My 2008 XK convertible definitely dives too far into fast road undulations and doesn't recover quick enough for my driving style. I'm assuming the dive has to do with softer spring rates and the lack of quick control of the rebound has to do with the shocks.
Correct me if one has a different take on this situation.
Due to finances (lack there of) I'm temped to try and find a set of four springs/shocks from a wrecked (low mileage) XKR. I cannot find new springs in the after market that aren't 1"+ lower than stock...this won't work on my roadways.
If someone knows of an after market spring maker, please chime in.
thank you
wj

 

Look before you leap. I don't know for sure, but I doubt that it's a simple swap as you may think since the XKR suspension is electronically controlled. I suggest that you go to the Sticky Threads at the top of this Forum, click on the Sticky for Workshop Manuals and Electrical Guides, and read about the differences between the XK suspension and the XKR CATS suspension.

Your XK is 14 years old. If the rubber suspension bushings are all original, they probably need to be replaced. Sloppy handling could be caused by worn bushings, and your shock absorbers might be OK.

 

Thanks StuartS,
I thought all x150s had CATS. Never the less, mine does have CATS.
I'm 99.99999% certain this isn't a bushing issue causing the bouncing (or lack of rebound control). The handling is tight, not sloppy.
BUT
when pushed the car's springs are compressing more than I like and there doesn't seem to be much control of the rebound before going into another compression cycle. If only a single turn at speed it is fine but if that turn is followed by a switch back the softness is quite unnerving as the car somewhat rolls into the other turn. Image pushing a big ole Olds 98 that has the best aftermarket suspension available, you can only do so much with the antiquated suspension design and 2.5 tons of mass. The XK isn't that bad but it wants to float.
So, do you know of any aftermarket springs available for this car, that don't lower it 1+ inches?
wj

 

There are a couple options. Yes the XKR spring is stiffer (firmer) and you should notice a change. To call it an improvement would be for you to determine.

Both Steve_K_XK and Jahummer have recommended BC Racing coilovers in the past.

 

All X150's have CATS. The 4.2's have a binary system (hard/soft). At some point, I think with the 5.0's, they evolved to a much more complex and variable CATS system. Both are described in the Maintenance manuals.

 

Doesn't Bilstein make a stock shock upgrade for the XK with CATS (& all the other Jags too)? Might be worth checking it out

 

@wymjym I like how you described the role of springs vs shocks.
Perhaps the cost of racing coilovers (and the added performance) is not suitable for your needs…. But I would also warn you about purchasing an used set…. metal fatigue and settling does occur in the springs, seals do wear in the shocks; and your car is as old as mine. That’s why I have completely replaced my suspension. Had you ever done that?

 

They've OEM replacements certainly but no aftermarket upgrades. There was some talk of Nitron and Swallows Racing offer some and of course there's BC Racing.

 

Agree with Jah on this. Lots of discussion on Bilsteins in the BMW world.

They are OEM for many BMW's as well as our X150's. The Bilstein branded Jag CATS shocks are in the B4 range. These are typical OEM grade -- decent quality, but the low end of Bilstein's quality range, with a service life around 70-100K miles. The B4's are not considered long life at BMW.

The B6 and 8 are progressively higher quality, but also harder ride. I can't find a B8 version, even for the B4 non_CATS strut.

The Bilstein product catalog shows the following part numbers for the X150 as being B4 class -- BUT since these must have been made for the Jag CATS, they will have different construction that the usual B4's. How much different, who knows?

And here's the url: Passenger car

IMPORTANT: I don't know if the CATS replacements below are for the two stage 4.2 system, or the multistage 5.0 system, or even both. Confirm before buying.

Also, it would appear that it's possible to install non-CATS struts in place of CATS. Again, doublecheck fit before buying. Also, I'd assume I have to code out the CATS system, and no idea if that creates other problems.

 

It is tough to compromise when you’re not the compromising type!

I have other more pressing things to handle at the moment, so I’m going to continue a search for a low mileage set of xkr springs/shocks (under 50K with no signs of leakage). If I don’t find a set by mid-March I’ll purchase new bilsteins and then if need be look for springs.

I will upgrade the sway bar bushings soon, that should lessen the initial turn-in roll a bit. I know that replacing all of the bushings etc would tighten this cruiser a lot but this isn’t the Jag of my dreams, although I really like it a lot. Visually only two of the bushings look as if they are worn much and they wouldn’t account for my bouncy issue.

Thanks for everyone’s input

Happy Holidays to All



wj

 

Well, it's also a price thing. 07-09: Jag PN: C2p3132: Bilstein PN: 20-114411 Bilstein OEM with CATS about $325 or so.

Bilstein with CATS Genuine Jag $475 (Rimmer Bros) to $777 (Jag Palm Beach).

All basically the same thing.

I pulled apart the Jag strut suspension. Very easy to work on -- actually easier than BMW's.

Add about $100 for the 2012 CATS, non SC. Can't find a clear Bilstein cross ref for the Jag C2P17670, CATS 10-15

 

you pay for a full set of 03-08 s-type b4s and send them to bilstein to revalve them to b6 or b8 spec

their center is constantly flooded with b8 shocks sent to be revalved back to oe spec

 

Sorry trying to decipher
...are you saying the b8 is too much for the street?
and has anyone tried to have the xk cat shocks send back for a revalve?...sounds like an phone call to bilstein is in order.
wj

 

for most people yes.

they don’t revalve most damptronic (cats) shocks or any original equipment shocks.

it has to be an aftermarket bilstein with a sticker on it.

 

A number of folks who wanted to further sportify their Bimmers went from OEM B4 to B8's, then right back as their felt their spines were getting shortened.

I Imagine it would be like having CATS in default hard mode.

 

they can and used to up until a couple years ago. they just don’t want to deal with any OE stuff.

call every shock rebuild service till you find one that says yes

 

In the UK CATS was a £995 option when the XK first came out so there are probably a few around without it. The non CATS shocks are also listed in the parts manual.