to tire sizing as compared to the lower weight, lower HP ('Flyweight') cars in the turns. They are.

2) the Flyweight cars think they are at a disadvantage to the Big Bore cars on the straights. They are.

 

The advantages and disadvantages of either choice are what keeps things interesting. Depending on the track, the driver, aero, suspension, whatever, each type (Big Bore vs Flyweight) may have an advantage over the other on any given day. Look to the early days of SCCA Trans Am racing as an example.

 

Your premise is that applying a tire width to weight ratio will lower the cost of entry for a podium finish and remove loopholes to be exploited. Whereas others think that doing so will create more opportunity for those wanting to build 100k plus cars to take advantage of the rules. To a grassroots racer, removing weight (assuming driver development is given sufficient priority) ends up being a much more cost effective recipe for building a better mousetrap than any other option. You might take a short term hit up front, but the cost of consumables decreases, the car handles and brakes better, less stress is put on the motor thereby reducing the need to overspend on motor rebuilds, additional cooling needs, etc etc. Maybe a cap isn't the right answer and maybe the mod factors as written could be improved, but let's not kill the allure of a power to weight class by trying to apply a linear formula (tire width to weight) to a non linear scenario. Let the racers/market figure out what's best for themselves.

 

Also, trying to draw conclusions in comparing a modern, purpose built racecar such as a NP01 running on Hoosiers to older production based sedans/sports cars running on similarly sized Hoosiers doesn't make a lot of sense.

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flier129

Not exactly... In ST4, the "bonus" could NOT be used for tires, since there would be a cap on tire width, and a restriction on compound. Even if you do the math with the ST3 adjustments, you wind up with car "A" at an effective 11.7 ratio (300hp, 3510lbs), and car "B" at an effective 12.2 ratio (189hp, 2300lbs). Still well over a half-ton (yes, over 1,000lbs) weight difference, and restricted to the same contact patch. Even if the mod factors were swung out to 0.5 for both cars, you'd still have in excess of a thousand pound delta.

 

I agree with you; leave ST3 alone. BUT, for ST4, forget about the tire cap. The tire ratio as mentioned before is simple enough to police in impound. I would favor a 10:1 or 10.5:1 weight-to-width ratio keyed to declared weight, with no breakout allowance to simplify impound, and no "credit" for running skinny. 275mm on a pony car just isn't enough in SUPER TOURING to keep up with the flyweights. I would also favor leaving non-DOTs in the match, with something like a 0.5 modifier. Let the car owner figure out how to build a better mousetrap, but don't make it a question of who can find the best shock tuner.

 

With the 0.5 modifiers, here's what we'd have as a match-up:

 

Car "A": 300hp (11.5 ratio) 3450lbs. 345mm max tire width. Plenty of contact patch.

Car "B": 184hp (12.5 ratio) 2300lbs. 230mm max tire width. Plenty of contact patch.

 

No.

 

Have you ever ran a 180hp @ 2300lb car? That 300hp @ 3450lbs will BLOW past the lighter car after track-out....

 

My 130hp @2400lbs car gets absolutely annihilated by cars with 160hp or higher WITH the same power to weight in the same situation. If they have a better power to weight..... let me get their hotel key because they've checked the hell out.

 

Anecdote example sure, but concept carries over. Quit trying to make an issue out of a non issue. Build your car within the rule-set and go drive.

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geeveepee

...

Your premise is that applying a tire width to weight ratio will lower the cost of entry for a podium finish and remove loopholes to be exploited. Whereas others think that doing so will create more opportunity for those wanting to build 100k plus cars to take advantage of the rules. To a grassroots racer, removing weight (assuming driver development is given sufficient priority) ends up being a much more cost effective recipe for building a better mousetrap than any other option.

...

 

I don't disagree with your basic premise but there are definitely some nuances...

 

First, with no tire ratio, any Flyweight car that finds out someone actually HAS built a better mousetrap has the very easy option of upping their tire size. Regardless of mod factors, I think we can agree that this option is trivially easy compared to shedding the amount of weight needed to effect a similar improvement.

 

Second, there's a limit to how much weight can safely or effectively be removed from a given starting point regardless of time or money. If weight reduction is the only axis for modification then competition will drive development towards an essentially single car series because for any set of effectively equal handling vehicles, the lightest starting point will have an advantage that cannot be negated.

 

Third, it's not trivial for Big Bore vehicles to just drop weight since the one axis of power to weight is dictating reductions in power at the same time. So it's not just dropping raw weight, it's doing so at some ratio that maintains or improves the relative position versus the top dog Flyweight car. This is exactly what the rules are trying to prevent.

 

You do mention applying a linear solution to a non-linear problem and that's exactly the scenario you raise when talking about Big Bore vs Flyweight cars. If competition were linear within those buckets and non-linear between them, then the idea that you can choose to race at a local optimum within each bucket that is unobtainable by competitors in the other bucket is great. Certainly, let the best local optimum (the global optimum) win! But by maintaining a strict linearity in the rule set, the local optimum becomes the global optimum and there will inevitably be a convergence towards a single set up.

 

Non-linear rule sets must be a nightmare to devise and enforce, however, I think that adding a second axis of tire to weight is comparatively manageable

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Brian L.

 

Hi Brian - I think that most of us would share your vision of wanting to have larger fields of cars competing fairly. Many of us have also witnessed the downfall of a series where overly complex rules, in overreaction to a perceived 'problem' largely voiced by a minority of participants, were applied. Where I believe there is disagreement is:

 

1) the owners of the higher HP, heavier ('Big Bore') cars think they are at a disadvantage with regards to tire sizing as compared to the lower weight, lower HP ('Flyweight') cars in the turns. They are.

2) the Flyweight cars think they are at a disadvantage to the Big Bore cars on the straights. They are.

 

The advantages and disadvantages of either choice are what keeps things interesting. Depending on the track, the driver, aero, suspension, whatever, each type (Big Bore vs Flyweight) may have an advantage over the other on any given day. Look to the early days of SCCA Trans Am racing as an example.

 

Your premise is that applying a tire width to weight ratio will lower the cost of entry for a podium finish and remove loopholes to be exploited. Whereas others think that doing so will create more opportunity for those wanting to build 100k plus cars to take advantage of the rules. To a grassroots racer, removing weight (assuming driver development is given sufficient priority) ends up being a much more cost effective recipe for building a better mousetrap than any other option. You might take a short term hit up front, but the cost of consumables decreases, the car handles and brakes better, less stress is put on the motor thereby reducing the need to overspend on motor rebuilds, additional cooling needs, etc etc. Maybe a cap isn't the right answer and maybe the mod factors as written could be improved, but let's not kill the allure of a power to weight class by trying to apply a linear formula (tire width to weight) to a non linear scenario. Let the racers/market figure out what's best for themselves.

 

Also, trying to draw conclusions in comparing a modern, purpose built racecar such as a NP01 running on Hoosiers to older production based sedans/sports cars running on similarly sized Hoosiers doesn't make a lot of sense.

 

To respond to your numbered points, yes I can drag race current lighter cars on the straight at T Hill, but not by much at all, and certainly not enough to make up for 80% of the lap that is not spent on the straight away. People's answer on this thread to this? Build a lighter car.

 

Yes removing weight is a good long term, 100% agreed, but some cars just can't get as light as others. I have $8000 in dry carbon on my Z, and I am still 3100 lbs. So at some point it is NOT cost effective to remove weight. People reaction to this so far seem to be, choose a lighter platform.

 

If the rules stay the same, I fear it will limit growth. And yes, the market will sort that out, no one will choose to build a heavier car for the ST3 or ST4 class, which will limit growth. That is why I disagree with the "build a better mousetrap answer" answer to this, it is just short sighted.

 

Maybe it will take larger fields, more time, and more examples to prove my point. But the NP01 example is valid, given its an extreme example, but we are not talking about it being faster by a few tenths, and try to figure out if that is modern chassis or tire to weight. We are talking many seconds.

 

Can we at least agree that .3 power to weight is not enough between 1801 lbs, and 3199 lbs?

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brkntrxn

edit: My apologies, I re read the announcement for the NP01 in ST3, and it does specify the Toyo. But why??? It is fully legal under the current rules with power to weight with a Hoosier. I wonder why the power that be decided to not let it run the same tire the heavier cars run on... hmm.....

 

 

Ummm, maybe, just maybe, it is because the NP01 in ST3 is not forced to go by any of the other modification factors such as "non-production" vehicle, rear engine, and so on.

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Brian L.

edit: My apologies, I re read the announcement for the NP01 in ST3, and it does specify the Toyo. But why??? It is fully legal under the current rules with power to weight with a Hoosier. I wonder why the power that be decided to not let it run the same tire the heavier cars run on... hmm.....

 

 

Ummm, maybe, just maybe, it is because the NP01 in ST3 is not forced to go by any of the other modification factors such as "non-production" vehicle, rear engine, and so on.

 

That is 100% not true.

 

It takes all the mod factors like every other car...

 

Aprox 165 HP / 1800 lbs = 10.9

-.3 weight

-.4 non prod

-.2 rear engine

-.6 sequential

+.7 tire

 

= 10.1:1

 

Check my math, but it follows every rule, except not being allowed to run Hoosiers of the same size.

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brkntrxn

edit: My apologies, I re read the announcement for the NP01 in ST3, and it does specify the Toyo. But why??? It is fully legal under the current rules with power to weight with a Hoosier. I wonder why the power that be decided to not let it run the same tire the heavier cars run on... hmm.....

 

 

Ummm, maybe, just maybe, it is because the NP01 in ST3 is not forced to go by any of the other modification factors such as "non-production" vehicle, rear engine, and so on.

 

That is 100% not true.

 

It takes all the mod factors like every other car...

 

Aprox 165 HP / 1800 lbs = 10.9

-.3 weight

-.4 non prod

-.2 rear engine

-.6 sequential

+.7 tire

 

= 10.1:1

 

Check my math, but it follows every rule, except not being allowed to run Hoosiers of the same size.

 

 

Ok, makes sense.

 

I welcome them to run against me. If they beat me, then they bought a better mousetrap or simply outdrove me. I won't complain and say I am the underdog. I'll continue shadetree building my 13 year old Corvette that everyone thinks costs over $100k. I was REALLY looking forward to running against the NP01s in TT2 trim at ECC, but that will not happen for me. I will watch the times from afar to see how they compare. Hopefully Watkins will be a good side-by-side test of the TT3/NP01 trim and TT2 NP01 trims against the best on the East Coast.

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Greg G.
In the extreme case, we plan on running our NP01 in ST3 on Hoosiers just for fun at Sonoma coming up. Currently they equal ST3 lap times on 245 Toyo's, imagine what is going to happen when we put dot slicks on the car and take no more mod points. It will likely mean destruction of any sedan racecar, because our tire to weight ratio on this car will be so much better, even though it only runs 245's.

 

I think the NP01 can only run in ST3 if in complete spec form but St2 is fair game with Hoosiers and other mods.

 

Nope. Currently in the ST rules 245 Hoosiers take the same points as the 235 Toyo's it runs on now. I believe the "run as spec" thing you are referring to is that an NP01 doesn't currently need to dyno to prove HP ratings like other cars in regional races. It also needs to run 1800 lbs, which is only about 40-50 more than we have been running the car in past sessions where we have been as fast or faster than the top ST3 cars.

 

An 1800 lb NP01 only takes -.3 in weight adjustment over a 3000 lb car. Imagine the grip difference in the corners on the same tire as a heavier car. Imagine the braking difference. I have spent significant time in an NP01, on the current Toyo's I break at LEAST 1.5-2 brake markers later than I do in my Nissan.

 

edit: My apologies, I re read the announcement for the NP01 in ST3, and it does specify the Toyo. But why??? It is fully legal under the current rules with power to weight with a Hoosier. I wonder why the power that be decided to not let it run the same tire the heavier cars run on... hmm.....

Because they have more brains than looks!

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Greg G.

Also will torque ever be calculated into the game for figuring out PTW? Seems crazy that's never a factor...

 

It shouldn't be in ST. If you are at a spot in your rpm band where you have more torque than horsepower, I can almost guarantee that you are in the wrong gear. Years of studying data proves that to me. If a turbo diesel ever shows up and beats me running 1500rpm everywhere, then so be it. They built a better mousetrap.

Kevin, you better be careful. You keep agreeing with me, and I'll have to send you for a psych eval.

 

BTW guys, I refuse to get into a Torque versus power discussion here (again, for the hundredth time). We have moved to the Avg HP calculation to help even out those with flatter HP Dyno curves. Also, just curious, does your Torque wrench move in a circle faster when you torque to 300 lb-ft versus 30 lb-ft?

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Greg G.
I'm currently in a 11.75 Weight/Power Ratio car running TT3 because I was bumped up due to using after market brake module (Ford Racing). Assuming I meet the 12:1 ratio in the car with the after market brake module would the car be eligible for ST4?

I don't see anything proposed that would stop you.

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Greg G.
Looking for a clarification for 2017 for TTC. A lot of us are running dyno reclass with those relcasses giving us power:weight a lot lower than 14.5:1. Would those cars be given updated reclass numbers closer to 14.5? Seems like a big change given that we won't have the modification factor additions.

 

Probably not a lot lower than 14.5:1 using the ST Formula instead of the PT Formula and Avg HP. But, if they are a lot lower, you should be running in TT4. I will certainly be available to provide more Dyno re-class options for TTC/PTC for '17 once these rules come out. But, we would like to see the Dyno Re-classing go away (by '18).

 

Also, someone else asked why we are increasing the Adjusted Wt/HP for PTC/TTC. The answer is that we need the gap between ST4 and PTC--we should not have cars with the same Adjusted Wt/HP Ratio in two different classes. In order to ensure this, we need to compare apples to apples. So, we move PTC/TTC to the ST Adjusted Wt/HP Formula, using Avg HP, just like ST4/TT4. Then if there are cars in PTC/TTC that should be in ST4/TT4 because they are closer to 12:1 than 14.5:1, they need to move there this year, or significantly detune/ballast up. However, we will find that some of the top PTC/TTC cars will still be just fine at 14.5:1 using Avg HP and the ST Formula.

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Greg G.
The hardest part of this rule change roll out with one class at a time for me, and I am curious if others are in the same situation, is that I have started to build a TTB car that now will not be competitive in TT4 as I cant get to the power to weight with out a large cost increase. With the purposed TT5 PTW the car will fit perfect with some ballast but I cant step down to TTC for its last year due to points.. So I am basically in a situation that I sit with the car on jackstands not knowing what will or will not have a modification factor to it as far as aero and other mods till the rules for TT5 come out in late 2017. I am sure I am not the only one that is in this spot, when its all rolled out I think it will be great with possible larger fields and closer competition but the one by one roll out is putting people stuck between classes or ineligible for the one below.

 

We announced this many moons ago! This has been in the works for over a year now. If you were building for TTB, then the car should be good for ST4/TT4. If you look at the other forum thread that we have had for almost a year, currently, the plan would be for the next lower Dyno based class to have some aspect of car model included. It would not be an "open" class like ST1-4. Some models would be sent directly to ST4/TT4, or have such a high Mod Factor associated with them, that they functionally would if they were prepped for competition correctly. I would expect that the limit on Adjusted Wt/HP Ratio will be around that 14.5:1 region (maybe 15:1?), but with the added Mod Factors for Make/Model, you are correct that until we have that worked out, we won't know exactly which cars don't move to ST4/TT4. But, I would expect that just about all cars legal for PTD/TTD would be okay. I would expect that Most cars that are currently legal for PTC/TTC and make the 14.5:1 would be okay, with a few exceptions. I would expect that AWD cars, FR-S's, BRZ's, M3's, S2000's, to all have higher Mod Factors, pushing the ones currently in PTC toward ST4, but likely with those in PTD to stay in the lower classes. Still a work in progress....

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Greg G.
Greg, Regarding #7, There are a significant amount of BMW E36/46 race cars, via GTS 2/3, that have cage tie-in's to the rear subframe to help with known subframe issues. Might need to think about how to not exclude these cars.

 

-tony colicchio

TC Design

 

Section 7.3.2 C 1. of the 2016 TT rules indicate that sub-frame connectors and cage reinforcements through the floor pan are to be assessed at the discretion of the National Director. I never understood why these were allowed in GTS and not in ST. They don't offer a performance advantage, just prevent the weak BMW subframe from ripping out. What will the National Director assess in 2017?

So, its not an advantage to not have your subframe rip out?

 

Please send me the $20,000 engineer's study and all calculations showing that there is no performance advantage to having sub-frame connectors in a BMW that tie the cage to the subframe, through the floor. Please include comparisons to stock, basic cage, multiple different cage combinations, seam welded vs not, and include the different models of E36 and E46 cars that have different chassis (318's, two door, four door, etc.). Also, include the exact specifications of the proposed subframe connectors--or include a separate study for various proposals. Then, please send me the $50,000 study of at least 5 other highly used car models in ST for comparison. Once we have that data, and it shows that you are correct, and we know that what we intuitively think for most vehicles is an advantage based on past experience is incorrect, we will change the rule, and open it up for all models. For now, Appendix A of the ST Rules discusses permitted repair/prevention for E46's, and the allowance of the Sub-frame connectors through the floor for Mustangs and BMW E36 M3's for a -0.2 Mod Factor (an entire 50 lbs in ST4 for a 250 hp vehicle).

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