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Rear sway bar size on non Recaro/Torsen Boss

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Curious to know what size REAR sway bar came on the 2012 Boss 302 that had the standard seats and rear diff. Thanks.
 
Thanks I saw that also. I ask the question because on the Boss 302 video, one of the engineers states that they are able to run one of the biggest rear sway bars because of the Torsen. He says with the standard clutch diff this amount of bar will lift the inside tire and fry it. I am curious to know what size was used on the Boss' without the Torsen. Would it be the 24mm the was used on the GT as stated in the sticky thread? That doesn't seem to be that big of a difference....
I am removing my torsen for a clutch diff.....I want to drag race my '12 boss 302 car. I hear that the Torsen is not good for the drag strip.
I may just remove the rear sway bar in the process.
 

Norm Peterson

Corner Barstool Sitter
939
712
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
Have you looked into the Eaton/Detroit Truetrac? It's supposedly a good bit stronger in a dragstrip environment. IIRC, the bias ratio (3.5-ish) is a little higher than the Boss Torsen (2.7).

On edit, I'm not sure that you want to reduce rear roll stiffness for the dragstrip no matter what you put inside the pumpkin - it's what "re-plants" the RR tire against the driveshaft torque reaction inside the pumpkin planting the LR and unloading the RR. It accomplishes this by attracting more of the engine torque reaction from the other end of the car by carrying it back through the chassis. It's a relative stiffness thing, where more of the load goes to where more of the stiffness is.

While a limited slip diff or a locker will mitigate or eliminate the one-tire spin, equalizing the vertical loading between the rear tires does increase the total grip for acceleration. It's why the "antiroll bars" available to the drag race folks are so huge. The only reason I can think of where you wouldn't use a rear bar at the dragstrip would be if you were running a ladder bar car (where the ladder bars and the axle combine to effectively create an even more rigid antiroll bar.


Norm
 
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6,363
8,188
I agree with the above statement wholeheartedly, in a drag race environment, I would think a massive sway bar and a spool would be the way to go. At one time I was looking to contract out to a drag racer that needed his CJ towed everywhere, I met them at a drag strip, they had a bunch of Ford drag cars there, all on spools.
I think this is what you're looking for, although I would get it from UPR

SWbNuwpl.jpg
 
6,363
8,188
Thanks I saw that also. I ask the question because on the Boss 302 video, one of the engineers states that they are able to run one of the biggest rear sway bars because of the Torsen. He says with the standard clutch diff this amount of bar will lift the inside tire and fry it. I am curious to know what size was used on the Boss' without the Torsen. Would it be the 24mm the was used on the GT as stated in the sticky thread? That doesn't seem to be that big of a difference....
I am removing my torsen for a clutch diff.....I want to drag race my '12 boss 302 car. I hear that the Torsen is not good for the drag strip.
I may just remove the rear sway bar in the process.

Just the opposite, the Torsen gets the spaghetti string rear bar
 

Grant 302

basic and well known psychic
Thanks I saw that also. I ask the question because on the Boss 302 video, one of the engineers states that they are able to run one of the biggest rear sway bars because of the Torsen. He says with the standard clutch diff this amount of bar will lift the inside tire and fry it. I am curious to know what size was used on the Boss' without the Torsen. Would it be the 24mm the was used on the GT as stated in the sticky thread? That doesn't seem to be that big of a difference....
I am removing my torsen for a clutch diff.....I want to drag race my '12 boss 302 car. I hear that the Torsen is not good for the drag strip.
I may just remove the rear sway bar in the process.
I’d leave the stock rear bar. Lots of good suggestions above. Depends on what tire you plan on running for more specific recommendations.

Trailing arms and geometry changes would be at the top of my list for upgrades.

It’s my OPINION that the internet is wrong about the suitability of the Torsen for drag racing. Would I choose one? No. But I also wouldn’t bother taking one out unless there’s a good reason to do so. Selling it to install another diff makes sense, but if it’s not only drag or still sees a fair amount of street time, maybe reconsider. Taller gears are probably more important. Or whatever the right gear is for the tire and power you plan to have. The internet usually fails to point out that the Boss diffs are T-2Rs and are pretty durable.
 

Norm Peterson

Corner Barstool Sitter
939
712
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
I managed to overlook the other side of the roll stiffness coin before - there's more than one reason that drag racers remove the front sta-bar. It's not just to reduce front weight, though that's obviously another little step in the right direction. Taking away front roll stiffness achieves a similar effect as adding rear roll stiffness, biasing the roll resistance to become less forward/more rearward.

Needless to say, there's likely to be some changes in the car's handling from either modification.


Norm
 
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Grant 302

basic and well known psychic
Agreed. Meant to mention about also removing or unhooking one of the front bar links. Helps with load and weight transfer if looking at the two separately.
 

Dave_W

Cones - not just for ice cream
986
1,277
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
The internet usually fails to point out that the Boss diffs are T-2Rs and are pretty durable.
From what I can tell, though, the Boss Torsen is a T-2R with the new Equvex II gearing and Split Gear tech that according to Torsen lets them tune the TBR to each application. https://torsen.com/works-part-2/ The Googles finds that the Boss T-2R TBR is 2.7:1 while the FR500 T-2R is 4:1. https://www.allfordmustangs.com/threads/advantage-of-torsen.320821/post-3173034
Actually, doing some part number matching, the 31-spline T2-R sold by Maximum Motorsports is Torsen 975420-0200AF, which Torsen lists as TBR 4:1 on drive and 3:1 on coast. https://torsen.com/product/ford-8-8-31-tooth-spline-t2r/ They also list two T2-Rs for the S550, both with only 3:1 TBR on drive and 2:1 on coast; the difference appears to be a stronger billet case for higher gearing applications. I believe the Boss-specifiic T2-R also uses a stronger case, which could be why it costs more than the FR500 version.
 

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