Cast Iron Diff Housings don't just belong on Manual Trans Cars: Broken Aluminum Diff

[BMR Tech]

I had a long weekend of breaking parts at the track this weekend at NMRA Bowling Green World Finals. :mj:

First pass off the trailer - heard a very loud snap right on the launch. I snapped the ears right off the diff housing, on the front side.

 

[Dcrypter]

Was that because of stiffer bushing and the case not being designed to take the extra abuse?

 

[blackbeast12]

Would this Dss 9inch solve this issue:

http://www.allfordmustangs.com/foru...s/776993-dss-new-irs-9-diff-2015-mustang.html

 

[P49Y-CY]

dayum

 

[Tob]

Those ears look extremely small with woefully inadequate ribbing. The fact they were aluminum...this was destined.

 

[SID297]

I saw it in person. It was ugly.

 

[Tob]

Ford, no doubt, saw this when running different FEA scenarios (when different constraints were placed at various bushing locations) with simulated shock levels. It'll be interesting to see if there are any changes made to this area throughout the S550 production run whether on the iron or aluminum carrier. And yes, we are talking about a level of abuse that the OEM's don't normally cater their designs to. But rear axle "robustness" has been fairly synonymous with the corporate offerings from Ford. A Super 8.8 should indeed be super.

 

[BAD GT]

Can you fab some kind of brace to connect these two points to the diff cover or something to stiffen it up somehow? Or do you have another plan?

 

[SID297]

I'm really interested to see what the iron dif can handle.

 

[esacteksab]

Definitely interested in the outcome. One turbo car went 1.37 60' and another turbo car went 1.33 60' -- so I'm curious if this was just a fluke, or if this car had more passes on it and the other cars are on borrowed time. While a 9" IRS swap is more expensive than just putting half shafts in the car, I want to believe it is stronger all around and worth the peace of mind.

 

[blackbeast12]

Yeah but since the break was so catastrophic it will always be in the back of your mind when you go to launch. The dss 9 inch is a cast iron housing with aluminum gear housing . It mounts to its frame on the cast side iron of the
housing , this should solve the problem!

 

[SID297]

Definitely interested in the outcome. One turbo car went 1.37 60' and another turbo car went 1.33 60' -- so I'm curious if this was just a fluke, or if this car had more passes on it and the other cars are on borrowed time. While a 9" IRS swap is more expensive than just putting half shafts in the car, I want to believe it is stronger all around and worth the peace of mind.

Turbos are way easier on the drivetrain than an equivalently powered PD blower. The blower car hits much harder with more torque down low.

 

[DSG2003SVT]

Kelly, I can't seem to find the thread about it, but what's the weight difference in the iron housing and the aluminum one?

 

[boardkat]

it was 23lbs difference (85 vs. 108) when i compared my housings (3.73 w/ Torsen in iron with stock factory fluid fill vs. 3.55 w/ OSG in aluminum with 2QT of OSG 80W250)

fwiw, no issues (yet) after a season of autox runs (including several pro solos) in near-full prep ESP trim with two nationally competitive drivers that don't baby the car. i carry my stock housing with me to out of town events waiting for the failure though

 

[DSG2003SVT]

Cast Iron Diff Housings don't just belong on Manual Trans Cars: Broken Alumin...

Thank you for the information, sir. Something tells me that NA torque levels and no launches on slicks will keep the aluminum housing from being an issue.

 

[SID297]

That's a significant weight difference, but it's still better than breaking at the track.

 

[402]

Was this with completely stock bushings?

 

[Sir Nate 3000]

^^
?

 

[KAHBOOM]

https://www.steeda.com/ford-s550-mustang-irs-aluminum-differential-housing-15-17-gt.html has anyone tried this housing yet for track use. It's supposed to be an upgrade for auto cast housing, while still aluminum it's supposed to be able to stand up to the abuse of FI applications and track use.