aluminum diff versus steel diff

[Tommy V]

Has anyone with a high power stick car 650 plus whp tried running the aluminum diff from the auto and if yes hows it holding up?

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[TNcoupe]

Has anyone with a high power stick car 650 plus whp tried running the aluminum diff from the auto and if yes hows it holding up?

Pretty sure @BMR Tech blew one to bits not long after the car hit the strip. Can't remember if it was the aluminum or cast iron one though.

 

[BMR Tech]

I would never ever recommend an aluminum housing on a stick shift high powered car.

This was mine with an automatic, and about 800rwhp.

 

[BMR Tech]

Here is one that broke locally on a DYNO, not even the track.....

 

[BMR Tech]

Here is another one that bent. It was on it's way out, no doubt.

 

[Tommy V]

Well ok then i guess that answers that question.Now have to decide if its cheaper to just buy another steel diff or put gears in my torsion??

 

[TNcoupe]

Loaded cast iron diff with a 3.55 from LMR is $899. My guess is it would be close to the same price to buy gears and have someone install them if you can't setup a rear diff on your own. I know the straight axle 8.8s require a crazy amount of torque on the pinion nut and have to have 15-17in lbs (IIRC) preload on the pinion bearings to get them right. It was tough to get them at the correct preload and keep everything from moving around while torquing the nut. If you have that much RWHP are you going to do half shafts too? I would while I was in there if you havent already.

 

[Cobra Jet]

Curious...

Why did Ford opt to use an aluminum cast diff housing on the 6R80 as opposed to the iron cast diff housing used with the MT82?

I'm also surprised that the diff "ears" are so frail or small, as just by looking at the design those look like immediate points of failure. Has any Vendor considered marketing a beefed up rear diff housing?

Does the Ford SUV line utilizing rear IRS have a stronger diff housing?

 

[TNcoupe]

Curious...

Why did Ford opt to use an aluminum cast diff housing on the 6R80 as opposed to the iron cast diff housing used with the MT82?

I'm also surprised that the diff "ears" are so frail or small, as just by looking at the design those look like immediate points of failure. Has any Vendor considered marketing a beefed up rear diff housing?

Does the Ford SUV line utilizing rear IRS have a stronger diff housing?

I wouldnt think any of the SUVs would have a stronger diff housing that the Mustang. They probably dont have drivers that are quite as throttle happy and you dont see any Expeditions with 800 whp. Someone on here was installing a 9" Ford center section into the IRS on a car the was Hellion twin turboed I believe. That might be the ultimate swap considering gears and options are almost endless for the 9" Ford.

 

[BMR Tech]

I was the first person to install and use a 9" IRS in the S550.

See pics.

 

[BMR Tech]

I went 1.2 sixties with the stock IRS and FRPP Shafts and BMR Lockouts.

But I had to repair parts after every trip to the track at that point.

So I swapped to all solid BMR stuff with the GForce Kit, and now the car goes 1.2s and stays quiet and doesnt break parts.

Well worth it IMO.

 

[MRose]

Why did Ford opt to use an aluminum cast diff housing on the 6R80 as opposed to the iron cast diff housing used with the MT82?

Probably to help offset the weight gain of the automatic.

 

[Tommy V]

Loaded cast iron diff with a 3.55 from LMR is $899. My guess is it would be close to the same price to buy gears and have someone install them if you can't setup a rear diff on your own. I know the straight axle 8.8s require a crazy amount of torque on the pinion nut and have to have 15-17in lbs (IIRC) preload on the pinion bearings to get them right. It was tough to get them at the correct preload and keep everything from moving around while torquing the nut. If you have that much RWHP are you going to do half shafts too? I would while I was in there if you havent already.

Yea i hear that,ive done 8.8 before but no longer have the dial indicators and crap to set one up plus like u said they are a pain in the ass.Also not sure how much different the torsion is to the trac loc.Iknow one has clutches and one has gears for the limited slip.I did the halfshafts awhile back,i knew they were a no go with radials lol.

 

[whatsup62]

I'm thinking you want to lean toward the 3.31's instead of the 3.55's with the MT82. smokinzx14r just toasted his clutches in his rear. I hear the Torsion wont hold up to hard drag launched but not sure if I have heard of anyone blowin one out. Im in the same situation as you.

 

[EFI]

I would never ever recommend an aluminum housing on a stick shift high powered car.

What about on a stock powered car that does absolutely no hard launches from a dig?

I'm thinking of going with an aluminum diff when I change out the gears in my car since it's mostly a road race application that will remain stock powered. Is there a decent amount of weight savings?

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