Suggestions on Differential internals

[RET_COP]

I'm looking for the best of both worlds for differential internals. I plan on some auto-cross so I want to keep to a limited slip type so its open on turning with light load but when I plan on hammering it with sticky tires I want good lock up with durability. I have an 8.8 with a Trac Lok ( clutches) with a 28 spline. The reason for changing is I want to go to 31 spline axles and if I'm going to do this I will make a change to the limited slip if necessary. I like the gear type limited slip (Tru-Trac) with no clutches.
So... guys fire away and enlighten me so I can make a decision (make and type).
Thanks again, and everyone here at Club Cobra a Happy Thanksgiving
Lou

[Jerry Clayton]

for what you say the Eaton Detroit True Trac will be the best---the ford 8.8 tru trac had some clunking on coast down that they were looking for a cure for---

While you at at the change over---you should consider having the housing ends changed and get rid of the c-clip axles

[MikeCo]

You may want to consider the Gleason torque sensing differential. Good unit and not nearly as pricey as the Quaiffe.

I had great luck with it in a '98 Mustang Cobra I used to own for autocrossing and drag racing.

[mdross1]

Whatever your choice hopefully the learning curve will not be too expensive.My 9" with TrueTrac surprized me a couple of times but was able to save it before any body damage.Good Luck

[vector1]

i have a torsen setup in one irs and like it. have another with trac-loc, this setup requires the right amount of slippage, not enough and it annoyingly chatters through turns and would probably push at the track, too much slippage and it is useless--adjust with limited slip additive.

[ACademic]

Would love to hear Greg Schroeder's take on this. I recall he installed 31 spline axles and the Tru-Trac in an 8.8 IRS for his Superformance. Was bullet proof at the drags but not sure how it behaved for him on the street and when driving aggressively around corners.

[RET_COP]

I use Royal Purple Max gear 75/90 and the rear seems real smooth. (it has low miles with no abuse at this time) Maybe I'll just leave it alone for now. Just changing to a 31 spline axle isn't a 1 hour swap because of the different size bearing(s) used for 28 spline. Is there a stronger 28 spline (different metal)? than stock. I have a B&B car with no documentation for the rear. Bryan said he thinks its more likely 28s but I'll have to pull things apart to be sure. Its not broke but Ill be getting stickier tires for Christmas.
I found a thread at B&B with discussion between Rick Lake and Wbulk (wayne) which was very informative.
CRIPE if the wife would just give me $5,000 for Christmas and I'd upgrade everything
Thanks for the replies
Lou

[Three Peaks]

Dutchman axles will make you a stronger set of axles for whatever hp you are planning to run.

www.dutchmanaxles.com

Bob

[Ant]

Lou,

I am running in my 8.8 Eaton posi with carbon fibre clutches, I havent tried this system yet but have read good reports. Have used Detroit locker etc in a few race cars they can be a bit brutal on the road if the car is setup for track!

Thought about going 31 spline as I can be hard on drivetrain with my road racing, decided to leave it as my car is lightweight and not doing any real drag racing. I am using 28spline chromemoly Porsche 930 style CV joints and 4340 axles and feel for general handling etc a good LSD is the way to go, having just fitted the Eaton posi I dont see a problem in taking the back cover off and replacing the clutch pack.

[Tom Kirkham]

Here is a comparison of a couple of diffs...

http://grassrootsmotorsports.com/articles/whats-diff/

[mdross1]

Mine powered with big block and clutches set a tad tight was fun getting used to.A little too much throttle in a turn and it was fight to get things back under control.A 9" set up right is bullet proof.At first considered an IRS but was afraid what big horspower and big gum shoes would do to it.Good Luck

[LMH]

Hey Lou
Are we talking IRS or live axle?
I have a 31 spline 8.8" IRS diff and the problem (read $$$) was the inner CV joints. I'd probably look for something stronger in 28 spline if that's what you have now.
Larry

[Ant]

Originally Posted by LMH

Hey Lou
Are we talking IRS or live axle?
I have a 31 spline 8.8" IRS diff and the problem (read $$$) was the inner CV joints. I'd probably look for something stronger in 28 spline if that's what you have now.
Larry

Is the problem the OEM tripod plunge type CV or the 28 spline axle?

[Three Peaks]

The Ford 31 spline stub axles are almost impossible to find for a reasonable price. The rest of the CV's are pretty much the same parts, except the Cobra units with the 31 spline stubs have a larger axle shaft.
The weak point seems to be the CV axles, which Dutchman or other axle shop can make out of a stronger material to order.

Bob

[RET_COP]

Larry, it's a straight axle.
Very informative guys, thanks for all the reply's and suggestions.
Lou

[blykins]

Originally Posted by Jerry Clayton

for what you say the Eaton Detroit True Trac will be the best---the ford 8.8 tru trac had some clunking on coast down that they were looking for a cure for---

While you at at the change over---you should consider having the housing ends changed and get rid of the c-clip axles

I would agree with this....True Trac would be a good diff for autocrossing, street use, and even some road race applications.

[LMH]

Like Bob says, the expensive part on a 31 spline IRS diff is the stub axle. It took over a year to find mine as I didn't want to pay for them from the dealer. The Driveshaft Shop did my axle shafts.
On an 8.8" IRS unit, one of the other weak links is the rear cover and it's mount. I've seen the cover broken a couple times. I have an after-market cover that's much beefier.
Larry

[ACademic]

Larry, you might want to check this out as well.
http://www.steeda.com/store/steeda-d...ang-cobra.html