Well the guy at Quaife is an idiot. He didn't even realize that the QDF-5W that's still listed at their site is out of production now. He made me jump through a bunch of hoops just to find that out what he could have told me himself, so that company can go get screwed as far as I'm concerned, now and for the future.

So who else is making a unit that I can order for my 05 XKR?

 

There is one listed here - with worldwide postage included.

Jaguar XK8 XKR XJ8 XJR Quaife ATB Limited Slip Differential | eBay

Don't know if that price is any good!?

 

That's a good price. I bought my a year ago from a place here in the US but that had to order it from the UK. It took about 3 months to get it. I paid $1545 for bit; Quaife wanted $2100 direct from them. They still have it listed and it's down a $100 from when I bought it. Here's the link:

Part Number QDF5W

I've been very happy with it.

Mark

 

What is the advantage? And what fitting is required? curious.

 

More power to the road; you simply cannot spin your tires. I know, I've tried. The ATB stands for automatic torque biasing; torque is shifted from the wheel that is about to slip to the other drive wheel. Cars like our XK8/Rs should have come with an LSD but Jaguar upper management didn't want to steal customers from big brother Aston Martin.

As far as fitting, forum member motorcarman, who runs a small independent jag shop near my home, installed it for me. I understand it was very straight forward but you do have to pull the differential.

Mark

 

You can choose between different setups, so the Quaife (ATB one) or clutch type systems. Personally I prefer clutch type systems for a couple of reasons, and they also work better with traction control on with our cars

There you have 3 options,
- a x300 diff(iirc) but requires some modding to make it fit (but doable),
- a unit from gripper diffs (they build it into the diff housing for less then the Quaife unit alone)
- or one of the best but also the most expensive one the OS Giken TCD unit which I use now. OS Giken also sells the Neo version which is closer to the quaife in price.

 

Is this the nicer one?

OS Giken Super Lock LSD for JAGUAR XK Series X100 1996-2006 (Spl Black Case) [OS EDO Performance

 

Now the million-dollar question; which one is better for launching at the drag-strip?

ATB or clutch-type?

 

The Superlock is discontinued already for some time, so it’s either the TCD or NEO version, where the latter is probably closest to the old Superlock. So I guess this is old stock, or an outdated site.

 

The OS Gilken site doesn't list Jaguar as supported. Is there a specific model that bolts in or is there machining required to fit it?

 

This is how I ordered mine (which is a direct fit):
8708.40.5000 TCD for Jaguar XKR 1.5way Spec-S

 

That's outdated. There is a new part, a dealer said that they actually haven't produced it yet or that it was built to order... or something. It sounded like he mentioned something about the distributor not having had that part in before and that he was calling Japan later today. I had trouble understanding what he said, he had an accent and the line was bad. I'm awaiting more info, but sounds like the NEO unit I'll be buying.

This is going to make driving my Jag a lot more fun. And I'm buying this in preparation of the twin screw upgrade, which I plan on doing sometime this winter.

 

Have no experience myself, but I would tip the clutch type. One of the advantages here is that you get a 100% lock (with the right clutch system, like the OS Giken), meaning you will go in a straight line. ATBs seem to have the tendancy to fishtail. Also any rear end brake out is much more predictable and easier to control with a clutch type than with an ATB one.

Here is a comment from OS Giken:
"In essence, the Spec-S will feel like an open differential that doesn’t allow for unwanted wheel spin when exiting corners or “tail wagging” during heavy straight line accelerating (as the unit will provide progressive locking at equal rates to both wheels due to the centered design of our unit). For drag users, this will translate to greater straight line acceleration and keep the rear where it is supposed to be"

How that translates for our cars in speed on a dragstrip I can't tell.

An ATB has its advantages, and this is not to put that type down, and I think for most moderate drivers this is an easy one to drive with. The clutch types are more fun to drive (and more involving which I like), even with traction control on, as you can take short 90 degree turns very fast (ie a T crossing), where with an ATB the ECU will immediately pull power quickly, which could be dangerous.

 

The NEO would indeed be the replacement for the Superlock (have double checked with OSG), try to shop arround for a good price, but I heard they have for the moment only the TCD in stock.

 

The Gripper diff site has information on ramp angles for clutch type limited slip differentials. If you dig further, then you find out *how* ramp angles affect on throttle and traliling throttle handling characteristics.

 

Hello chaps! As an off-shoot of an new thread I posted today on your XK forum: Recently, the S-Type forum purchased a salvaged Gen II differential ($100) from Euro Chop Shop and shipped it to Drive Train Specialists (DTS) in Warren, Michigan. Here they'll fit it with a LSD using the stock 2.87 gears. Unless we overcome the TCM gear ratio limiter, any other ratio will throw it into limp mode. Any Jag (S-Type, XJ, XK, etc.) can send their carrier to DTS for fitment of an LSD with the stock or lower gears. DTS mentioned it'll come with a LSD, new seals and bearings, costing in the neighborhood of $800 (they indicated a group buy of $700). A place to start is for the XK forum to ship a salvaged differential to DTS and....

 

I had bus my QDF5W for my XKR MY 2005 from Equipe Torino - Vendita ricambi e accessori per motorsport.

 

Welcome here ;-)

The diff carrier of the 1996-2005 XK8/R (so steel version) is very different than the ones for the Stype, the aluminum bodied (so 2006 and up), has the similar carrier, so better to post on that forum as well.

Never the less, the carrier is slightly bigger so they may as well be able to offer different internals than currently available, so good to mention here as well.

 

Thanks Avos. IMO, anyone can send their carrier, regardless of its composition, to a drive train specialist to discover the possibility of an affordable alternative to the Quaife LSD. In the meantime, the S-Type forum eagerly awaits word from DTS.

 

Agree, it’s good to know if there is a specialist who can build these diffs, as the life of the diff depends largely on how well the diff (/pre-loads) are setup. Taking shortcuts there can be costly...