2015 irs

[rrg9946]

The 2015 Mustang’s new IRS carries upgraded rear-axle hardware. Dimensional and metallurgical torque-density improvements are said to give these assemblies the strength of a 9.75-inch diff, while still retaining the 8.8-inch ring gear diameter. Ford apparently internally refers to this as the “Super 8.8.” The diff carrier itself is made of iron on manual-gearbox cars, and aluminum (to save a little weight) with automatics. Oh, and all 2015 Mustangs will come standard with limited-slip diffs; with a Torsen being part of the GT Performance Package.



This might give an insight on how the rear end will handle drag strip duty.

 

[sunburned]

Jeep did it with the JK, created a tougher version of the Dana 44. Of course, they actually made the gearset bigger, as well as the entire axle assembly. Hope this holds up for Ford. I know the 8.8 is strong, but isn't it time to step it up a notch, especially with stuff like the GT500 putting out damn near 700hp?

 

[DMassey]

the diff and ring & pinion were the last things I was worried about.

 

[DHG1078]

Jeep did it with the JK, created a tougher version of the Dana 44. Of course, they actually made the gearset bigger, as well as the entire axle assembly. Hope this holds up for Ford. I know the 8.8 is strong, but isn't it time to step it up a notch, especially with stuff like the GT500 putting out damn near 700hp?

Are people with over 700 rwhp breaking them (serious question)? If not then I don't really see a reason to. It would cost us more money, probably add weight, and add zero benefits.

 

[specizripn]

I think the concern is more traction related, and then once you get traction, half shaft related... The Cobras were notorious for wheel hopping and snapping a half shaft...

 

[04svtsnke]

I think the concern is more traction related, and then once you get traction, half shaft related... The Cobras were notorious for wheel hopping and snapping a half shaft...

This isn't 2004. Don't get me wrong, there will be half shafts breaking, but I'm sure ford has went over and above to make sure this wasn't a failure like the stock irs in the cobras.

 

[kino]

Back then the 03-04 cobras were using a makeshift irs on a platform that never was intended on using an irs. I think the irs won't be the issue. Course there will be a learning curve buts that's to be expected.

 

[steeltoe]

Jeep did it with the JK, created a tougher version of the Dana 44. Of course, they actually made the gearset bigger, as well as the entire axle assembly. Hope this holds up for Ford. I know the 8.8 is strong, but isn't it time to step it up a notch, especially with stuff like the GT500 putting out damn near 700hp?

The 9.75 was in the Lightning and most lightning guys don't even touch the rear end other then to change gears and/or diff.

 

[Tob]

Ford engineers saw a need to upgrade. We should be thankful not only for the fact that they upgraded the internals but for the reason that necessitated the change in the first place.

 

[twistedneck]

Ford engineers saw a need to upgrade. We should be thankful not only for the fact that they upgraded the internals but for the reason that necessitated the change in the first place.

yea because its gets hotter than hell and needs to be larger to dissipate the heat in the IRS. IMO there is not a torque reason for this, the 8.8 was never weak.. at least I don't remember seeing many broken units. I bet its also a structural member now.

 

[SID297]

All I know is that I'm looking forward to stretching mine's legs out at CMP.

 

[po-po 5.0]

The 8.8 diff was never the problem, it was the c clip axles. Obviously, c clips are non-issue in the IRS.

 

[Charlington]

2015 Mustang IRS is a huge improvement.

Heavy Duty Rigid Explorer style Diff Cover
Moved Coil Sprngs behind the Axles to help kill wheelhop
Lincoln style IRS Subframe for easy install/removal/stability
Easy Access Drain Plug
Massive Control Arms

I'll take a Dozen!

 

[SonicDTR]

Jeep did it with the JK, created a tougher version of the Dana 44. Of course, they actually made the gearset bigger, as well as the entire axle assembly. Hope this holds up for Ford. I know the 8.8 is strong, but isn't it time to step it up a notch, especially with stuff like the GT500 putting out damn near 700hp?

Same thing with a Dana "Super" 60...

Good to see the new IRS appearing quite beefy, look forward to seeing real world results!

 

[dom418]

This isn't 2004. Don't get me wrong, there will be half shafts breaking, but I'm sure ford has went over and above to make sure this wasn't a failure like the stock irs in the cobras.

Exactly! Why do people assume that ford has made zero advancements since 2004? The new stang wont have the same issues as the Terminator .

 

[SID297]

Exactly! Why do people assume that ford has made zero advancements since 2004? The new stang wont have the same issues as the Terminator .

It's just ignorance to think it won't be improved vs. a 15+ year old design in a chassis from the late 70's.

 

[rrg9946]

Does anyone have any info on the upgraded half shafts that FRPP used to make the 1/4 hits?
Price
Part number
Threshold
Diameter

 

[SID297]

I've seen them. They are entirely new pieces exclusive to FRPP.