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"Model" bodywork for SCCA autocross

TeeLew

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The SCCA defines a car model like this:

model A group of cars of a given make which have virtually identical
bodies and chassis but are readily distinguished from other models
of the same make by virtue of a major difference in body appearance
and/or chassis design. The names by which the manufacturer designates
these groups have no bearing on this definition even though two
(2) groups may be designated identically.


The "Bodywork" rules for SCCA Street Touring are these:

F. Addition of spoilers, splitters, rear wings, bumper covers, valances, side
skirts, and non-functional scoops/vents is allowed provided that either:
1. It is a production part which is standard or optional equipment of a
US model of the vehicle. (“Model” is defined in Section 12.)

2. It is listed in the vehicle manufacturer’s US accessory catalog for that
vehicle for normal highway use. This does not allow for parts sold
through a manufacturer’s performance catalog (e.g., Ford Racing,
HPD, Mazdaspeed, Mopar Performance, Mugen, NISMO, SPT, TRD,
etc).
Parts must be installed as directed by the manufacturer. Exact replicas,
including weight, from alternate sources are also permitted.

When I read these rules, I think the Shelby Mustangs fit the description of "virtually identical bodies and chassis" almost perfectly. Yes, there are plenty of differences, but they're all in type, not kind. So, given that this is the case, It's probably OK to put a GT350 or 500 Hood, splitter, rear wing, etc on a Mustang, right? I'll check before going down this road, but do you all read the rule like I do?
 

SteveW

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I think you know what the intent is. Shelby's are excluded from ST, right? So, adding bodywork from those 'models' of the Mustang is really stretching the rules to use something that no GT or EB came with due to technicalities in the wording of the rulebook, at least at National Events. In my view in terms of a GT for example, the intent of those statements is to allow any spoilers, splitters, etc that a GT came within the range of PP, PP2, Base, Premium. Stuff like that.

There is a specific statement right above that section to give some leeway at Regional events, though:

In particular, some leeway in the area of bodywork allowances (e.g., wings/spoilers beyond those allowed in Section 14.2.F) is encouraged at SCCA® Regional Solo® events.
 

fatbillybob

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The fastest guys ending up at nationals are always bending the rules. It is the advantage that winners take. For SCCA clubracing the rules specifically state ballast be in the passenger side secured to the floor. A well sponsored continuous winner decided that on corvettes the ballast could be a heavy replacement tunnel plate smack in the center of the car at the lowest point in the chassis...the perfect place. We all started doing it instead of protesting it and all vettes got an advantage. Others kind of car racers did not know what we all were doing and somehow today it's still legal. I literally had a 150lb welded tunnel plate when the factory plate was a thin sheet of 14G steel! So you can ask your ? to the CRB or you can show up and see who protests you or joins who you. Rule making and rule bending is a long process. Sometimes there is not a shatstorm until Runoffs where I LOL when the top 5 spec miatas were DQ'ed for something everyone did and the 6th place car was declared the winner! I think that was the Daytona Runoffs.
 

TeeLew

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With the Miatas one year, when the Runoffs were at Laguna, the top 10 were disqualified for some engine tweek and 11th, which didn't have to go through tech, won.

Brian keeps telling me CAM, but, at least for the time being, my aim is Street Touring because the rules are a little restrictive. Those restrictions can provide advantages. There are some questions as to whether or not a Mustang can be competitive against the AWD contingent in Street Touring. I'm going to attempt at building the car to the rules & see what comes of it. Who is to say how optimized previous attempts really were?

I don't think aero is a big advantage in autocross, but it's probably enough of one to spend some time making sure it's addressed as well as possible, particularly if it allows you the opportunity to drop some weight in the process.

...And if it all turns brown & runs downhill, I'll go to CAM and be a happy little camper over there.
 
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fatbillybob

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With the Miatas one year, when the Runoffs were at Laguna, the top 10 were disqualified fit some engine tweek and 11th, which didn't have to go through tech, won.

Brian keeps telling me CAM, but, at least for the time being, my aim is Street Touring because the rules are a little restrictive. Those restrictions can provide advantages. There are some questions as to whether or not a Mustang can be competitive against the AWD contingent in Street Touring. I'm going to attempt at building the car to the rules & see what comes of it. Who is to say how optimized previous attempts really were?

I don't think aero is a big advantage in autocross, but it's probably enough of one to spend some time making sure it's addressed as well as possible, particularly if it allows you the opportunity to drop some weight in the process.

...And if it all turns brown & runs downhill, I'll go to CAM and be a happy little camper over there.
You are right I think it was 2014 Laguna. I can't remember all the details. Laguna was my 1st Runoffs done only because it was in California. All the hotshoes come out for Runoffs. I really like competing but wow is it expensive. It is a $10k week if I tow and a $15k week to another State. I won the "hard Charger" past the most cars in my class. Then I did it again the next year. Still with an under optimized car I'm just a mid-packer. In auto-X I really would not worry about aero. Once I had this fantastic Ferrari 348 racecar with wings and splitter and pretty decent undertray. Then the 1st time out with a non-aero stock body C5Z06 corvette we were already seconds faster per lap at Willow Springs. Yeah I guess in theory aero helps but really our cars are bricks through the air. A better driver with better mechanical set-up will bet home brew aero every time.
 

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With the Miatas one year, when the Runoffs were at Laguna, the top 10 were disqualified fit some engine tweek and 11th, which didn't have to go through tech, won.

Brian keeps telling me CAM, but, at least for the time being, my aim is Street Touring because the rules are a little restrictive. Those restrictions can provide advantages. There are some questions as to whether or not a Mustang can be competitive against the AWD contingent in Street Touring. I'm going to attempt at building the car to the rules & see what comes of it. Who is to say how optimized previous attempts really were?

I don't think aero is a big advantage in autocross, but it's probably enough of one to spend some time making sure it's addressed as well as possible, particularly if it allows you the opportunity to drop some weight in the process.

...And if it all turns brown & runs downhill, I'll go to CAM and be a happy little camper over there.
1) Aero isn't worth much, esp factory aero. Autox course designers target a max speed of ~65 mph, not 120mph. That steep 60’ spoiler on that prepared car with the big splitter isn't helping nearly as much as the weight loss from it's stripped out interior.

2) Just run CAM. STU is more restrictive, but those provided advantages entirely benefit the lighter, lower center of gravity AWD cars and work against the heavier larger Mustang with a rubber bushing rear suspension. We're talking only 5/1000 difference in PAX between STU and CAM, so the decision should be clear. My FS friend is jumping to CAM instead of STU when he slaps on a 2nd swaybar just for the competition - its more fun to run against similar pony cars that wonder what-if and run against Subarus.

The pony cars just don't have a good 'street touring' class right now. It used to be STP, but we lost that. It didn't allow for few of the 'typical' pony car mods so it died relatively hasty death. I get the reluctance to go to a nearly open class like CAM. You're basically assured to go up against a car that is way more built for the class then you are at some level of competition, but FWIW, at least regionally here in Texas its only been nothing but fun. There are some ex-modified cars that slapped on 200 TW tires and added some carpet for interior and upholstery, but their drivers still make mistakes. Modified classes never attracted the smartest or most skilled of drivers :p
 

TeeLew

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I think you know what the intent is. Shelby's are excluded from ST, right?
I don't care give a Frenchman's F about intent. I'm building to a rulebook and want to identify possible advantages.
 

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Isn't there a proposal out to ovehaul STU like completely ? I vaguely recall it from couple of fast tracks ago.... OP - you may want to check it out before you invest in your build, wings and such....
Current STU stage seemed to be little stale / dead, car I consistently have seen on national events was Nortons Fiata but he didn't have much competition there. Nats participants list shows half and half AWD boost buggies and RWD BMWs - E92 and E46s.
 

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1) Aero isn't worth much, esp factory aero. Autox course designers target a max speed of ~65 mph, not 120mph. That steep 60’ spoiler on that prepared car with the big splitter isn't helping nearly as much as the weight loss from it's stripped out interior.

2) Just run CAM. STU is more restrictive, but those provided advantages entirely benefit the lighter, lower center of gravity AWD cars and work against the heavier larger Mustang with a rubber bushing rear suspension. We're talking only 5/1000 difference in PAX between STU and CAM, so the decision should be clear. My FS friend is jumping to CAM instead of STU when he slaps on a 2nd swaybar just for the competition - its more fun to run against similar pony cars that wonder what-if and run against Subarus.

The pony cars just don't have a good 'street touring' class right now. It used to be STP, but we lost that. It didn't allow for few of the 'typical' pony car mods so it died relatively hasty death. I get the reluctance to go to a nearly open class like CAM. You're basically assured to go up against a car that is way more built for the class then you are at some level of competition, but FWIW, at least regionally here in Texas its only been nothing but fun. There are some ex-modified cars that slapped on 200 TW tires and added some carpet for interior and upholstery, but their drivers still make mistakes. Modified classes never attracted the smartest or most skilled of drivers :p
All of this. There's also that very, very few cars nationally are prepared as deep as the rulebook allows. The vast, vast majority are running bolt ons for power, coilovers, bars and sphericals everywhere on 11"+ wheels.
 

kz

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#28321 Make STU Great Again! <- April 2020 Fast Track.
 

Grintch

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I don't care give a Frenchman's F about intent. I'm building to a rulebook and want to identify possible advantages.
The general guidance I always got was you were OK if the items were from the same eligibility line.
"Mustang GT (excl. Shelby versions & Boss 302) (2005-20)"
And the GT350 is explicitly excluded.

The hood is not allowed by section F. The front bodywork of a GT350 is different (the GT500 only more so), so you can almost guarantee the splitter won't just bolt on (as required).
Your good with the PP2 parts. GT350 /GT350R rear wing is probably over the line, splitter & hood, well over the line.

Plus OEM aero isn't going to make much difference at autocross speeds.
 

thasuperdude

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You can not run any body part that didn't come as an option on your exact car. Or take them off for that matter. I ran STU for years (ran the TECH inspection for 12+) locally and nationally. You can go up or down in wheel diameter, but not wider. If you're looking to cheat, swop out the heavy ass flywheel. Then get some RPF-1's in 18" x 9.5" and RE-11s. You'll shed massive amounts of weight in the right places. Another way driver cheat is by swopping out the lower control arms for the GT350s +
 

kz

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You can not run any body part that didn't come as an option on your exact car. Or take them off for that matter. I ran STU for years (ran the TECH inspection for 12+) locally and nationally. You can go up or down in wheel diameter, but not wider. If you're looking to cheat, swop out the heavy ass flywheel. Then get some RPF-1's in 18" x 9.5" and RE-11s. You'll shed massive amounts of weight in the right places. Another way driver cheat is by swopping out the lower control arms for the GT350s +
Feels like a lot of work to lose by second or two to Subaru or some Volkswagen. People also started building E46 and E92 BMWs for STU, if the proposal goes through then the new ones will be eligible (F80 ?)
 

thasuperdude

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I left my STU WRX for an F-Street E92. It was soooo much better than the S550 is. I've come to the realization that this is a mountain road champion, but not so much an autocross tool.

My wish list would be a smaller steering wheel, lighter flywheel and a MUCH faster steering rack. It's too slow for a well paced slalom.

Oh and a lower gear set OR higher rear end gear. 4.09 at a minimum.
 

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