How to lower your X350
#1
06-19-2012, 03:52 PM
How to lower your X350
OK so here is my take on how you can lower your X350 or X358.
I see three different possibilities;
1. Fit some longer rods to the height sensors (nothing available in aftermarket)
2. Fit some shims under the mounting brackets of the height sensors (this looks like it should work on the front, hard to say for the rear...)
3. Re-calibrate with a WDS, IDS or SDD diagnostic kit
First lets have a closer look at the air suspension system.
The ride height is fixed in the ASM, at the standard values from the specs;
Note:
Ride height is measured from the center of the wheel to the apex of the wheel arch, through the wheel center line
Note:
Ride heights quoted are as attained after the vehicle has been leveled using the Pre-Geometry function in Jaguar Approved Diagnostic Equipment. Once leveled, the figures quoted assume +/- 15mm anticipated build variance and condition
Note:
Ride height calibration can only be performed using Jaguar Approved Diagnostic Equipment
Note:
Due to diagnostic equipment calibration, metric figures are quoted only.
I don't know about you, but +/-15mm is a lot of tolerance!
I see three different possibilities;
1. Fit some longer rods to the height sensors (nothing available in aftermarket)
2. Fit some shims under the mounting brackets of the height sensors (this looks like it should work on the front, hard to say for the rear...)
3. Re-calibrate with a WDS, IDS or SDD diagnostic kit
First lets have a closer look at the air suspension system.
The ride height is fixed in the ASM, at the standard values from the specs;
Note:
Ride height is measured from the center of the wheel to the apex of the wheel arch, through the wheel center line
Note:
Ride heights quoted are as attained after the vehicle has been leveled using the Pre-Geometry function in Jaguar Approved Diagnostic Equipment. Once leveled, the figures quoted assume +/- 15mm anticipated build variance and condition
Note:
Ride height calibration can only be performed using Jaguar Approved Diagnostic Equipment
Note:
Due to diagnostic equipment calibration, metric figures are quoted only.
I don't know about you, but +/-15mm is a lot of tolerance!
There are several modes to the suspension; Sleep Mode, Preliminary Mode, Post Mode, Stance Mode, Drive Mode, Speed Lowering Mode, Towing Mode, Rough Road Detection, Leveling Inhibits, Jacking Mode, Inclination Mode, phew!
When it comes to lowering the car, the most important consideration is the Speed Lowering Mode;
- When the vehicle maintains a speed of 160 km/h (100 mile/h) or above, and 10 seconds elapse, the suspension lowers 15mm below the standard ride height.
- The suspension returns to a standard ride height when the vehicle speed decreases below 140 km/h (88 mile/h) and 5 seconds elapse.
So what this means is, you need to allow for this extra 15mm of height reduction when lowering the car. OK not everyone can legally drive at >160km/h, but nevertheless it should be safe if you ever get the chance, keep this in mind.
OK lets look at the height sensors;
On the very early X350's there is a sensor at each corner, after VIN G26872 there was only the one sensor at the front, with the two at the rear, as we discovered HERE
I'm still not convinced that this is the best setup, I would like to see a sensor at each corner, but anyway that's not the point of this thread...
I'm still not convinced that this is the best setup, I would like to see a sensor at each corner, but anyway that's not the point of this thread...
The front sensors look like this;
The rear sensors look like this;
They are bolted to the body of the car, and as you can see they have connecting rods, which attach to the suspension arms. As the suspension moves up/down the rods move levers, which rotate a rotary sensor.
The signals go back to the ASM, which tries to keep the front at 386mm, and the rear at 371mm (+/-15mm of course!) unless you trigger one of the other modes mentioned above.
Right so that's the background, let's have a look at the possibilities!
1. Extended/Adjustable Links on the Height Sensors
This is a popular mod on Range Rovers and Mercedes with air suspension.
The longer rods trick the sensor into thinking that the car is actually higher than it is, and so it lowers itself accordingly. Here is an example of a lowering link kit from a Range Rover Sport;
The longer rods trick the sensor into thinking that the car is actually higher than it is, and so it lowers itself accordingly. Here is an example of a lowering link kit from a Range Rover Sport;
The beauty of these is they are adjustable so you can fine-tune the height at each corner (yes RR's have a sensor at each corner, cause that makes sense!)
BUT sadly, nobody makes these rods to suit the X350...I looked into making them myself but I couldn't find the pieces off-the-shelf and I don't have the time/money/patience to start up a cottage industry here...
So, until someone comes up with the product, this idea doesn't help us...
2. Shims under the mounting brackets of the height sensors
Another trick from the Mercedes crowd, usually they just put washers under the brackets, apparently a 5mm washer = 25mm drop, or something like that. It kind of works the same way as the adjustable/extended links, you are just tricking the sensor into measuring with an offset.
I looked into this as an option, being nice and cheap, however I decided against it, because;
a. I can't get under the car easily at home
b. I'm not convinced that this would work very well with only one sensor at the front
b. I'm not convinced that this would work very well with only one sensor at the front
You are all welcome to try it, but I decided to pass and go for option 3..
3. Re-calibrate with a WDS, IDS or SDD diagnostic kit
The WDS, IDS or SDD as it's called these days is the dealer-level diagnostic system for Jaguar's and Land Rovers. You can't buy them at Autozone and they ain't cheap either.
I'm not going to elaborate too much more on the IDS, just how to use it to lower your car. Let's make another thread to discuss the machine itself.
It's basically, a laptop, with software and a special USB to OBDII interface;
You connect it up to the car;
And you can diagnose faults, change settings, and re-program the electronic stuff in the car. You can also calibrate the ride height.
So once you are connected up....
The car is scanned & identified, and eventually you can go into the Service Functions...
....where you have the option of Calibrating the air suspension.
You then have to follow the instructions; ignition off, on, start engine, wait, the system levels out and adjusts the suspension, you hear the compressor run and the shocks fill & bleed, eventually it levels out at what it thinks is the correct ride height.
Which is...front at 386mm, and the rear at 373mm, remember these numbers, they are important. If the car isn't sitting at this height, then it needs calibrating to the factory settings, then once it's right, you can go back in & start to lower it.
OK here is where you are meant to have the special tool to measure the ride height, looks like this;
I don't have this tool, so I had to go for the tape measure.
Not as accurate, but so long as you always measure the same way, it does work. Here's a tip, remove the center caps from your wheels, the growler (on mine at least) has a line exactly in the middle if you turn it 90°, helped a lot. Also look at the picture of the tool, it measures from the inside edge of the wheel arch, this is not the same as the outside edge!
Whatever you do, just be sure that you measure the same way each time.
Right, now the trick is, to add the amount that you want to lower the car compared to the factory ride height, to the value you enter in the IDS.
Example, if you want to lower the front by 15mm, to 371mm, and the front is actually at the factory height of 386mm, then enter 401mm into the IDS. Measure the other side and add the same amount. Maybe you don't want to lower the same amount front & rear? Then just add the amount you want to lower to the value.
After you've done all four corners, the car will go through a leveling cycle and adjust to the new height.
You then have to go and measure all four corners again.
Now here the car is thinking that it's actually at the standard factory ride height. If all's gone well, your measurements should equal factory ride height minus the lowered amount.
Once again you have to enter values into the IDS, by adding the amount you want to lower the car. Continuing the example from above, you should now be measuring 371mm, add 15mm to it & enter 386mm. The factory value!
If all goes well....
You should get a happy message!
When I first did this I dropped the front by 20mm and the rear by 10mm.
After a few days I realised that it was too low at the front, so I re-did it with a 15mm drop and it's much better now.
After a few days I realised that it was too low at the front, so I re-did it with a 15mm drop and it's much better now.
Still got room for the further 15mm drop on the Autobahn.
Sooo...that's that. I seriously doubt that a Jaguar Dealer would do this for you, best bet would be an independant workshop...
Last edited by Cambo; 06-21-2012 at 07:43 AM. Reason: Typo
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#2
06-19-2012, 04:47 PM
Veteran Member
Ha, so now we know the USP of the air suspension ! No need to fiddle about with special springs and tools, just plug in your lap-top and away you go !!
Personally, I think it could be even better if the 15mm auto-height reduction could be made to work at (say) over 40 mph, so the car is higher when we are around town and going over speed humps and rough carparks. Don't forget that lowering means less available suspension movement for normal driving.
Personally, I think it could be even better if the 15mm auto-height reduction could be made to work at (say) over 40 mph, so the car is higher when we are around town and going over speed humps and rough carparks. Don't forget that lowering means less available suspension movement for normal driving.
#3
06-19-2012, 07:12 PM
Thanks for tutorial! From casual post you have indicated and demonstrate that you have an up working IDS/SSD. I have looked on line but I'm still not certain of what to purchase.
Would you be will to post the list of requirements with a few pictures for those of that are a bit confused/unsure. Yeah that's me. LOL
I can see a lot of benefit from having that tooling
Would you be will to post the list of requirements with a few pictures for those of that are a bit confused/unsure. Yeah that's me. LOL
I can see a lot of benefit from having that tooling
#4
06-20-2012, 08:42 PM
Senior Member
#7
06-24-2012, 01:07 PM
@ ooootis & Sarc & anyone else wanting an IDS/SDD
There is a separate thread going on the subject https://www.jaguarforums.com/forum/g...an-tool-66558/
I'm pretty sure that will develop to answer all questions of what & where to buy
Arden has a piggy-back module system, that lowers the car when you select Sport Mode, I've emailed them for more information, to understand exact what one gets for €1500, I would hope that it overrides the 15mm drop at 160kmh and would be programmable for ride height. Let's see.
Thanks! TBH it's kind of hard to say. Summer is here so the road surfaces have turned to sh#t due to thermal expansion, I couldn't honestly say if the ride is firmer/rougher than before. It might be, but I don't have much of a reference. I mostly drive my X-Type which has lowered/stiffer springs, and rides very...sporty...
It doesn't ride like a Rolls Royce, but then again it's an XJR not a Super V8, I think the Comfort suspension of the Super makes a big difference over the Sport setup.
There is a separate thread going on the subject https://www.jaguarforums.com/forum/g...an-tool-66558/
I'm pretty sure that will develop to answer all questions of what & where to buy
Originally Posted by Fraser
Personally, I think it could be even better if the 15mm auto-height reduction could be made to work at (say) over 40 mph, so the car is higher when we are around town and going over speed humps and rough carparks. Don't forget that lowering means less available suspension movement for normal driving.
Originally Posted by Josh_77073
I'm impressed, you lowered it just were it looks good. does the car still ride the same?
It doesn't ride like a Rolls Royce, but then again it's an XJR not a Super V8, I think the Comfort suspension of the Super makes a big difference over the Sport setup.
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#9
06-24-2012, 08:06 PM
So, I played around with this Saturday morning, and recalibrated the ride height sensors through IDS/SDD. I lowered it by 15mm all around, but will probably raise the rear a bit, even though it's technically "level" as it sits now. I haven't noticed much difference in driveability, outside of noticeably less body roll. I don't know if I'll keep it like this, though.
#13
06-25-2012, 11:51 AM
Veteran Member
#14
06-25-2012, 01:43 PM
Veteran Member
So, I played around with this Saturday morning, and recalibrated the ride height sensors through IDS/SDD. I lowered it by 15mm all around, but will probably raise the rear a bit, even though it's technically "level" as it sits now. I haven't noticed much difference in driveability, outside of noticeably less body roll. I don't know if I'll keep it like this, though.
When I drove it like that, the steering wheel would shake when I hit a bump. That's gone after it has been restored to its original function.
#15
06-25-2012, 01:52 PM
Veteran Member
You know this brings up an interesting idea....
I'm sure those sensors produce some sort of electronic output. Most likely variable resistance (or voltage) depending on the sensor.
If we could electronically manipulate that output to mimic an overheight conditon, you could basically create an electronic ride height setup. Plus the ability to turn it on / off on demand.
Food for thought.
Whether u lie to the computer, shim the sensor or change its output electronically doesn't really matter all that much. All you are doing is forcing the computer to decrease the pressure in the bags and in turn lower the vehicle.
Take care,
George
I'm sure those sensors produce some sort of electronic output. Most likely variable resistance (or voltage) depending on the sensor.
If we could electronically manipulate that output to mimic an overheight conditon, you could basically create an electronic ride height setup. Plus the ability to turn it on / off on demand.
Food for thought.
Whether u lie to the computer, shim the sensor or change its output electronically doesn't really matter all that much. All you are doing is forcing the computer to decrease the pressure in the bags and in turn lower the vehicle.
Take care,
George
#16
06-25-2012, 02:02 PM
#17
06-25-2012, 02:07 PM
Veteran Member
Trust me, as the owner of an Arden car done at the arden factory, I know all too well how exaggerated Arden's prices are....
I wonder how much interest there would be in a project like this. Also the arden module uses the "sport" mode switch as the trigger. I think i'd prefer independent control.
Thoughts?
Take care,
George
#18
06-26-2012, 09:00 AM
I got an email back from Arden, not really much clearer...
Originally Posted by Cambo
Hi, can you give me some more information about your Sport Suspension Module for the X350 XJ? How much does it lower the car by? Does it override the the automatic lowering at 160kmh? Could you send me some more information on how it works? Thanks.
Originally Posted by Arden
thank you for your inquiry and the interest in our products.
If you install our Sport Suspension Module in your car it overrides the automatic lowering. If you push the “Sport” button, the lowering will be about 30 mm for a more sportive drive. This is possible by standing and also at a speed of 70 km/h till terminal velocity.
If you have further questions do not hesitate to contact me.
If you install our Sport Suspension Module in your car it overrides the automatic lowering. If you push the “Sport” button, the lowering will be about 30 mm for a more sportive drive. This is possible by standing and also at a speed of 70 km/h till terminal velocity.
If you have further questions do not hesitate to contact me.
#20
06-26-2012, 12:32 PM
I've got a copy of the 2004/2005 Model Year Technical Guide, which states;
- All models came with CATS
- 3.5L Sport, 3.5L Sport Premium and 4.2L XJR with C31A Sport Suspension
- The LWB models only came with Standard (comfort?) suspension, Sport was not an option.
- Sport was an option on the SWB cars.
I wonder if you got one of the early SWB Super V8's, it might have Sport suspension as an option? Hmmm...
- All models came with CATS
- 3.5L Sport, 3.5L Sport Premium and 4.2L XJR with C31A Sport Suspension
- The LWB models only came with Standard (comfort?) suspension, Sport was not an option.
- Sport was an option on the SWB cars.
I wonder if you got one of the early SWB Super V8's, it might have Sport suspension as an option? Hmmm...