OS Giken vs Torsen

[RedRocks]

Grant thanks for the depth on the Torsen. I mainly autocross with a handful of trackdays a year so a good compromise between the two is what I’m shooting for. Sounds like the Boss T2R might fit the description. I know you run a Torsen of some flavor in your car. Which bias is it? Also how much power is Axstang putting down?

There’s a local guy here that specializes in OSG setup so I was gonna have him go through mine if I went that route. I think I have ruled it out honestly though. As Speedboosted said the couple tenths faster it would be aren’t really worth the extra $1000 .

I don’t do any drag so the worst shockload the diff will get is R Comp launches at autocross. So it’s Torsen 2.7/4.0 vs. TrueTrac now...

 

[Grant 302]

I have the stock 2.7:1 bias Torsen in the Boss. Traction lok in the GT. Can't say I know Axstang.

 

[RedRocks]

I have the stock 2.7:1 bias Torsen in the Boss. Traction lok in the GT. Can't say I know Axstang.

Ah I think I’m getting you confused with another Grant out in Georgia that has a Youtube channel called SpectroRacing. He also has a Torsen equipped Mustang.

 

[Norm Peterson]

Spotting an assembled "R" should be easy and see the Thrust Plate differences:
https://torsen.com/product/ford-8-8-t2r/

or
https://torsen.com/product/ford-8-8-31-tooth-spline-t2r/#


T-2:
https://torsen.com/product/ford-88-31-tooth-t2/#

Do these Torsen differentials allow "regular 2008 GT axles" to be used directly? I think I'm in for a ring & pinion as it is, and I'd consider stepping up to a Torsen while I'm at it . . . as long as doing so doesn't require extra modification to work.


Norm

 

[ArizonaBOSS]

@Norm Peterson I'm not sure if there is any fundamental difference in the 8.8 rear throughout the life of the S197--to my knowledge they are all 31-spline axle shafts with the same lengths etc. So it should fit any V8 S197 rear end.

 

[RedRocks]

Yeah stock 31 spline axles should work no problem.

 

[Grant 302]

Agree with the guys above. Only an issue if you can't get the right spline count. MM sells both 28 and 31 IIRC, but I think everything went 31 spline after the SN95.

 

[Norm Peterson]

Thanks, guys.

What I'm not seeing in the pictures is a clear indication of where the U-washers (aka C-clips?) would go. I've done a couple of differential changes on a different car and had to replace axle seals on this one, so I've at least seen the inside of an axle.


Norm

 

[Grant 302]

They'd come out after the thrust block or go in before it:
http://www.maximummotorsports.com/assets/install/pdf/drivetrain_clutch/Torsen_instructions.pdf

 

[Norm Peterson]

Thanks.

On to deciding which one to get. I'm thinking that having only a normally-aspirated 4.6L (and no more autocrossing) might mean less need for a big TBR.


Norm

 

[VoodooBoss]

On the FB page Billy Johnson gave a strong recommendation for the Eaton True Trac. I know nothing about the different diffs but wanted to pass this along.

 

[Norm Peterson]

Thanks. Anything on FB is likely to be inaccessible, so I'd have never stumbled across it on my own.


Norm

 

[VoodooBoss]

You're welcome. I had to dig deep for it but I found it.

 

[Grant 302]

Forgot to add earlier, I believe the '13-'14 GT500s (and GT TPs) also got the same T-2R. So at least Ford tested it at higher s/c power levels.

 

[Grant 302]

Thanks.

On to deciding which one to get. I'm thinking that having only a normally-aspirated 4.6L (and no more autocrossing) might mean less need for a big TBR.


Norm

I think the choice, then, would come down to tires you use. I think the higher bias makes more sense toward more grip with larger and/or stickier tires. The N/A FR500S uses the 4.0 bias unit originally with 245 R1 slicks IIRC. It *should* be faster as you approach tire lifting conditions. I don't think you'd go wrong with either.

 

[Norm Peterson]

Any thoughts about TBR and wet track days?




Norm

 

[Grant 302]

More of a guess, but lower bias since *much* lower grip limits.

 

[Norm Peterson]

Guesses with a thought process are entirely welcome.

In that wet picture the Trac-lok probably wasn't capable of biasing all that much torque, but the car could be danced around neutral with just the throttle.

Norm

 

[cgornowich]

Norm,

I pulled a GT500 rear end from a salvage yard and rebuilt it with a Torsen T2R (4.0 bias) and installed 3.73 gears. The stock axles worked on mine.

 

[RedRocks]

http://stangsunited.com/showthread.php?4777-Torsen-T2R-Recommendations

Torsen recommended the 2.7 to this guy that had a GT500 based on his power level. This was back in 2011 though so I think that was before the latest version of the T2R. Funny because in the email the Torsen rep recommends that he not use the T2R if he is on slicks despite the fact that the T2R was developed for a race car on slicks (Fr500). I think all things considered the 2.7 Torsen is gonna be the best for my car. It has a slightly higher TBR than the TrueTrac and is more reliable than the 4.0 unit for a powerful car.