Just a little something for my fellow physics geeks who are into this stuff.
We've suspected for a while now that something was a bit hinky with the clutchpack diffs, and also that the locked diffs can work out faster.
I always thought it was funny that there was no pre-load adjustment on the diffs, and my suspicion was that preload wasnt modelled, as generally if there is an adjustable parameter modelled, we can adjust it.
I did the following test and it seems like there is indeed no preload on the clutchpack diffs at all, which means that as you pass through the neutral torque zone between power and coast, there is no locking and the diff is effectively open. Its possible that this contributes to some of the difficulties people have with car behaviour on corner entry because as you come of the brakes and start to turn in, you have an open diff for a moment.
Anyway, the experiment went like this for those that are interested.
Run up to full speed at the oval, then put the car into neutral and drive a turn just coasting. This should meant that the diff is under a no-torque condition and so the only torque transfer should be as a result of the preload in a clutchpack diff.
With an open diff, this experiment saw a very small difference in longitundinal force between the rear wheels, probably just as a result of the outer loaded wheel having more rolling resistance (60N difference fact fans).
With a locked diff, as you would expect there was a big torque transfer.
But with a clutchpack diff with full coast and power locking, only the exact same tiny difference of 60N was observed, which effectively means that when not subjected to torque the clutchpack diffs act as open diff.
Ergo, preload is not modelled.
I think.
We've suspected for a while now that something was a bit hinky with the clutchpack diffs, and also that the locked diffs can work out faster.
I always thought it was funny that there was no pre-load adjustment on the diffs, and my suspicion was that preload wasnt modelled, as generally if there is an adjustable parameter modelled, we can adjust it.
I did the following test and it seems like there is indeed no preload on the clutchpack diffs at all, which means that as you pass through the neutral torque zone between power and coast, there is no locking and the diff is effectively open. Its possible that this contributes to some of the difficulties people have with car behaviour on corner entry because as you come of the brakes and start to turn in, you have an open diff for a moment.
Anyway, the experiment went like this for those that are interested.
Run up to full speed at the oval, then put the car into neutral and drive a turn just coasting. This should meant that the diff is under a no-torque condition and so the only torque transfer should be as a result of the preload in a clutchpack diff.
With an open diff, this experiment saw a very small difference in longitundinal force between the rear wheels, probably just as a result of the outer loaded wheel having more rolling resistance (60N difference fact fans).
With a locked diff, as you would expect there was a big torque transfer.
But with a clutchpack diff with full coast and power locking, only the exact same tiny difference of 60N was observed, which effectively means that when not subjected to torque the clutchpack diffs act as open diff.
Ergo, preload is not modelled.
I think.