Hi, I am considering a set of used XKRS springs for my 2010 XKR. As the XKRS springs are stiffer, I am concerned about the stock XKR shocks not being able to properly control the added spring rate, and resulting in a compromised ride.

I know that the XKRS shocks are a different part # to mine, so I assume that they are either different internally, or just have different programming. Does anyone know for sure?

Has anyone done this spring swap, and if so, results?

Thank you.

 

The 5.0L XKR shocks are Bilstein B4's (green), the XKR-S ones are Bilstein B6's (yellow).

The CATS adaptive damping (Bilstein Damptronic) in them works the same way. You can fit XKR-S shocks and springs to an XKR and they "work" just fine.

A friend of mine has done the complete swap of XKR-S shocks and springs into his 2010 XKR, no complaints about the ride quality.

I put a set of 4.2L XKR-S springs & shocks into my 2009 XKR, it made the ride very firm, almost too firm for my liking... the Eibach-made rear springs on the 4.2 XKR-S are a very different design to the 5.0 ones though...

 

tnx cambo, but that was an xkrs spring AND shock swap on to an xkr. has anyone done just the 5.0 xkrs springs on the 5.0 xkr with stock shocks?

my objective is to see if the stock 5.0 xkr shocks will properly dampen the stiffer 5.0 xkrs springs.

thanks!

 

To be honest unless someone has done it, and happens to reply to this thread, the only way to find out is to try it.

I don't see the proposition being much different than putting aftermarket springs on the XKR shocks, and plenty of people have done that.

 

yes, you are correct, and I was one of them (H&R's on my 2007 XKR) and they worked well. The problem is, those springs were the same rate as stock, so they worked with the stock shocks. Unfortunately, no one makes springs specifically for the 5.0 XKR that have a stiffer spring and different dampers than the 4.2 XKR's. So basically, if one now installs the H&R, Spires, etc., springs, they will be too soft for the 5.0 XKR's.

Basically, the only option to lower the 5.0 XKR's now is with the XKRS springs, but the drop is also only 10mm, which doesn't seem like it's enough to warrant to expense and my time installing the. I was looking for at least a 15mm drop.

 

What's the actual question? Springs hold the car in the air, shocks control the ride. What are you trying to do with different springs?

 

[QUOTE=Ranchero50;1803878]What's the actual question? Springs hold the car in the air, shocks control the ride. What are you trying to do with different springs?[/QUOTE

yes, you are correct about that, and I am well-aware.

I also am well aware from experience (and physics), that a spring can be too stiff for a particular shock, and therefore, you will lose control of that spring. at that point, one is riding primarily on the spring alone, with little to no shock involvement to control the ride.

what I am trying to accomplish with the xkrs springs, is simply to lower the car. as no one makes a lowering spring specifically for the 5.0 xkr's (only the 4.2's), so my only proper option for lowering is to go with the xkrs springs, although the drop is only 10mm.

my question is simply this.....is the higher-rate XKRS spring able to be controlled properly and adequately with the stock XKR shock.....

 

Are there physical differences between the springs for a 4.2 and a 5.0?
The shocks appear to be the same size, so if the springs are, maybe you can use a 4.2 lowering spring on your 5.0?

 

the stock springs on the 5.0's are considerably stiffer than the 4.2's, and it makes handling MUCH better (have had both cars), while not hurting the ride quality much, if at all. I don't want to go to a softer spring, which I would be doing by using the 4.2 lowering springs. jag/bilstein also made considerable changes to the 5.0 shocks, over the 4.2's, and they are calibrated/programmed to also work with the stiffer springs.

 

The attached is from an interview in the August 2011 Jaguar World with Dave Pooks, JLR Technical Specialist, Vehicle Dynamics.