The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

2011 V6 6-Speed Mustang for Endurance Racing

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Do you have the rulebook for the race series you want to participate in? Would be an interesting read. I wonder if since it's a Ford part that came in OEM vehicles if there's a loophole on what 'stock' is :)

Yep, that's the issue. The rules say we can use the diff if it was available for the year/make/model or generation of the car, but it excludes the Boss/GT500/etc since it's a specialty/high-performance model.

The gear rules are a similar story. We can use any factory-offered ratio for our year/make/model or generation, excluding specialty models like Boss 302. We had an idea last night that would possibly allow us to use 3.73s...we think those were offered in the 05-09 Mustang GT, which would make them allowed for our car (same generation). But we think they're too low for the job anyway.
 
We can use any factory-offered ratio for our year/make/model or generation, excluding specialty models like Boss 302.
2011 GT was offered standard with 3.31s, but 3.55s or 3.73s were a factory option on manual transmission Mustangs.

1675105032147.png

Another thing to keep in mind is that the 2013-2014 Mustang GT had the Track Pack option, which from factory included the Boss 302 Torsen. If you're allowed 'regular non-special version' parts from your generation, that covers a helical type differential since the GT is neither a Boss, Shelby, etc.

1675105924754.png

So I wouldn't see the problem based on your explanation of the rules in running any GT rear gear (3.31, 3.55, or 3.73) with the Boss Torsen you said you already have. You may even be able to use the automatic's 3.15 rear gear ratio if it worked better with your V6 transmission for the specific track you were looking to run at.
 
Last edited:
2011 GT was offered standard with 3.31s, but 3.55s or 3.73s were a factory option on manual transmission Mustangs.

View attachment 83490

Another thing to keep in mind is that the 2013-2014 Mustang GT had the Track Pack option, which from factory included the Boss 302 Torsen. If you're allowed 'regular non-special version' parts from your generation, that covers a helical type differential since the GT is neither a Boss, Shelby, etc.

View attachment 83491

So I wouldn't see the problem based on your explanation of the rules in running any GT rear gear (3.31, 3.55, or 3.73) with the Boss Torsen you said you already have. You may even be able to use the automatic's 3.15 rear gear ratio if it worked better with your V6 transmission for the specific track you were looking to run at.

This is where the rules get confusing. I don't think we can use parts from cars that are not on the allowed list. But the rule doesn't really say that.

Here's the full Champ rule so that I'm not just giving you half of it or my (possibly flawed) interpretation:
"Differential swap: 25pts for any diff not originally available for your year, make, and model or chassis generation (excluding specialty high performance models not listed on the VPI table). Includes axles and CV’s."

"Final drive ratio is open to all factory offered ratios for that body style or chassis generation. If that body style or chassis generation was offered from the factory with an LSD, its use is permitted. Specialty high performance models not listed on the VPI table are excluded."


2011-14 Mustang GTs are not on the approved list. So I was thinking the only "factory option" parts we could run are:
-2005-09 Base or GT
-2011-2014 Base

From what we found last night, the 05-09 GT had a 3.73 option. So it's possible to run that; it's the same generation and on the allowed list. But the Torsen...I'm thinking it's a no-go, since that "Track Package" might be a specialty high-performance model and not on the VPI list.
 
I'm thinking it's a no-go, since that "Track Package" might be a specialty high-performance model and not on the VPI list.
Here's where the nuance could potentially come in. The Mustang GT is a model (could be further refined by saying that GT is a trim of the Mustang model, but that would open up the Boss 302 as being a trim as well). The Track Package is an option on that model/chassis and is included as a factory part on your chassis generation. I don't think anyone would call a GT a 'specialty' model, unless you're saying that a Mustang GT couldn't run in the same series you are? Is there a sanctioning body you can reach out to for clarification on the verbiage?

The Brembo Brake Package was the track-package-by-another-name in 2011 and 2012. It had the upgraded 14" 4-piston brakes (which the Boss-to-be later used in 2012) and a retuned suspension with different springs and dampers. They added additional parts-bin features in the 2013-2014 Track Package as carryovers from the Boss. I personally think based on the limited information I've seen so far that it would allow you to run all of those components that were not exclusively offered in the Boss 302, including better 4-piston calipers and the helical diff.
 
Last edited:

Bill Pemberton

0ld Ford Automotive Racing Terror
8,425
8,355
Exp. Type
Time Attack
Exp. Level
20+ Years
Blair, Nebraska
Trying to out think the rules usually ends up with one getting protested since there is almost always a statement noting that if an option is not specifically included, adding it something you don't find specifically excluded is ok. Rule of thumb is if looking for gray areas, they have been viewed by many so often the " Rules Committee " often just comes down to whether an item on a approved list --- not on the list, you are better off skipping any rationalizations on why you can use your secretly found mod.
 
Here's where the nuance could potentially come in. The Mustang GT is a model (could be further refined by saying that GT is a trim of the Mustang model, but that would open up the Boss 302 as being a trim as well). The Track Package is an option on that model/chassis and is included as a factory part on your chassis generation. I don't think anyone would call a GT a 'specialty' model, unless you're saying that a Mustang GT couldn't run in the same series you are? Is there a sanctioning body you can reach out to for clarification on the verbiage?

The Brembo Brake Package was the track-package-by-another-name in 2011 and 2012. It had the upgraded 14" 4-piston brakes (which the Boss-to-be later used in 2012) and a retuned suspension with different springs and dampers. They added additional parts-bin features in the 2013-2014 Track Package as carryovers from the Boss. I personally think based on the limited information I've seen so far that it would allow you to run all of those components that were not exclusively offered in the Boss 302, including better 4-piston calipers and the helical diff.
Yes, that's the case here. Except 05-09 GTs can run with us, 2010+ GTs can't (yet anyway).
Trying to out think the rules usually ends up with one getting protested since there is almost always a statement noting that if an option is not specifically included, adding it something you don't find specifically excluded is ok. Rule of thumb is if looking for gray areas, they have been viewed by many so often the " Rules Committee " often just comes down to whether an item on a approved list --- not on the list, you are better off skipping any rationalizations on why you can use your secretly found mod.
That is also correct. They do have that in there.
 

TMO Supporting Vendors

Top