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Unread 02-20-2013, 06:02 PM
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Default Open Letter to the STAC/SEB: re - S197 Mustang move to STU

Open Letter to the STAC/SEB: re - S197 Mustang move to STU

There has been some good discussion of late about the competitiveness of the "pony cars" in the Street Touring class, specifically the S197 chassis 2005-2014 Mustangs in STX. Contrary to what you see showing up at National level events, since there is no ST class competitive for these cars to run in, there are quite a few owners of modern Camaros, Challengers and Mustangs that don't run with the SCCA, but can and do autocross and track their cars. Many if not most of these folks are "street tire" competitors and would likely jump at the chance to run in an ST autocross class, if they had a more level playing field.

This thread started this request: http://www.sccaforums.com/forums/for...94/scope/posts

These "pony cars" have been popular for 40+ years and are still being made by all three domestic automakers, in large numbers. V8 engines, rear wheel drive, somewhat simple suspensions, and a moderately sized chassis and a working man's price. It is a simple formula, but over the past 20 years the cars have gotten quite plump, but quite powerful. The latest iterations include the S197 chassis Mustang (2005-2014 models, 420 hp and 3600 pounds), the 5th gen Camaro (2010-2014, 426 hp and 3800 pounds), and the Dodge Challenger (2008-2013, 470 hp and 3900 pounds)

http://en.wikipedia.org/wiki/Ford_Mu..._generation%29 - Over 763,000 units sold from 2005-2011.
http://en.wikipedia.org/wiki/Chevrol..._generation%29 - Over 315,000 sold from 2009-2012.
http://en.wikipedia.org/wiki/Dodge_Challenger - Over 140,000 sold from 2008-2012.

These cars do have a place to race in Stock (FS) and Street Prepared (ESP), but there are all sorts of encroaching threats into these classes by lighter cars, almost all with more sophisticated suspensions or even AWD. But the only place they are allowed in Street Touring is in STX and STU, but they are classed based on their engine displacements. An unusual "5.0L" limit marks the split from STX to STU. In reality, the modern 5.0L Mustang GT (420 hp) makes almost the same horsepower as the 6.2L Camaro or the 6.4L in the Challenger.



Why does this matter? Shouldn't the modern 5.0L Mustang be in a more competitive class being in STX instead of STU? Well no, it comes down to a much less advantageous weight-to-tire ratio. As it is classed now, the modern S197 chassis Mustang is competing on a super skinny tire in STX, relative to its weight. It is limited to the same 265mm section width as a 2600 pound FR-S or a 2800 pound E36 328is. Sure, it "makes more power", but this is almost useless in Solo to begin with, as almost everyone knows that weight is FAR more important. Again - if they still allowed the 1900 pound Civics in STX, those would continue to dominate on 195mm tires. Light weight always wins.

Couple the antiquated solid-axle rear suspension to the too-skinny 265mm street tire with 3500-3600 curb weights, and these S197 Mustangs are only going to be turning tires into smoke and encouraging their drivers to find another form of motorsport that better meets their needs.



I know this first hand because we fought this battle for nearly two years (from 2010 to 2012), taking our 2011 Mustang to the STX class immediately after it was ordered and received. With this car we tested almost every 265mm 140+ UTQG tire available, and purchased multiple sets of tires and wheels that we tested head to head at our own test-n-tune events and at dozens of Solo events for two seasons. We spent many thousands of dollars on all of these tires and testing, only to be rewarded with frustration and poor placings. This wasn't just a casual autocross attempt, but a serious three driver, "no expense spared" build, with the resources of Vorshlag Motorsports behind it. We managed to knock out 150 pounds of weight from the originally 3600 pound car, used three different coilover suspensions including AST and Moton, made 430 whp in STX legal trim, all to no avail. It was a wasted effort, a failed test.

The car was undrivable.



It would overheat the rear tires within 20 seconds of a typical autocross run, no matter how it was driven by the three drivers. It just didn't have enough tire. We did test events where we ran in a higher gear and it was faster, lugging around at low RPMs and essentially limiting power. We had a custom ECM tune added that limited the electronic throttle opening based on RPMs, ignoring the throttle pedal inputs - again, to limit power. It was still a big mess.



Before the car was locked into STX, we ran our 2011 Mustang in the STU class for a couple of autocross events, increasing wheel size by an inch (to 18x10") and tire size by a mere 10mm (to a 275/40/18 Bridgestone RE-11). We were immediately rewarded by a much more drivable car, more competitive placings in class and a steep jump up in PAX placings. The drivers didn't just magically improve, but instead the car as a whole just worked SO much more effectively with the wider wheel and tire. This "class jump" option was over at the end of the 2011 racing season, so in the 2012 season we were back in STX jail, where we ran it until April 2012 - when we finally gave up and switched the car to ESP class, where the much wider tires this car needed were legal.

What I am getting to is this: we feel that the S197 Mustang should be moved to STU class, where the unlimited wheel width and 285mm width tire maximum is much more suited to a 3600 pound car.

Also, we think a slight bump in maximum tire width would benefit this and all other 3400+ pound stick axle cars now classed in STU. We think it would be best to limit the extra tire width only to the stick-axle cars, of which there are very few: the Camaro up to 2002 and the Mustangs up to 2014. How much wider? +10mm would be nice, as there are plenty of 295mm ST legal tires available. A bolder move would be to bump to 315mm tires, as we know these fit both the stick axle 1993-2002 Camaro/Firebirds and 2005-2014 Mustangs that would then fit in STU.


Left: 315mm tires under stock fenders from a 1998-2002 Firebird. Right: 315mm tires under stock fenders of our 2011 Mustang.

Will this make these cars instantly win the class? Of course not. Every year at Nationals since 2005 an AWD Turbo rally car has won STU class, except once.

After we left STX in the middle of the 2012 season, we jumped to ESP and went with a 315mm R compound tire. The car, virtually unchanged from our STX set-up, was instantly faster and more competitive. Our class placings and PAX placings jumped way up, and with only four months of preparation and a few National events in ESP, I managed a 2nd at a ProSolo, a 3rd at the Lincoln National Tour, a 4th at the Solo Nationals, and Amy won ESP-Ladies in the car at Solo Nationals. Again - this was almost our exact STX set-up, just with ESP appropriate wheels and tires and a few other set-up tweaks. I'm saying this to point out how poor the car performed in STX with even more testing, preparation, and the use of every available tire legal in that class.

This post is trying to show our proof that the S197 Mustang responds better to STU-legal wheel and tire widths, and beyond. And to ask, likely in vain, for a little "bump" in max tire width for the STU stick-axle cars, like the 4th gen Camaro/Firebird (already in STU, and also stick axle, and also very heavy, and can also swallow a 315mm tire under stock fenders) and the 5th gen Mustang. Give these cars a 315mm tire max and let them run in STU and I assure you that there will be new racers running there that were not in Solo before. Again, I think it is highly doubtful they would be a threat to the "status quo" cars this class is tailored to, but it would make these popular, powerful and heavy cars more fun to drive and put them closer to the top tier cars than they are now.

Proposed move: To STU class, 2005-2014 Mustang GT and Boss 302, 5.0L V8

Proposed wording for Stick Axle Bonus: All solid rear axle cars classed in STU shall have a maximum tire width of 315mm

Starting in model year 2015 (so, about one year from now) all new designs of the Mustang, Camaro and "Barracuda" will replace the current three domestic pony cars. New chassis, suspensions, drivetrains, and more. Each new model is rumored to be significantly smaller, lighter, and more powerful - and each will have more modern Independent Rear Suspensions. These "stick axle" benefits will likely not need to apply to these updated cars, of course.

Alternatively, to help ALL of the heavy RWD Pony Cars, maybe a more encompassing change is in order? Something like a sub-class within STU (STU Heavy? STU Pony Car?) could be called out with a few additional allowances over the standard STU allowances. This would only work with the new "assigned" style of ST classing that has been adopted.

I could see a call-out for the Pony cars with maybe additional tire, wheel and driveshaft allowances. This could be separate or combined with the additional stick-axle allowances, but seeing that some current, and all the 2015+ pony car models will feature IRS, I think it should be separated from the stick-axle allowances. The cars I see being included in the STU Heavy class would be the traditional pony cars that weighed 3300+ lbs in stock trim when new. 4th gen Camaro/Firebird, 5th gen Camaro, 2008+ Challenger, 2005-2014 Mustang.

If this STU Heavy sub-class is implemented we would ask for two different rules changes:

1. All of the heavy RWD V8 cars are allowed 140 treadwear tires up to 315 tread size.

2. Solid rear axle cars are allowed lower control arm relocation brackets bolted to axle. Removable axle differential covers may be swapped out for any purpose. Aftermarket one piece driveshafts of aluminum or carbon alloy steel may be substituted for the OEM driveshaft (exclude carbon driveshafts if you want to contain costs).

The extra aspects in point number two are probably wishful thinking, but if you don't ask you don't get them thinking about these things. The rear differential cover allowance is probably already coming in ESP (by 2014), but we want to make sure it happens in ST for solid axle cars as well. The relocation brackets are a simple, ~$100 fix that benefits almost all solid axle cars. When these cars are lowered the geometry on the rear Lower Control Arms goes to a very poor anti-squat condition, and these bolt-on brackets fix that. And the driveshafts on the modern pony cars are usually clunky, heavy two-piece units that are commonly replaced with aftermarket parts, and there are many solutions. Again - these are common modifications that fix real problems and each has many bolt-on options available.

Making changes like these would show that the SCCA actually pays attention to the both aftermarket and the owners of the cars they are trying to accommodate. That would be a new attitude, which I think the SCCA badly needs to adopt. There are just too many of these big Pony Cars sold to have so few show up in Street Touring classes. With some allowances like we have laid out, to help make up for their massive girth and added power over traditional STX/STU cars, maybe the SCCA could attract more of these cars and their owners to Solo.

Thank you,
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Unread 02-20-2013, 06:06 PM
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Default Re: Open Letter to the STAC/SEB: re - S197 Mustang move to STU

Submitted my letter on Feb 20, 2013 at 5:06 pm CST.

SEB Letter Tracking Number #10382
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Unread 06-18-2013, 11:11 AM
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Default Re: Open Letter to the STAC/SEB: re - S197 Mustang move to STU

And only a scant four months later this letter was reviewed:

Quote:
Terry Fair,
Your letter has been reviewed by the Street Touring committee, and a recommendation has been made to the SEB. The SEB will review your letter and the Street Touring committee's recommendation on their next conference call.
Four months.
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Unread 08-03-2013, 04:02 PM
jacksisco jacksisco is offline
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Default Re: Open Letter to the STAC/SEB: re - S197 Mustang move to STU

Hey Terry,

Don't know if you seen it yet but this proposal was featured in the august fastrack news on SCCA.com. Issue number 10437.

Maybe we can get some more support on this.

Thanks,
Scott
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Unread 08-05-2013, 11:15 AM
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Default Re: Open Letter to the STAC/SEB: re - S197 Mustang move to STU

Quote:
Originally Posted by jacksisco View Post
Hey Terry,

Don't know if you seen it yet but this proposal was featured in the august fastrack news on SCCA.com. Issue number 10437.

Maybe we can get some more support on this.

Thanks,
Scott
http://scca.cdn.racersites.com/prod/...k-aug-solo.pdf

While the STU move made it into FasTrack, there might be a long delay in this becoming the new class for S197 Mustangs (possibly 1/1/2015). There is much debate over this date and what applies to 2014 or 2014 in this FasTrack.

Quote:
Unless noted otherwise the effective date for all new rule, class, and listing change proposals herein is 1/1/2015
...and they snuck in some other cars into STU at the same time, such as:

Quote:
Proposed new listings added into STU (via Tech Bulletin):
Corvette (1997-2004) (Non-Z06, Non-FRC)
Genesis V6
Infiniti G37

Proposed 2014 re-classing (via listing change proposals, in conjunction with the above):
Ford Mustang (N/A)
Chevrolet Camaro (N/A)
Pontiac Firebird (N/A)
350Z non-NISMO
Infiniti G35
Genesis (2.0L Turbo) (2010-13)


Trying to compare the C5 Corvette to the McStrut AWD and RWD solid axle cars in STU is a *stretch*. The C5 Corvette has these features:
  • Aluminum double A-arm front suspension with a composite transverse spring
  • Aluminum 5 link IRS rear suspension with a composite transverse spring
  • A rear mounted transaxle and an aluminum mid-mounted V8
  • Rigid chassis consisting of hydroformed frame rails and a fully composite body
  • A fully flat bottom floor, made of Balsa wood and other composites
  • Room to fit the maximum STU 285mm tire and 11" wide wheels at all 4 corners
  • A curb weight of 3100 pounds in STU trim (proper exhaust headers, titanium Z06 exhaust, racing seats, light wheels and brakes)
  • Low roof height, slippery aerodynamic shape with a wide track width

Does this list of stats sound even remotely like any other car in Street Touring? No? Because it isn't at all like the cars in any Street Touring class. This is bringing the preverbal gun to a knife fight. I don't care that they outlawed the Z06 and FRC (that's just a simple addition down the road), this opens the door for more of the same.

And while these cars won't likely come to STU in large numbers, they will come, and they will destroy the pony cars and possibly even the existing STU winners. Even if they don't win, the PERCVEIVED EFFECT will be to keep the newly added S197 Mustangs and other RWD cars from even attempting to enter this class. Why? Because whenever you put a well balanced C5 Corvette up against these solid axle 3600 pound RWD cars in an autox setting, the C5 wins. Every time. You are comparing (initially) Super Stock then A Stock to F Stock cars.... it is hard to imagine a worse mismatch.

Discouraged,

Last edited by Fair!; 08-05-2013 at 11:47 AM.
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Unread 08-07-2013, 02:41 AM
jacksisco jacksisco is offline
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Default Re: Open Letter to the STAC/SEB: re - S197 Mustang move to STU

Thanks for the insight Terry. I guess I got a little too excited at the possibility of actually having a none stock class to run in and missed the corvette and the date.

You summed it up well.

Discouraging.
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