924Board.org

simsport · Joined: 06 Nov 2002 Posts: 573 Location: UK Warrington

I bought a Phantom Grip unit for the sprint car. It is for the 944S2 box I have fitted in place of the snailshell.
It fitted very well after a mild tweak and (unlike some stuff I have bought and have complained about) seems to do just what they said it would.

Its an odd looking device. Not a true LSD but a locking block assembly which rotates to deliver cornering grip and locks in a straight line.

At a recent test day the car pulled better than ever before out of the corners and exit speeds were well up.

I cant say if it will keep working well yet, neither can I say if it will wear the diff at all. However it does seems to work....cool!

Cheers
Simon
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Blown is always best!

Raceboy · Joined: 01 Mar 2004 Posts: 2326 Location: Estonia, Europe

How much did it cost and was it difficult to mount?
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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold

'84 924, turbocharged, sold.
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81turbo · Joined: 03 Nov 2002 Posts: 1065 Location: Oakland, CA

Well it looks like your spider gears will be toast soon.

http://www.924board.org/viewtopic.php?t=5706&highlight=phantom+grip

simsport · Joined: 06 Nov 2002 Posts: 573 Location: UK Warrington

Remains to be seen.
The Phantom Grip unit has been used on numerous front wheel drive cars over a number of years. Several magazine tests saw increased performance and I did not see any reference to damaged spider gears.

There are always tales of this failure or that...however rarely does anyone have direct evidence unless they try it themselves.
So I am, and will tell you all if it buggers up the diff.

I should point out though that the blocks in the unit are self lubricating. As long as the diff is well lubed itself I cant see a direct cause for spider gear wear. The gears do lock themselves in a standard diff, just one side only. I asked a UK gearbox specialist about the unit and his exact words were "what a good idea, cant think why nobody else here has done this"..

So, like I say may be good, may be bad...but worth a try.
Will keep you posted.

Cheers
Simon
PS It costs about 350 dollars and fits very easliy.
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Blown is always best!

Lizard · Posted: Sat Mar 26, 2005 11:31 am Post subject:

the main reason for spider gears becoming toast is that when they install the diff they do not shim it properly
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3 928s,

J1NX3D · Joined: 06 Feb 2003 Posts: 1333 Location: New Zealand

well the best place to test stuff is in competition! thanks Simsport for taking the hit for the team!!

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'86 944

simsport · Joined: 06 Nov 2002 Posts: 573 Location: UK Warrington

Eeek....Gulp.....OK!
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Blown is always best!

Lizard · Posted: Sun Mar 27, 2005 3:20 am Post subject: Re: Gulp!

simsport · Joined: 06 Nov 2002 Posts: 573 Location: UK Warrington

Er...no.
The Phantom grip is not like other diffs in that it does not require the diff to be shimmed.
Shims in the diff are for the relationship between the gears within and not the Phantom Grip which has a specified clearance before the retaining (grenade!) pins are removed.
So you see no shimming of the diff is required. Although it might be that you will want to shim the springs in the Phantom Grip unit to get best performance.

I did much as you said. Roughly measured the clearance before the grenade pins were removed and realised that there was enough but not too much such that the spring pressure of the unit would not fail to deliver the locking effect.

I did spend some time grinding the gear faces to a smooth finish to prevent unever wear (friction?) and get best performance.

Look, I know everyone is cynical about these units. I am a little myself, but rather than suggesting I'm a fool for buying it, or fitting it my way lets see if it works. It may and it may not, time will tell and if you and everyone else is correct I'll owe you a pint (not all of you!).

Cheers
Simon
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Blown is always best!

numbbers · Posted: Tue Mar 29, 2005 10:04 am Post subject:

I am with Sim on this one. He is brave enough to try it, and we will all learn from his experience. Thank you very much, Sim.
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1980 924 Turbo

Lizard · Posted: Tue Mar 29, 2005 12:42 pm Post subject:

I do applaud you for trying it, but I thought that the damage it caused wasnt from not shimming the gears, but shimming the ring gear so that it got proper contact with the pinion gear as if there is too much play there it will eat itself apart. or am I mistaken on this.
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3 928s,

simsport · Joined: 06 Nov 2002 Posts: 573 Location: UK Warrington

Ah, I see what you mean.
Well, you are of course spot on for in a normal aftermarket LSD fitting the ring gear and pinion relationship may change and shimming may then be needed.
Sorry I misunderstood you.
The Phantom Grip however does not change this as it sits inside the original diff casing and the crown wheel and pinion remain as before.

Cheers
Simon
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Blown is always best!

Lizard · Posted: Wed Mar 30, 2005 12:32 pm Post subject: Re: Diffs

turbobob9242 · Joined: 08 Feb 2003 Posts: 138 Location: Hinckely Ohio

Simsport,

Is the phantom grip unit sill working? I have been thinking about getting on too but am not sure if it holds up!
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Bob Ward
80 9214 turbo, w 5.3 LS V8

simsport · Joined: 06 Nov 2002 Posts: 573 Location: UK Warrington

It does seems to be working well. If you check the performance upgrades section you can see a photo of the car drifting and leaving two lines of rubber.
The car has won in 3 out of 4 events I have driven it in, and the fourth was when my brother-in-law drove it!

Cheers
Simon
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Blown is always best!