Limited slip for a 915...price?

[Walko9]

i was told that the Modena diffs are the same as Guard ??
Ie one co is making for the other

Michael

[Joe901]

I think Modena used to supply Guard some time ago but I am not sure if this is now the case.

Modena was the manufacturer and we have used many of their LSDs in Historic Ford Escort Rally Cars and they are very well made and have excellent quality plates.

[ttweed]

I am a little confused how a torque biasing diff is described as either 40/60 or 40%.

Joe-
If you are talking about the description on the Guard site, they never call a TBD an LSD in order to make a firm distinction between the two types. While both diffs may "limit slip" in a general way and thus belong to the same "family" of devices, Paul Guard always reserved the term "LSD" for the plate-type diff and "TBD" for the gear-driven type in discussing them to differentiate between the qualities of each. Thus when you read "(a) Street / autocross - Torque-biasing suitable for most applications, especially autocross. 40/60 (or 40%) LSD for all Turbo and high-performance street cars," he is recommending either a TBD or a 40/60 ramped plate-type LSD. The 40/60 term does not apply to the TBD. Note the period between the two sentences. They are two separate recommendations--he is not describing the TBD as being "40/60."

This semantic preference is explained further down in that article when he says, "A great deal of confusion is caused by optimistic sales information distributed by companies that only offer torque-biasing differentials, or when a TBD is described by a vendor as a “limited-slip differential”.

HTH,
TT

[davewadd]

I think the info provided became a bit overwhelming for my novice brain...but I'm back on this topic again. The wheel spin coming out of corners at last weekends autox was killing me. I'd have to be 2 seconds faster if I had the traction of the other cars in my class.
Can someone suggest a So-Cal expert on this, who can do the installation? I'm leading towards the torsion-type based on cost and use.
thanks
Dave

[Jens]

Great information in this thread. What's involved in setting up a TBD in a 915 gearbox? Is it a Saturday afternoon project? Thanks.

[davewadd]

I think it's an afternoon project, but I've also been told that I may need a ring & pinion at the same time.

[edmayo]

Once you change the differential unit you have just lost the all the factory set-up. Installing any new/different carrier/differential unit will involve re-establishing the pinion/ring gear backlash and differential bearing preload. Not doing this could lead to premature pinion/ring gear wear. I'm sure there are many who just bolt stuff in and go,,,some are lucky,,,some are not.