[DeTomaso] CLUTCH BASICS / Dick Ruzzin

[Göran Malmberg]

A
This depend on what type of disc that is used. As for comparsion the Sachs 8" organic 
is 460fp and with a sinter disc 622fp using the same pressure plate. 
B
Centrifugal assist is added clampng force, so we have to plot a fp curve over the rpm band.
But the C-assist must be specified by the manufacturer.
C
Thats about the same as for me, I want a clutch that hooks up at low Rpm.
D
Nothing has really changed in princip, but in many racing applications the construction 
design has improved a lot.
E
We have to add the centrifugal clamping force to that of the static, but it will alter over the
rpm band.
F
This is the problem, how could we figur out a good combination without knowing the numbers?
Goran
  A
        Reading a bit more in Tom Monroe's book, there is a table on page 71 with torque capacity vs pressure plate load in pounds, with curves for several disk diameters.  It looks like 2000 pounds is good for over 400 ft pounds.
        B
        But, Monroe also says that the centrifugal assist can more than double the force on the pressure plate in a Borg and Beck or Long pressure plate.  I don't think there is room inside the ZF bell housing for the weights which create the centrifugal assist, so just because someone with a Mustang can handle 500 ft-pounds thanks to the centrifugal assist doesn't mean a similar clutch clutch (minus the weights) can handle the same torque in a Pantera.
        C
        The worst case would seem to be supercharged engines making big torque at low to moderate RPM.  These probably require a twin disk clutch.  Maybe with a diaphragm pressure plate that doesn't rely on the centrifugal assist.
        D
        Surprisingly, it looks like not much has changed, other than the new twin disk clutches.  The pressure plates look the same as what we have now. 
        E
        Regarding clutch torque capacity, one problem is that some pressure plates include a centrifugal effect which increase the force on the disk as RPM increases, so it is not a simple static problem.
        F
        I haven't found the manufactures to be particularly helpful.  They just want you to follow the company line and use the recommended off the shelf setup.  They don't seem to like to get into theory.  From working 24 years in aerospace, about 10% of the engineers did real analysis, and 90% just looked up what had sorta worked before.
        Ken