Kai:
I have done a little studying on them, and I have concluded
they are the worst sort of ghetto hack. Mind you, I have not actually
tried one, so you would have no trouble making me look like an idiot
by trying it and reporting positive results. After shooting my mouth
off for years, I have learned to eat lots of crow. =:-o
There are several different ways to build an LSD, all of them
with different tradeoffs of cost, reliability, effectiveness, etc.
The Phantom Grip is of the "Clutch" variety, where a pre-loaded clutch
is used to lock the two axles together. When enough torque difference
between the two axles occurs, the clutch slips allowing the wheels to
rotate at different speeds.
The problem I see with the PG is that there is no clutch, in
effect. The device relies on the friction between a spring loaded
steel block, and the edge of your axle gears. The shape of the
gear edge is not well controlled (after all, it is not the
actual gear teeth, but merely an adjacent face never intended to be
load bearing). In some applications, the PG uses only a rough machined
gear face as the clutch. Tell me how that is going to work!
I would expect the actual results to vary wildly, depending
on the shape and surface area of the gear face. In addition,
because the gear face was never intended to be used as a clutch
surface, wear would be unpredictable, depending on which part of
the gear was hardened, and how deep that hardening goes.
In a regular clutch LSD, there is a stack of clutches to
distribute the load and wear over a large area. These designs
require special friction oil additives to make the slippage
predictable. The PG has none of this. What do they know
that everyone else doesn't? Quaife sells an LSD for $1,000. Is
Quaife stupid? Why can't Quaife create a PG? They do LSDs for a
living...
In addition, I have had a dickens of time finding any
testimonials in chat rooms, etc. Everyone seems to know "a friend
of a friend" who had great results, but the one or two cases
where the testimonial is in the first person, all they do is
gripe about how it doesn't work, or it worked for a few weeks
and then quit.
So I remain unconvinced that this is anything but another
"Split Fire" spark plug, that offers better gas mileage, lower
emissions, and higher horsepower, yet no one is able to
substantiate their claims. In other words, it's all marketing
hype and unprovable claims.
Someone should probably try one just for the heck of it,
but it won't be me. Kai, the question you have to ask yourself
is "Do I feel lucky?". Well....?
Waiting to be revealed as the village idiot,
Vance
------------------------------
1974 Mimosa Yellow Triumph TR6
Cogito Ergo Zoom
(I think, therefore I go fast)
-----Original Message-----
From: Kai M. Radicke [mailto:kai@radiohead.net]
Sent: Thursday, September 12, 2002 8:48 AM
To: 6-Pack
Subject: Phantom Grip LSD - the catch?
Undoubtedly anyone seriously active or interested in British sports car
racing has seen these Phantom Grip LSD units being advertised lately with
greater and greater penetration into magazines and also now known suppliers
of quality racing components are beginning to stock them. For those that
haven't seen them yet:
http://www.phantomgrip.com/
A Phantom Grip LSD conversion for your TR6 is listed at $349 from the
manufacturer, and I've seen them as low as $296 from distributors. So if no
one has used one yet, who is going to be the bold guinea pig who tries one
first? (or have I just volunteered myself)
Kai
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