LSD breakaway torques Options

[pcar916]

I have enough mileage on the 40/60 LSD to measure the breakaway torque. Now that the Paul Guard is no longer at GT and having talked to Matt for internal rebuild specs, I have a question for those of you who track that specification.

Excellent customer support by Paul before him, and now Matt, on my diff by the way, but Matt has no way of knowing what Paul dialed into my diff when it was assembled, and I can't find where I wrote it down. He questioned me at length about my driving style and how the car was to be used before building the unit. Now, before anyone brings it up I know there are more things involved than simply overcoming the pre-load created by the Belleville washers, like having more or fewer actual clutch plates, so feel free to include those assumptions in your descriptions if needed...

what breakaway torques (accel/decel) do you clutch-types build into your diff's in our mid-engined machines?

For those who never heard of this the "breakaway torque" is the amount of torque you have to apply to one rear wheel (off the ground) to make it rotate when the other wheel is locked in place and can't turn. The differential has a different number for acceleration than deceleration unless it's setup to the same angle for both directions.

[Richard Casto]

Ron,

I am not helping to answer your original question. I would also love to hear some good empirical information, but I suspect that the vast bulk of those who may have an LSD has no idea what their break away torque value is. For those of you who do actually know, please share! (IMG:style_emoticons/default/smile.gif)

Anyhow, I typed up this article earlier this year and figured you or others might find it interesting...

http://www.blueskymotorsports.com/index.ph...20&Itemid=6

One thing to remember when talking about clutch type LSD is to not confused "ramp angles" and "percent locking/locking factor/anti slip effectiveness". It seems that people tend to mix them up and it generates a lot of confusion. For example a 30 degree ramp angle could result in 40% or 80% locking depending upon clutch pack configuration.

Richard