Ditto. Former S-Type forum member, Mafioso, had a Quaife LSD installed on his 05 STR. He returned to the tech a few times to improve pre-load. Eventually the rearend locked up. He sold the car shortly after. With the differential on a bench, the tech can more easily determine specs, etc.

 

The thing that I heard about the Quaife that I didn't like that is if you completely lose traction on one wheel, the damn thing may decide not to lock up and just spin one wheel.

Add to the fact the Quaife employee wasted two weeks of my time = OS Giken getting my money.

Quaife can go queef, as fair as I'm concerned.

 

A clutch style LSD would solve the uni-wheel spin...tighter lock-up.

 

So...DRIVE TRAIN SPECIALIST can or cannot do an XKR diff?
Thanks for all this information. With the prices involved I can't help but think of building a cradle for an American diff.? I've got tube benders and welders (TIG, MIG, GAS). I'm building a rock crawler out of my 1970 Ford Bronco, so.......?
Wayne

 

Why not, you may want to look for a full suspension system that fits almost close enough, Jaguar once made a one of XKR with a STR rear suspension. Maybe something like that could be an easier start, than to make one from scratch, as there is as far as I know not a American diff that is part of the suspension (so where the axle acts a little like an upper arm of the susp.).

 

Well if I did a rear suspension, I would fing a design the DOES NOT USE THE AXLE FOR THE UPPER SWING ARM. I had a Lotus Europa JPS S2 (Ford engine) and it used the upper axle as the upper link. I had a failure of the upper joint when I put on a HART BDA 2LITER, Turbo charged and injected. The failure involved a total rebuild which included a DG-500 and a reverse lower link and trailing arm off a Ralt.
If I did anything it would be to eliminate this "COST EFFECTIVE MEASURE".

 

This is the reply I got after my inquiry to Quaife.

Dear Wayne

Thank you for your enquiry

The Quaife ATB QDF5W is £895.00 and in stock, ready for dispatch. If you can supply a shipping address, I can give you a price for shipping

Best wishes

Martin Slade
01252 894785
Click here to visit the website
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The information contained in the email is confidential and is intended for the addressee only. If you have received this email in error please inform Racing Green Cars immediately and delete this email and contents from your system. If you have received this email in error you should not place any reliance upon it, or copy or forward any of it in any form. Racing Green Cars maintain current virus control software but does not represent this email to be free from viruses. It is the recipient's responsibility to maintain adequate virus protection and Racing Green Cars will not be held liable for any loss resulting from the receipt of this email. Racing Green Cars and Racing Green TVR are trading names of Racing Green Cars Ltd. Registered in England and Wales Registration number 4012195. VAT number 753 5345 26. Consumer Credit license number 496952. Racing Green Cars Ltd registered address Connaught House, Alexandra Terrace, Guildford, Surrey GU1 3DA.

 

I know that this is an old thread but the subject is the correct one. Looking for a LSD for my Xkr '00. The workshop first confirmed they can supply a Gripper clutch type LSD but today they called again after having received negative confirmation from Gripper themselves, they don't have a LSD for my VIN.

Does anyone know of a clutch type LSD that can be ordered for a Xkr '00? Otherwise I will go for a Quaife, but thats plan B

 

A possible option, not without its challenges, is going the HU15 limited slip differential route from X300 models, etc. - especially given the known weakness of the stock HU14 pinion/ring. Obviously it would be frustrating to spend the money, and then keep swapping in HU14 diffs if you keep chewing them up, depending on driving style and engine power. It is addressed in quite a few threads on the forum. This what I'm thinking of doing (when budget permits) because I'm afraid to mash the throttle at takeoff for fear of breaking the diff, and that's frankly unacceptable....

As far as I can tell the key challenges are:
- mechanical
- offset input shaft - need front triangular mounting plate from donor car to mount, also will the prop shaft clear the rear end of transmission tunnel in an XKR or does this need a solution as well? (seems to be OK on XJR...)
- possibly adapt coupling on HU15 input shaft (e.g. Jurid coupling) to match XKR prop shaft if necessary (likely not too hard)
- other issues?

- ratio/electrical
- not sure that XKR stock 3.06 ratio is available from HU15 (I think there are 3.27, 3.58, 3.77, 4.09)
- it seems you can rebuild the entire HU15 Salisbuy/GKN internals with Dana44 (per Count Iblis), and then free choice on ratios and various limited slip implementation options, and need to consider the spline counts on input and output shafts - gets quite complicated and expensive but a very elegant engineering solution
- or choose different ratio from HU15 (which likely gives more acceleration and less fuel economy) and deal with modifying, or spoofing input to, the transmission control unit
- I think, as others have proposed, that intercepting the canbus and modifying the ABS module speed output to TCM, but not to instrument cluster, would work. I've not seen any success story, but I am working to try it out. It seems getting a TCM reprogram, if you can find someone to do it, is fabulously expensive (I guess many Mercedes drivers have too much disposable income).

 

There is not to my knowledge a clutch type available as a direct drop in for the XKR. OSGiken was the best option but they have stopped manufacturing that model some time ago. Quaife is the best option short of replacing the diff entirely.

 

Many considerations to do here. The HU15 route seems the best long term way to go if I plan for a lot more engine power. But where is the limit of the HU14? Depending on driving style of course. My 4.0 Xkr is close to standard, the 10% smaller upper pulley, Milltek exhaust, Mina gallery intake tube and a K&N air filter. Maybe 400 hp? My driving style is semi-aggressive. Not planting the gas pedal to the floor everytime but now and then.

There seems to be a lot of work to make the HU15 fit, uncertainties as well. If there was a clear path to follow it would look more viable.

The can bus mods sounds interesting to me, having fiddling with an Arduino with a can bus shield this winter. Should be doable to modify the value before sending it to the transmission control unit. What comes to my mind is that by intercepting the bus signal you will delay the signalling speed by maybe 1/1000 of a second. Not sure how that will affect the bus

 

See this thread on canbus by crbass on canbus decoding
https://www.jaguarforums.com/forum/x...-no-sc-222041/I am guessing (maybe wrongly...) the trick is to modify the wheel speed reading so the TCM is unaware of the axle ratio change. The true value can still be sent to the speedo.
CAN bus ABS speed signal appears from the above (not an XKR though) to be 8 bytes, 2 bytes per wheel, Sent every 8 ms. Message is 8 bytes plus about 5 bytes overhead, so transmission time is 2 us per bit, or 208 microseconds. Interrupt service routine, leveraging MCP2515 to do low level processing to minimise overheads, would need to scale the value in these messages - looks do-able, plus I'm guessing there is not any explicit synchronization between the modules, likely only derived from the canbus signals, so a small delay probably acceptable. So delay would be 208 us to get the message, plus execution time of the service routine to get the data, modify, and schedule for re-transmission. Of course it can't be known for sure without trying it, especially if something else grabs the bus before it can be resent.....but but easy enough to make a repeater with a small delay without changing the values (i.e. write the firmware, but no change in the values), and seeing if the TCM freaks out before procuring and going to work on the mechanicals.

I'm planning to try it sometime with Arduino mini pro and a couple of MCP2515 modules. If Arduino not quick enough, then can upgrade to a quicker processor, but likely that the ISR execution is much quicker than the 208 us to get the original message anyway.

You can shot peen the HU14 pinion and ring, per Avos recommendation, and that would certainly help peace of mind. It's seems to be a game of chance on how well the diff was setup.
You can also avoid the TCM ratio change limp mode with a specific procedure on start up involving skipping through the gears in a certain way, as the ratio check only appears to be performed in the first minute of so of operation, but not very ideal for an everyday driver.


FYI some other threads for info on HU15 (not all of them, but a good cross section)

https://www.jaguarforums.com/forum/x...8-diff-212592/

Information from Andrew/Jaguar Specialities on adapting HU15 Jurid coupling to a 4 bolt custom driveshaft with Universal Joint. Also information from Motorcarman on the 3.27 ratio HU14 cars.

https://www.jaguarforums.com/forum/x...f-swap-141802/ Information from motorcar man on adapting a HU14 with 3 bolt Jurid coupling input shaft to work with XKR 4 bolt Universal Joint drive shaft

https://www.jaguarforums.com/forum/x...action-106568/

Jaxkr comments on procuring an HU15 from an XJR6 (X300 XJR) and matching front bracket, and using different input shaft flange.

ccfulton suggestion to intercept and change the Canbus messages to the Transmission Control Module

https://www.jaguarforums.com/forum/x...ar-diff-59936/

https://www.jaguarforums.com/forum/x...-thread-68571/

threads on challenges with the electronics, and replacing HU14 with HU15, and replacing internals with Dana 44 gearsets – Count Iblis, adam699, etc.

 

Wow.. that's an impressing collection of discussions in the subject

Agree on your suggested method of testing out the can message modding. I will be happy to contribute in that project. I use an Arduino Uno with a can bus shield from Seeed Studio. It has got both the MCP2515 and MCP2551 chipsets implemented. I have dug into the can messages sent in the bus of my Xkr 4.0 mapping them to the entities I'm interested in for my infotainment project

For my car this year, probably I will go for a Quaife or even just let the workshop change the leaking seals in the diff. I want to get the car on the road at least by end of May and then there is no time for another big project to find the HU15, solving offset issue etc. My original plans was just to change all bushings in rear suspension and sub frame.

But I would love to be part of the project of modifying can bus messages to the TCM!

 

Sounds good - car needs to on the road.
Also, if the TCM issue can be solved, you can go to a 3.27 ratio and stay on HU14 (I think using the 3.2 liter XJ8 diff?) if you want a bit more zip.

I'll post update on the concept as and when I have more info - limited time to devote to this as always.

I was thinking of doing a couple of datalogs on the can messages with timestamps specifically on XKR, to see how much the bus is utilised, especially around the ABS wheel message transmissions. I have the Sparkfun CANbus shield and SD card, but will need to write some code to do a capture of every message with accurate timestamps.

I've also designed a first pass PCB with KiCad for a Pro Mini and up to 3 can modules (cheap MCP2515 ones off ebay with SPI interface), the idea being to receive, retransmit, and monitor off board - waiting to get some samples back to see if the design is good. If so I could post the Gerbers if anyone else wants them.

PS if you are dropping the rear subframe, it's a great time to pull the tank since the fuel lines are right there, and replace the fuel pumps, if they are a few years old - much easier than working through speaker hole.

 

I finally got the Quaife lsd! Ordered two weeks ago and then there were issues with the shipping. Yesterday I picked it up and took it to the workshop together with a temperature sensor that will be screwed into the diff housing. More for fun than for real benefit. I'm working on a complete infotainment system for the car and there are lots of sensors in the car from where info on temperatures and stuff can be picked up but no sensor for the diff fluid temp. So I'm adding one

 

What model Quaife LSD did you end up buying? What type of LSD is it? How much did it cost?

 

I bought it via Ebay, same seller as for this item. I paid 999 GBP for it

https://www.ebay.com/c/1049282338

 

Got the diff back from the workshop! Quaife lsd fitted, housing sand blasted and painted. Also got a temperature sensor fitted. Mostly for fun, no intentions to build a race car. Have already done the programming to pick up the signal from the sensor and converting it to temperature.

 

Drooling with envy.

 

YES....drooling here as well....
forgive my ignorance, but... it would seem from reading here that this lsd modification does not change the factory gear ratio ?

many thx,

max & XKRFACE