Are X150 XK vs XKR CATS shocks interchangeable?

[Mike_Mac]

As per the title, does anyone know if the 2006 on X150 4.2 XK and XKR's CATS shock absorbers are interchangeable?

My assumption is yes, as the connectors look the same and I can't see Jaguar re-engineering a wholly different CATS system between two cars on the same basic platform, but I want to check first!

Anyone?

[8bit]

The part numbers are different certainly, whether or not that means a set from one model would not work on the other I don't know. IIRC the R sits a little lower than the XK so the springs will be different, at a guess that would mean different dampers to accommodate the difference in spring rates etc.

[Mike_Mac]

8bit said:

The part numbers are different certainly, whether or not that means a set from one model would not work on the other I don't know. IIRC the R sits a little lower than the XK so the springs will be different, at a guess that would mean different dampers to accommodate the difference in spring rates etc.

That's correct, the XK spring rates are a fair bit lower than the XKR's, so the damper rates would have to be correspondingly different for balance. I can't believe they'd have two different CATS systems for the same car, but assumption is the mother...

[8bit]

The CATS electronics will probably have to be programmed differently between the two models though. Probably the same hardware but different firmware.

What are you looking to do - is it that you're trying to fit a set of XKR suspension to an XK as an upgrade?

[Mike_Mac]

8bit said:

The CATS electronics will probably have to be programmed differently between the two models though. Probably the same hardware but different firmware.

What are you looking to do - is it that you're trying to fit a set of XKR suspension to an XK as an upgrade?

Ironically the other way around. I live in Devon. The back roads near me live in the 1800's. I really don't like stiff suspension or massive wheels as it's massively counter-productive on those sorts of roads (I know - why buy an XKR!!).

I've got a (very) cheap used set of XK springs/dampers coming which I plan to try just to see what difference it makes. If it doesn't work with the CATS then I'll not be out by much, but just thought someone may know the answer.

[8bit]

I see

So looking at the parts catalogue, I only see that the adaptive damping module part numbers change due to VIN number ranges, they are not listed as specific to any particular model of the car. It would take a bit of work and you'd need to have the JLR SDD diagnostic/programming software but it should be possible to figure out how to replace the firmware you have now with that from the XK.

By way of warning though, if you swap the dampers etc. in now and the module takes a dislike to them then it defaults to "hard" mode so until you can sort the programming out you may find you're worse off than you are now.

[Mike_Mac]

8bit said:

I see

So looking at the parts catalogue, I only see that the adaptive damping module part numbers change due to VIN number ranges, they are not listed as specific to any particular model of the car. It would take a bit of work and you'd need to have the JLR SDD diagnostic/programming software but it should be possible to figure out how to replace the firmware you have now with that from the XK.

By way of warning though, if you swap the dampers etc. in now and the module takes a dislike to them then it defaults to "hard" mode so until you can sort the programming out you may find you're worse off than you are now.

We'll see, but I don't think the firmware will be different. As I understand it, the early CATS in the 4.2 XK/XKR was a fairly basic 'it's on / it's off' affair, with the shock being switched on or off by the application of a voltage from the control module. Therefore, so long as the voltage is the same the action of the shock should be the same, it's just the valving of the XK vs XKR means the effect will be different.

Soon see.

[Mike_Mac]

In answer to the question, I can now say, Yes!

Fitted each shock in turn to one of the connectors in the engine bay and no issues.

[8bit]

Mike_Mac said:

In answer to the question, I can now say, Yes!

Fitted each shock in turn to one of the connectors in the engine bay and no issues.

So that is encouraging but I wouldn't be feeling like I was totally out of the woods just yet if it were me. My concern was more about how the system will react when it finds that the suspension in the car is behaving differently to how it's programmed to - there are sensors to measure movement, acceleration and suspension travel, depending on how the overall system is programmed it might interpret the variance as a fault.

Not trying to piss on your chips and hopefully I'm wrong, just that I personally wouldn't claim a victory until they're all fitted to the car and I had some miles done on them if it was me