Another link from this forum.

do some research dude/es. I did. some bloke sent them a diff and something like,, 6 months later he's still waiting!!!(I can't remember the lengthof time, but it was closer to a year).
And as for lasting two seasons.. some bloke used it in his road car. He said it was great...for two weeks, until it became an open diff again.
Personally if someone has a spare diff and some time and they make it them selves..cool. I am just trying to encourage people to do some research as, from what I have read it seems like the product is a waste of money. I would love to be proven wrong as I too would love a cheap LSD.

From my observations of them they do nothing at all. There was just as much wheel spin before as after fitment.
Using a bit of simple physics, look at the leverage ratio between the wheel radius and the effective radius of the gear surface on the housing. Say 300mm/15mm or 20:1.

To get 1.38kg/m (10 ft/lb) of torque at the wheel, you would need a torque of 27.6 kg/m on the side gear. This means a loading of 1840 kg on the gears and housing.

1.38 kg/m is a dead loss anyway as this does virtually nothing on dirt. To get up to the 40 ft/lb breakaway force on the clutch pack required from most LSD's you would need 7360 kg of spring loadings on the gears : ) Now I'd like to see that! Also when a normal clutch pack lsd starts to get speed differential between wheels the spider cross starts to lock up the clutch pack against the housing allowing the diff to drive on the one wheel.
I think the phantom has got a grip on something very personal and its definately not giving traction to the wheels

Not a "true LSD"???

LSD = limited-slip differential, NOT locking-differential. If 1200rc's setup prevents straight-line slip but doesn't lock up around corners, then it is LSD. There are various types of LSD, not just "one" type. Most are spring-loaded. Ford's current LSD is similiar to this in concept.

Be sure to read our last discussion of the Phantom Grip here:


Turn any diff to LSD!

Well done Feral,
Quote:
Love that closing statement

last week I was keen on making one of these THINGS, but after checking out my spare diffs and looking at the options I have to say I agree with feral.
Not only are the rotational diameters an issue but the lack of surface area, therefore frictional grip area is very poor.
They might work but I dont see the design being very effective when driving hard on a continual basis.

I might end up making one with strong compression springs just to see how long the unit lasts but I'm not that confident after checking everything out over the weekend.

It looks like the phantom uses springs similar to those found in motorbike clutches. If your gonna try making one, maybe this could be a source of springs.

I like you analysis Feral----top stuff!

I am opening an invitation for anyone to ride in my rallycar,id love to hear you say it does nothing AFTER that, i've had mine for probably a year and shes still going stong, #### its only $100 or 150 to renew it all after its been done a first time anyway

hey, i just realised if ferals right im prob gonna be driving in the ARC or even WRC one day cause if in my first 3 events i can pilot my 1.2ltr, postive cambered, second hand rally tyred, roll cageless datto quiker than most other barstards out there and i have no advantage with the diff like i thought i had, i just must be a damn good driver

Hay 1200rc, dont take offence to what has been said in the above posts Nobody is saying that you have waisted your money.

I am sure that your diff set up has made some difference to your car, as it should. I was not sure exactly how these things worked until I had a close look into it, and I was dissappointed to see how small the surface area was that did the "slipping". I think the forum got off track a bit once Phantom Grip type mechanisms got compared to multi plate type LSD, which is not a fair comparison.
Thing is, plate type LSD are hard to find and any alternative is worth checking out even if it means replacing the Phantom grip type unit once a season.I am still going to build one once I have done some calcs and worked out exactly which springs I should use, that way I limit the amount of trial and error involved. It will be an interesting exercise to see what effect the unit has in the dirt. I hope mine turns out as well as yours has and reduces the amount of understeer in & oversteer out.

If I have the time I am also going to investigate the possibilities of useing a modified Subaru LSD centre and a better longterm option. I remember someone posting something about this in past forums, any news re this modification.

Paul.