Any opinions on the best differential for 7.5 10 bolt in 1992 camaro? Currently using locker diff from Bravada. It is weakening. Only burns one tire now after burning both.

 

I have the $99 Zexel and it does the job just fine. It will spin em both for the burnout and for the launch AND when it shifts. My car used to shoot out to the passenger side when it would shift but now it just stays straight. It's quiet on the street unless you take a real sharp turn like a U-turn and give it some gas, then you will feel it sensing the torque and beginning to lock. Can't beat it for the price.:hail:

 

Eaton is the best.

 

Eaton...and I've tried them all.

 

go with eaton,it powers my 7.8 1/8 mile at 96 mph

 

They are all pretty good for most street applications. But the Auburn is the least durable of them as it uses cones that wear out over time and make it become much like an open diff. They also have less holding force than clutch style posis. The Eatons use clutches and have better holding power than the cone style ones. They are rebuildable as the clutch setup they use wears out over time. Torsens (Zexels) are an evolution of a locker style setup. They do not use clutches and thus will never wear out (like any diff they can break from being overpowered). They also sense and bias torque to the axles better than a limited slip style differential. The only downside to the Torsen is it requires rotation of the differential to move the worm gears outward to lock the axles together (become "posi") and some drag racers say they have inconsistent results during hard launches. Roadracers, however, swear by the Torsens. Some people say they can hear Torsens differentiating in tight turns but even limited slips will make some noise in tight turns so that issue is a wash really....

So it depends on what you are going to be doing really... But the $99 Zexel is a pretty damn good deal .

I have experience with them all too .

 

Oh yes...Torsens can wear out..and that is their main weakness.

I talked to the Techs at Zexel Torsen for some lenght before purchasing one of the HD units. The model for 3rd and 4th Gen F-Bodies was delayed for two years because of reliability issues related to wear. Mustang models were available two years before F-bodies.

Why...cause the stinking diff in our cars is too danged small. The carrier has to fit inside the ring gear....natch. Thus the smaller the ring gear...the smaller the carrier and thus the smaller the components inside the carrier have to be.

Thre are incredible side loadings placed on the worm gears and the casing in a Torsen. The higher the Bias ratio ...the higher the loadings. The stock GM unit has a Bias ratio of only 1.5 to 1....good enough for the street and makes it relaiable....but not high enough for racing. Proper Torsens for racing or off road use usually have a Bias ratio of between 3 to 1 all the way up to 6 to 1.

It took some time before Zexel could develope a Diff ( for our cars ) that could be released to the public and have reasonable reliabilty. Still, the bias ratio was limited to around 2.5 to 1 as memory serves me.

What will eventually happen with a 3rd or 4th gen car is that the worm gears shafts will eventually elongate the carrier housing. Then you get too much backlash between the worm and spur gears and rapid destuction is the result.

Events such as Autocross and Road Racing....which is the Torsens forte....are also it's weakest point. High HP, gumball tires and Torsens = rapid wera. Unfortunate but true.

I got 2 and a half seasons out of my Torsen on my ESP Camaro before it started to fail. That was considered by Torsen as pretty good. They've seen them fail in as little as one season on our cars in Autocross. A HMS team mate ran a Zexel Torsen in a different ESP car and he got something like 6 months out of it.

Now before this sound like all doom and gloom...remember a few things. My use was in extreme situations. Also I was using the Higher Bias Racing version...which is not as reliable as the $99 OEM take off Specials on the market. ( Curious thought: Why are SLP taking out all of those new Torsens and selling them dirt cheap.)

Torsens are a great diff....once the R&P gets over about 8.5" in diameter ( in a vehicle of our weight and capacity. Miata's and other girly cars can of course use a smaller unit no problem. ) They are incredible in the wet...absolutely night and day over an Auburn or an Eaton. Sadly they still have relaibilty issues....because of the poor design of our diffs. Now if you've swapped in a 12 bolt or Ford 9" conversion then....WaaaaHooooo!!! Go with the Torsen.

BTW...if you get a Torsen ...always, always use Synthetic gear oil. Torsens generate a lot of heat and loadings on the gears. Mineral oil is not sufficient. I always used Amsoil..and that probably contributed to my Torsens longer than average lifetime.

 

BTW...here's a disgusting comparison as to how under-engineered our diffs are. I used to road race Datsun 510's, 240's and 1200's back in the 70's . An R200 diff...common on Z cars is 7.8" in diameter. Would fit in a 510 as well. 240's were typically 2,500lbs or less and 510's were around 1950 to 2,000lbs.

My C Sedan Datsun 1200 weighed 1405lbs wet. It had 142 hp @ 8,500 RPM ( Redline 9,200 ). Torque was non-existant.

In later years I changed up to a 510 wagon diff as the 1200 diff was a bit weak. The 510 Wagon diff had an 8" Freakin Ring and Pinion !!!

No wonder we break the friggin' diffs all the time in our cars!!!!!

 

Interesting... I never really heard that they have problems with the worm gears elongating those bores but it stands to reason that they would with the forces applied to them. Am I understanding you right in that you are saying the standard Torsen is better than the HD one with this concern?

I believe you are correct with the 2.5:1 ratio of the HD T-2R diff...

I was not aware that Torsen made a diff for the Ford 9".... But if they do, I know what my eventual setup will have .

Thanks for the first hand info .

 

Yes..the standard OEM is better than the HD version in respect to reliability...for our cars. The higher Bias Ratio of the HD unit produces proportionally higher gear and case loadings.

The HD T-2 has the 2.5 to 1 Bias Ratio. The newer HD T-2R has a higher Bias ratio and has clutch packs to preload the unit.

During my talks with Zexel after my Torsen had worn out ( Fall 2000 ) They offerred me a Pre-production T-2R at their cost to evaluate. I almost went with this option...but they were still hedging on the longevity. As budget was a consideration, I eventually went with the Eaton and have been very happy with it. Had to change the setup of the car though. Rear end became much more " Taily " with the Eaton.

Several Mfg's make Torsens for the Ford 9". Zexel, Gold-Trac, Tru-Trac etc all make units. Have a look at the Production schedule for various models. Note that Zexel stated making Torsens for the Ford 9" back in 1995...now look at how much longer it took to develope the 3rd\4th Gen Torsen. Purely a engineering problem due to the small size of our diffs.

http://www.torsen.com/oem.htm

Note that the HD-T2R is till not " officially " listed as for sale to the general public for our cars. . You can order a T-2R for our cars...but only by special order. Mustang 8.8" diff readily available in a T-2R...bigger case...larger and sturdier components....Sigh


Edit: Spelling

 

I never noticed that Torsen made a diff for the 9".... But I have seen the other manufacturers names mentioned but was not aware that they used the same worm gear design.

I recently rebuilt my 10 bolt with a T-2R. I got it off my bro-in-law who bought it through Global West earlier this year so I am guessing that it is the newer one. I know the thing was insanely heavy for being the size it is! He said something about it not being the same as the HD T-2 that SLP and the like sell for our cars and that he had to special order it from Global West and it cost him more than the $500 going price of the SLP one.... I was like "yeah right... ya want more money out of me huh?" But it sounds like it may actually be worth more.... I think I got a good price on it .

So far it has worked great. Absolutely zero complaints in any area. But it will be a while before I get the thing on the road again as the 383 just went in, the big brake kit prototype is nearing completion, and snow is falling as I type this .

It's good to hear that you have had good results with the Eaton in a road racing application too. I have only heard feedback from drag racers and street racers previously, but they all seemed to have good things to say as well. It is nice to know that something that is as readily available and cheap as the Eaton will get the job done. I certainly wouldn't want to pay full price for a Torsen T-2R! And definately not over and over!

 

Sounds like you got a T-2R then. I know Zexel was working on the durability problem. They sure are nice when they are working...especially in the wet. So much more controllable.

I think this will work as a quick way to tell if you have a T-2R for sure. Jack up the rear. Rotate a rear tire by hand. A standard or HD T-2 will rotate the other wheel in the opposite direction...just like an open diff.

A T-2R has clutch plates to pre-load the side gears...so rotating one wheel should cause the other wheel to rotate in the same direction. At least that's my take on things.

My T-2 definately had opposite rotating wheels when jacked in the air.

 

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The OEM units work fine in stock applications. Just High HP, Competition events such as Autocross and Road Racing is where they wear out. For street use with a stock 305 they are fine.

Make sure that you use a Premium Brand Synthetic Differential lube. Amsoil is one of the best.

 

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your car doesnt have a posi, but I would suggest one just for the safety it gives you with the added traction. Go for it.

 

Eaton....ive had it for 2 years. its indestructible. great for street.

 

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Jack the car up...put it in neutral and spin a rear wheel. If the other rear wheel spins in the same direction then you have a posi. If the other rear wheel spins in the opposite direction you have a non-posi diff. ( Note: this test does not apply to Torsens ).

Alternately just hammer the thing in 1st. Two Black patches =Posi. One Black patch = Standard diff....or a Dead Posi.

Note: The Torsens are made only for Ten Bolt "Saginaw" Diffs. If you have a Nine bolt "Borg Warner " diff you cannot get a Torsen.....to the best of my knowledge.

 

that doesn't always work either, i have a picture of TWO big black tracks from when i still had an open diff.

 

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i beleive all 88 and up had 28 spline axels, which is required for SLP's $99 unit, so your 89 should be fine, just replace the bearings and axle seals while your in there, and i personally would do some gears

 

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