My car is the LWB Supercharged 4.0 V8 with CATS suspension. It also has very soft rear springs of which one has just broken. I want to order replacements but am confused by the options and hoping that contributors here might be able to guide me. I’ve searched but don’t really have clarity.

There are three options on the SNG Barrett and JLR Classic sites (always my initial go-to’s). There are:

JLM12257 - another post mentions these are what to go for but that doesn’t feel quite right. SNG and JLR say that these are for comfort suspension on non-supercharged cars and don’t mention adaptive suspension. JLR does mention that they’re not for “ride level system” (is that the same as CATS).

JLM20589 - stated for 4.0 supercharged cars with sports suspension and “ride level system”. Berkshire JAG says that these are for supercharged cars with Sports Adaptive Damping. They also appear to be the springs for contemporary XK8’s

JLM12342 - appear to be for non-supercharged cars with sports or comfort suspension and without ride-leveling.

Common sense tells me that I need to order JLM20589 but the lack of consistency in the terminologies introduces doubt. Also, does the Super V8 with its limousine pretensions have “sports” suspension?

Any guidance or, indeed, alternative suggestions would be much appreciated. I can then go and source some….

Cheers

Mark

 

Common sense (which is rarely common, today, in the Colonies!) wins!

 

I was going down this same path about 18ish months ago on my 03’ SV8. I have 50k mile XJR rear springs that have been off the car since 2011. I put the green sports CATS shocks on all 4 corners. When I had both rear sets of the XJR and SV8 rear springs out and side by side, there was a discernible height difference. I wanted to put them in but, I didn’t want the *** end down and the front end stock height. No Carolina squat or low rider here. I can’t imagine Jaguar would’ve offered sport suspension for a LWB car but, I really don’t know.

 

All three springs are not for ride levelling system so you can leave it out of the equation. The ride levelling system (not same as CATS) at the rear was optional and it appears that not many X308s came with it. The springs for this system are JLM12311. Otherwise, there is no difference between springs for CATS (Adaptive Damping) and NON-CATS suspension (the difference is only in the shock absorbers).

Extract from the parts catalogue showing the application of the three types of springs:

 

Thanks for all the input. I've done an extra level of reading and worked out that my car has comfort suspension. It was simple, really - the sports suspension cars have a rear anti-roll (sway) bar and mine doesn't. I'm thinking now 12257...

 

Well, what is left for interpretations in the parts catalogue is the statement that 20589 is for "4.0 Litre supercharged". It does not say that it is for XJR (only) and, since Super V8 is also supercharged, it may be interpreted to mean that this spring is for both and that the other two springs are for NA cars. On the other hand, one can interpret that, since Super V8 was built for comfort, the springs specified for "supercharged" are for XJR only and not for the Super V8.

 

M, that makes sense but, the LWB cars weigh more and will likely sit lower than an XJR. How much lower is the question.