That's right, to install the Quaife in my XJR there was no modification needed, it bolted straight in. Simple.

But after that, Seth keeps asking; "does it fit the STR? does it fit the STR?"

Well look fellas, AFAIK the housing is the same for the STR and the XJR, but i'm not gonna tell you "yes it fits the STR without grinding" because Murphy's law.

Tom Lenthall was very helpful by email & assured me that the Quaife would fit my 2004 build XJR without modification, so long as the original diff was fitted. It was, and it did. So write him an email & ask him about your STR...

 

If there was an OS Giken available (or any other clutch type LSD) that was a direct fit, I would have bought it.

The Quaife, expensive as it is, was the only guaranteed off-the-shelf bolt-in solution available for my car.

Now, looking at the pics of the Quaife installed in the XJR housing, I really have to wonder why nobody has been able to get an 8.8" LSD in there....

But doesn't matter, i'm done now. Even if a clutch-type LSD becomes available i've already spent the money...

 

Yes. The Lincoln Mark VIII guys like this aftermarket set of bushings for the rear diff. There have been some seriously fast Mark VIII's built so a lot of aftermarket things are out there.

Lincolnmotorsport.com - Mark VIII - Driveline
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LOL! Cameron, just say it: "The XJ and S-Type share the same differential thus we have good reference that the Quaif LSD fits the STR case without grinding", and leave worrying about Murphy's Law to us.
Now, in regards to the above statement and a Quaif LSD, is it safe to say it will fit an STR's diff. case without grinding?
All other LSD won't fit our case due to the design of the LSD not being offset to accomodate the axle halfshafts. The case can be grinded to accomodate a 8.8 Traction-Loc but would neceesitate custom axle halfshafts.

 

Only way to be sure is try it. Did the STR article in JWM refer to some grinding? Or call Tom at TL Jaguar as it was him that put a Quaife in an STR.

 

Still raining & cold here, but I took the chance to try out the diff anyhow.

Launches are much much better now, can hold my foot to the floor with DSC off & just let it sort itself out, very nice. If I ease into it off the line it just hooks up & hauls ****.

It's a bit jittery at times (when putting the power down at corners from a standing start) but it's hard to judge until I can try it out in the dry.

It has transformed the car, for the better.

 

Cambo, is the LSD quiet?

 

Haven't heard any noise from it, totally quiet.

 

The corner launch is awful in my car now and engages the "system" in a herky jerky fashion so I'm hoping that this is much better no????

Still, I have a Torsen on another car of mine that's twin turbo, light in the rear and the torque comes on like a sledge hammer. The Torsen doesn't tame that one perfectly either. It can't work miracles. Ediff ...

 

Have you taken a look at all of your control arm bushings to see that they are all intact and haven't started to fall apart? This miight be part of why the car is experiencing the jitters. Too much play in the suspension.

 

Its these tight turns where you apply power thats most difficult, as the traction control kicks in there. Then the quaife unit might work against the traction control. So when the car is braking the wheel that needs to slow, and the quaife unit sending automaticlay the power to the wheel with the most grip...

Not sure of course if that is the case, but you might feel a difference with the traction control off.

This is also one of the reasons I have a clutch type now, there I don't have this issue, and can take the 90 degree take offs pretty fast, even with traction control on slight sipping of the wheels ;-)

 

OK so I did 500kms yesterday, up to Stuttgart & back on the Autobahn, with a few excursions on the back roads, finishing up with a run through the hills on some very tight twisty mountain roads. The long run was to try & sort the fuel trims out after fitting the smaller pulley, as well as a shakedown before going to the 'Ring next weekend.

Joe, I had all the suspension checked while the diff was out, bushes are all good & tight, so that's not it.

The jitteryness was much less noticeable in the dry yesterday. And yes Andre I think a lot of it is to do with the DSC. Instead of cutting engine power like it used to, it seems to be braking the rear wheels individually more.

Also, in the wet you obviously have less traction, so I think the jitters was actually the tyre slipping on the pavement, without completely breaking loose.

In the dry yesterday I could get the back to step out completely (haven't done that in years) and it was quite a smooth action. Obviously that was with the DSC off.

In fact with the DSC off the drive is very smooth, even while breaking traction, on those 90° standing starts.

With the DSC on you do get the feeling that it's a little confused. But you just need to adjust your driving style accordingly.

I'm happy with the way it works, a million percent better than the open diff.

I had a little moment coming through a roundabout, the back end broke completely loose at only 2/3 throttle, but it was very controllable.

 

This is exactly my interest in installing this unit. So why do you think the clutch based unit is going to work better with the DSC turned on than the Quaife?

What's the technical explanation. Just saying it has clutch plates isn't a clear enough reason for me?

Turning off the DSC will eliminate this but I'd prefer to have it on for normal street driving such as when my wife is driving the car. She's not going to appreciate having the rear swing out when driving the car.

That's of greater appeal to men anyway ...

 

If you are driving normally or with moderate throttle inputs, you don't notice the Quaife at all, by that I mean it does it's job. It's only until you go a little harder that the DSC intervenes. Compared to the open diff you can certainly get more power down before DSC engages.

Technical explanation is beyond me. But Quaife make a point of saying "an ATB never locks" whereas a clutch-type will lock when both tyres break traction.

 

I don't know exactly how the software works of course, other than it measures the difference in speed between the wheels. With a clutch system (and pushing it), you get less difference in speed between the rear wheels, and this allows you to go faster thru these corners with traction control on. Another benefit is that a slide (so if you have turned of the traction control accidentally), is much more controllable then with the quaife. Again the quaife is a very good unit, much better then stock, so am not bashing it, its an easy diff to drive.

 

Eric of DTS left me a voice message: He buys the Quaif LSD for $1375 and installs for $240 for 3 or more Forum members or $200 for 4 or more members. But if it's just a drop in LSD, then why bother? How much $$ is a Quiaf LSD?

 

Uhh... about $1,400 I guess? plus install... not too bad... might be worth it for some... me? I have a street'able track car with an OS-Giken, so not sure if my daily STR absolutely needs an LSD at that price....

 

Agree. My 03 STR rips em up and punishes without it. NY roads suck so much that hardly anyone want to do the twisty competition thing. I'll put the $$ in an ETG ecu tune.

 

Quaife center £695 = $1060
Bearing/seal kit £195 = $298
Delivery from UK £80 = $122

 

You live out on LI right?

When you can escape the NYC metro area and head for the hinterlands then if you're pushing the car hard in corners or in the wet you'll be glad to have it.

My stupid traction control engages more often than not when I exit my development going up hill due to a certain set of bumps. It's a very steep hill.

Just pisses me off.

Those prices don't scare me but I think I'd rather just turn the entire job over to my local guy. Ant bring it back issue will be so much easier.

I have no home shop at the moment.