Picked up my LS's sexy British cousin, looking for rear end upgrades

[Ranchero50]

So, after having my '05 LS taken / bought from me by my son I went Mustang shopping and ended up with a '07 Jaguar XKR a couple months ago. 4.2l V8 with an Eaton on top making 420 hp and torque. I got it for about 15% of it's $86k new price and it needed some love.

Naturally there is a rebuild thread:

'The Green Turtle' or 'Lets Fix This Junk' - Jaguar Forums - Jaguar Enthusiasts Forum

The car is built very similar to an LS except it has an aluminum monoque frame and steel substructures where the LS has a steel frame and aluminum subs. It's also been blessed with the 8" Ford differential and I'm trying to find threads on swapping a 8.8 into it's place.

Thanks,
Jamie

 

[grizzlyls]

Grats, ya I noticed British racing green right off. Best choice IMO. Read the story to understand the 'Black' lol. Only thing I feel they could do to make it sell better is metalisize (or 'frost') it like most cars go now, but that wouldnt be tradition of course. Don't know why you want to swap rears, dont think the bigger size is going to be needed for strength, IIRC my supercharged 302/351W (block/heads) Custom 84 Ranger had 8 inch on 35 inch tires....

 

[cammerfe]

I'd look at the 8.8 available from a Mark 8. It's a semi-bolt-in for a first-design LS and will probably not be much harder to put in your 'Cat'. Has an aluminium (note Brit spelling) carrier and limited-slip is available.

KS

 

[DeviLSh]

Doesn't quaife offer a jag specific drop in now?

QDF5W

 

[DeviLSh]

Oops, didn't realize yours was 07 before linking that, sorry

 

[Ranchero50]

Doesn't quaife offer a jag specific drop in now?

QDF5W

Yeah, it's pretty expensive, $1600 or so. Looks like the Jag '07 is the same as the 2nd gen LS carrier just has an aluminum cover with cooling fins and an air scoop. The Quaife unit is the only one that fits. Kind of a bummer because off the line the car really needs a locker, especially if there's a turn involved. The traction control is very harsh and pulls a ton of power out. There's a couple 1st gen LS's in the local yard so I may go get them to flip one over so I can pull the suspension out. The 1st gen S types are similar and from what I've read will fit. If I had a spare 2nd gen I'd pull it apart and see if I could machine a new locker module that would fit the housing.

PITA...

 

[DeviLSh]

No matter how you slice it, you are looking at a decent chunk of time, parts, or coin. Reliable, fast and cheap - pick 2 because you'll never get all three!

Started picking parts up for my mark8 swap in my gen2 last year and am still not done. I am probably $1,000 or so in parts before it can go on.

 

[1LoudLS]

Started picking parts up for my mark8 swap in my gen2 last year and am still not done. I am probably $1,000 or so in parts before it can go on.

are you also looking to change the rear end gearing in the car?

 

[DeviLSh]

Yes, 3.90 or 4.10 most likely. Trying to decide if I want to go with a Ford LSD (OEM rebuild) or something aftermarket, I need a balance between drag and handling.

Subframe, mk8 housing, and gen1 LS rear cover acquired. Need R&P, LSD & Diff, and gen1 Axles still. Oh yeah, and the custom driveshaft adapter for the mark8 yoke. Going to do new rear bearings at the same time (might as well) so this project just keeps on going!

 

[XJLS8]

Congratulations. Such nice cars Jaguar engineers. As far as an 8.8 swap im not at all trying to talk you out of it but the factory rear the Jaguars come with in your generation are stout and dont really need any upgrading unless you desire a 700+ horsepower car on drag slicks. As far as a limited slip or locker I will personally say give a decent set of tires a try before thinking its the open differential throwing an abundance of power to one wheel thats your traction issue.

5-6 years ago I had an 04 XJR. The 4 door supercharged Jaguar. I had 443hp to the flywheel from a few supercharger/intercooler upgrades. I ran the factory rear end open differential with 2.87 gearing. Same ZF6 transmission as the XKR with the same shift points between the two cars. Weight is also near identical between the two cars as well as the weight distribution front to rear. With a set of Pirelli P Zero Rosso sport touring tires that car hooked up and ran a best of 12.9 in the quarter mile. There was nearly no wheel slip with the traction control off and a 2,000rpm launch.

Just my .02 I do hope you enjoy and have nothing but positive experience with the car and look forward to which path you do end up taking.