Once again i am still in the hunt for a lowering kit... anyone know of anything.. i emailed arden they said there making something.. mina is in testing...

 

Aren't the XJs on airbags?

 

I don't know the exact setup of the suspension (I have not looked under my car, yet) but, I would dare to make a guess to answer your question.

Airbags (if used) are likely used only for the ride leveling feature of the XJ. If that is the case, the car would still have conventional springs and dampers but, have airbags that inflate/deflate automatically to raise/lower ride-height in the rear.

Albert

 

On the x351, it has conventional shocks/springs in the front and airbags in the rear. No conventional shocks or springs in the rear.

 

OK so in that case, you need to find lowered springs for the front, and have the ride height re-programmed at the rear. Same as https://www.jaguarforums.com/forum/x...ur-x350-75369/

Fronts are a bit more complicated, yes it seems there is no aftermarket source for lowered springs.

I see two simple options;

1. Cut a coil out of the stock spring
2. Try fitting the springs from the 3.0L model, since they are probably setup for less weight over the front axle.

Might not be great for the ride/handling though...

 

That's what i thought.

 

Hmmm.... my car is at the dealer right now with ride quality issues and the service manager said that there was a code in the car indicating a "Rear Damper Solenoid" failure. That would tell me that there are shocks in the rear. Actually, I can not imagine what would be doing the dampening without shocks. But, I am making a NOTE to remind me to ask the service guy when I pick up my car later this afternoon about springs/dampers/airbags on the rear. Will let you know what he says.

Albert

 

Unless your X351 happens to be an armoured Sentinel, you will have airbags in the bag.

 

I haven't removed the suspension on my car but from what I can see from the rear wheel wells, it appears to be similar to the older x350 models

pics of the x350 rear air shock -> https://www.arnottindustries.com/ima...1_20110501.jpg

 

So, the verdict, according to the Dealer's shop foremen is:

Indeed the rears have no springs but, they do have conventional, electronically controlled shocks that are part of the airbag/damper unit. They are fluid-operated dampers and, according to him, the solenoid that went bad on my car was actually not regulating by opening and closing a valve thousands of times/second (as a fuel injection solenoid would) but, by changing the diameter of the valve orifice. Interesting, wonder how they accomplish that?

As to the question of lowering the car; looks to me that with the lack of rear springs that would not be possible. You probably have to find someone to manufacture a coilover adjustable spring perch setup. Personally I would not advise giving up on the electronic damper controls which make the ride on these low profile tires livable.

Albert

 

Just wondering if 6 years later anyone has come up with a solution or if any companies have come out with a custom airbag setup allowing for adjustability in these cars?

 

The rear ride height can be calibrated / adjusted using the dealers diagnostic tool. The rear ride height is already adjustable if you have the right tools and know-how.

The problem is the front springs, nobody is making a lowered spring for the XJ to my knowledge. There are probably some springs from another model; XF, XK, etc that will fit & work but that needs some investigation...

You could go a full aftermarket bagged system too, there are a few XF's on custom bagged setups.

 

There are multiple companies you can find online that will wind custom automotive springs and the cost is actually quite reasonable at around $200 to $300 a corner. People build race cars, hot rods and customs out of all sorts of unique and rare cars all the time, they do lots of custom springs for wheelchair vans, limousine and hearse conversions, etc. But unless your vendor has made X351 springs before and has the specs on the stock springs in their database, you will have to remove the stock springs and send them in to be measured and tested first. And they may ask you to get the corner weights on your car. Once they have the stock spring specs and weights, you tell them you want it an inch lower, inch and a half, a little softer/firmer ride, whatever. They run some calculations and determine the specs to wind the new spring.

Of course with any electronic controlled suspension, you have to research first to make sure that whatever you change won't upset the computer and I'm sorry I know very little about the X351. You want to be careful as if you change the spring rates very much you might need custom dampers too plus you also want to be careful that the tires aren't going to rub and that the alignment isn't going to exceed the adjustment thresholds. These potential pitfalls tho are why obviously it'd be great if there were an already developed aftermarket "kit". If you want to proceed with custom springs, I'd suggest talk to an alignment pro at a competent indy Jag shop first.

Our base and Portfolio XF's tho are relatively easy to mod since adaptive suspension was only on the R. One of the reasons (besides the sheer size increase) that I updated the X308 to an X250 instead of an X351 because I knew I could relatively easily get back "some" of the magic carpet ride with a kit from Spires. When I was young, sports cars all came with a compromise suspension for on-road comfort and I always had to modify my race cars. Ironic that now that I am old and injured, every luxury car comes out of the factory race-ready and I had to modify a "sport sedan" for comfort.

 

there is a company called AirRex/AirRexTexas that makes a kit for our cars, but I dont really understand how it works, since only the rear is air:

09-17 Jaguar XJ - Airrex Digital Air Suspension System - Airrex Texas

Ive also thought that maybe the XJR sits lower than the regular XJs, and the front springs do have different part numbers, but i dont know how much lower it actually sits.

 

Oh man...this car is low enough already, especially with the Speed Pack front bumper attachments! I'm always scraping that damn thing.

 

XJRs suspension is different. Here is excerpt from the 2014 product brief when the model was introduced to North America
The dynamic characteristics of the XJR are the combination of:
1. Enhanced front and rear suspension system, carefully tuned to optimize body control,
balance and composure while giving the car a greater feeling of agility and providing a more
overtly sporting character.
 Front spring and rear springs stiffness increased by approximately 15% and 10% respectively
to enhance control and high speed stability
 Revised steering rack assembly and new antiroll bar to reduce body roll
 Revised steering hydraulics and calibration to enhance the steering feel, response and
feedback from driving conditions ;

 

well there goes that idea, based on the fact that it just simply says stiffer springs, and not a lowered ride height.

There was a member who i saw got custom springs made, like pdupler said, but there really doesnt seem to be an out-of-box option for the front. Even Arden and Startech dont seem to have their XJs lowered.

 

What about dropped spindles which would allow the front ends geometry to remain the same? Does anyone know if the XJ spindles can be modified in this way. Any sources?

 

I think that is FAR less likely. These are low production number cars so anything like aftermarket lowering spindles won't be produced.
Just no demand.
Working on the spring idea is simplest and as you can see we don't even have that yet!
.
.
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Hi guys,
I'm in discussions with a number of companies to get custom springs made to lower my xj.
Does anyone have the part number of the standard springs or any information on where I would get them without having to take this tandars springs off the car?
All the best,
DK