Limited-Slip Differentials

[RSTPerformance]

looking for your opinions about the Phantom Grip LSD (www.phantomgrip.com) vs. the Quaife (www.quaifeamerica.com).

I figure most people will probably say that the Quaife is better, but please include more info, look at the price difference:

For the Audi's a Quaife suggested retail is $1,295.00 (but you can get one for as low as $1,150.00) and the webpage for the Phantom Grip LSD is $349.95 + upgrades springs at $29.95 = $378.90.

What are your thoughts? Justification of higher cost?

Thanks for your input.

Raymond Blethen
RST Performance Racing
www.rstperformance.com

PS: We can add in a twist to the convo and go with the other option... Welded diff.

[ITS_Racer1]

Timely topic for me. Over the winter I invested big $$ on the Quaife after running a welded diff on an ITS240Z for a number of years.
First time out with the Quaife at Sears Point this weekend, I was leaving 50ft strips of rubber out of T2, T7 and T11. I was also getting significant inside drive wheel spin through the high speed corners.
In all fairness, the support person at Quaife has been responsive and offered some suggestions on suspension changes that might help. Problem is I will need to soften things and measure their effect.
I thought this would be a bolt in and go deal, and it has not been so far.
At this point, keeping the welded diff (and my money) is the attractive option.

[bill f]

RSTPERFORMANCE

Ray,
Before you invest (lose) your money, contact joeg, who writes frequently on the Ford side for his experiences.

My understanding is, it essentially creates a "bind" between the pinion and side gears to tighten up the unit and make it more difficult for the gear rotation to occur. My take on this, is that it will create additional friction (wear) of the gear faces, and friction surface of the side gear inside the carrier. To me, this spells "additional material floating in the gear oil", which rhymes with...

I'd fear that the floating material would be eventually between the ring and pinion, which is not a good place to be.

Joe has emperical information.

Good racing.

Bill

[joeg]

Ray--IMO, save up your money and get the Quaife.

We have visted the Phantom Grip topic many times and many times people have said they thought the product's name was neat.

Cheers.

[m glassburner]

We have the phantom...starting our fourth year... change fluid every weekend... have not had a problem.

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[BMW RACER]

Hey there ITS Racer. I tried the Quaife in my old 2002 and didn't like it for the same reason. It seems to work fine as long as the inside wheel is on the ground, but as soon as that wheel got airborne it would spin. Now if you stiffen the front and soften the rear the diff would work better, but I'm not convinced that is ultimately a faster set up. I have heard a lot more positive feedback on FWD cars. Of course we all know they are driven by the wrong wheels anyway ;-)

[racer-025]

thats the problem with the quaife. once one wheel gets airbourne, it unlocks and has to get the wheel back down and settled before it locks up again. I think the opm unit with the block lsd and clutch system probably works the best. The PG unit is not bad, but wears. I'm using the PG unit.

edit: I am talking FWD here...

[This message has been edited by racer-025 (edited April 07, 2004).]

[Greg Amy]

The new Grassroots Motorsports that arrived on my doorstep today compares and contrasts all of the various differentials.

You do get GRM, right?

[jc836]

Great article and could easily become a FAQ.

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Grandpa's toys-modded suspensions and a few other tweaks
'89 CRX Si-SCCA ITA #99
'99 Prelude=a sweet song
'03 Dodge Dakota Club Cab V8-Patriot Blue gonna tow

[Danny M]

With a quaife or any other GEAR driven LSD, it essentially works as a torque multipler. For example, it can give the left rear 5 times more torque than the right rear is getting. The problem with this is that if one tire is airborn, putting zero torque to the ground, the other tire will do the same. Viscous units (such as what came from the factory in my car) will drive one tire no matter what the other tire is doing. The downside is that the viscous fluid can overheat and reduce the efficiency of the LSD. Clutch type LSDs work simlar to the viscous unit but rather than having overheating problems, they wear out and need to be rebuilt in time.