[Spridgets] Diffs again, if I may

[Deikis, John G]

Daniel:



Torsen? Gleason? Quaife?  Are you trying to pick a fight?!  ;-)

Be that as it may, why would Bill say that if I lift the inside rear
wheel in a turn, the Phantom Grip will no longer provide any benefit?



JohnD





________________________________

From: Daniel1312 at aol.com [mailto:Daniel1312 at aol.com]
Sent: Wednesday, June 27, 2007 2:40 PM
To: Deikis, John G; spridgets at autox.team.net
Subject: Re: [Spridgets] Diffs again, if I may



What Bill says is borne out by my own experience.  The Phantom Grip
device works like a Torsen diff NOT a clutch plate diff.

What this means is that when one wheel trys to rotate faster than the
other the Phantom Grip resists it and trys to keep both wheels turning
at the same speed.  The effect in any situation is that the rear of the
car will seek to step out towards the right (don't know why it's always
to the right).  In this respect the Phantom Grip action is just like the
Quaife Automatic Torque Biasing diff which they are not allowed to call
a Torsen because if they do Gleason will sue them.

I personally consider it's unhelpful to think of the Phantom Grip as
having clutch devices as this can lead to confusion with the action of a
clutch plate limited slip diff which is quite a different thing
altogether.


A clutch plate limited slip diff like a ZF seeks to switch power from
the wheel that has less grip to the wheel that has more which invariably
overloads that wheel and thus reverses the power back again and so as
this cycle repeats the rear of the car fishtails as the wheels fight for
grip.


In a message dated 27/06/07 18:06:05 GMT Daylight Time,
John.Deikis at va.gov writes:




I have a Phantom Grip on my vintage race car.  Bill Perry told me it was
essentially a "torque sensing device" and would limit inside wheel slip
until the inside wheel lost all traction.  He said at that point there
was "zero torque" so the Phantom Grip did nothing.

I'm trying to understand this.

Can someone explain in simple terms how the Phantom Grip spring-operated
clutches work in different low traction situations?