Limited Slip Differential

[Trevor Jessie]

I wanted to start looking for a limited slip differential. I asked on the Classic Motor Sports forum (thinking I knew what I wanted), but I decided to come back here and see if anyone had any experience. I'm looking for something to use for spirited street driving so that I have less wheelspin on hard starts and coming out of hard corners. Plus, I could use a little help on wet roads.
Any suggestions or ideas or links to relevant info?

 

[jollyroger]

You only have a choice or two. Both are not cheap. Quaife(I think that is spelled right) makes a unit. I think there is one more brand from Mini Mania. Both cost a number of bucks.
I like a welded diff on the track.

 

[JamesWilson]

Quaife in the UK has a site, it links to their US vendor, Quaife America.

MG Prices (£UK), MG Prices ($US)

Correct me if I'm wrong, but it seems the US price is 2 1/2 the UK price... seems a candidate for self-importation....

Edited to add:

At current exchange rates of £1 ~ $1.80 the 2.5 over-compensates by about £350, less transport and taxes....

 

[Trevor Jessie]

I was considering a Quaife, but then someone mentioned a Tran-X.
$1200 is not too high, but then I could also try to find a LSD rx7 axle and shorten it.

 

[Matthew E. Herd]

Crap, they sure aren't getting any cheaper. They used to be $1350! Does anyone have the link to the minimania unit?

 

[RobSelina]

[ QUOTE ]
but then I could also try to find a LSD rx7 axle and shorten it.

[/ QUOTE ]

I think shortening a stouter axle makes a lot more sense if it's not a race car. We've all seen too many posts about broken axles under hard driving. For the cost of the LSD you could get a whole rebuilt rearend spec'd just the way you want it....

 

[PeterC]

There's also this. Some are skeptical becasue of the price. It works. Bill Perry of Rivergate uses, and probably sells them
https://www.phantomgrip.com/product_lists.php?make=Austin%20Healey

 

[RobSelina]

[ QUOTE ]
There's also this. Some are skeptical becasue of the price. It works. Bill Perry of Rivergate uses, and probably sells them
https://www.phantomgrip.com/product_lists.php?make=Austin%20Healey

[/ QUOTE ]

Looks like a variant of the lock-right/quick-lock/aussie locker based on the installation instructions.

I'm not sure I like the use of the stock spider gears, especially the grinding of the surface. I dont know enough about how they're hardened but I think it's only a surface treatment, much like axle shafts.... I'm also not entirely sure how it locks into place. The LSD 'box' is firmly held to the carrier by the center pin, but there doesn't seem to be any positive locking mechanism to the spider gears, so the way I'm looking at it, if you stomp on the gas hard enough, you could still spin the box against the spider gear...I must be missing something.....(they claim its a locker under acceleration. As force is exerted on the center pin it will push the plates harder into the spiders, but I don't see anly locking action)

While it doesn't offer any strength improvements like a full-carrier LSD does, it's price is certainly right!

 

[Matthew E. Herd]

The opinions on GRM forums were pretty negative, and I didn't like the design. While I have a Scout and investigated lockers, I can't say how they all work, but I know that the ones I looked at didn't work the way the phantom grip goes. Its design is awful, as it puts large loads on the spider gears which the carrier is not designed to withstand. I do know that about it, though I have decided not to try it. Some things are just asking for trouble.

 

[aeronca65t]

The other bolt-in choices are Tran-X (made in the UK). Spridgetech sells them for about $1100. This may be the one Mini-Mania and Acmespeedshop sells as well.

https://www.tran-x.com/DiffsHTML/sprite.html

Also, Jack Knight LSD diffs sold through Peter May Engineering in the UK and popular in the Euro-Spridget Series. Go here (and browse through the "Specialist Products" area to find this....lots of other neat stuff too!):

https://www.petermayengineering.co.uk/

For the record, I am racing with a open 3.9 diff in my 1500 car. It's only a problem in a few 2nd gear turns at Pocono. If I did a lot of slower 2nd gear stuff, I'd use a welded diff. I've driven a welded diff at faster tracks (Summit Point and Bridgehampton) and I actually think the the open diff handles better for faster stuff.

The other 1275 Spridget I race occasionally has a Quaife. It snapped an axle at Watkins Glen last year and wouldn't move, just like an open diff (I always though an LSD would drive the car on one axle, just like a welded diff).