I have a 2004 XJ8. I'd like to attach a trailer hitch, but the official Jaguar way involves a complicated interface to compensate for suspension lowering, and costs over $1000 just for the parts.

If I can either turn off suspension lowering, or if I can stay below the speed at which it begins, I can look for a cheaper solution with no lowering.

 

This suspension lowering thing is probably about the most stupid feature on these cars, as the car only lowers over 100 mph. So how many drivers outside Germany are driving over 100 mph every week ? Almost none, I'd say.

Even German autobahns have restrictions now, and a recommended limit of 130 kph where no fixed limit.

 

Xeno,

I agree with Fraser that you don't need to worry about the speed lowering feature. And just to be precise, according to the 2004 model year Jaguar Service Training Course / New Model Introduction manual, the air suspension will enter speed lowering mode when the vehicle exceeds 105 mph, at which time the suspension will lower 15 mm. When the speed is reduced to below 80 mph, the vehicle will automatically default to the standard ride height again. (page 7-22 dated April 2003).

Cheers,

Don

 

Are you sure it's that fast? I've seen mine come back up after riding on the highway and having not gone over 80 mph.

 

It's 160km/h or 100mph from what I read in the tech guide, and then it raises again when you drop below 140km/h.

Have a look for my thread "how to lower your X350" there was lots of info in there.

Don't forget that the suspension in these cars reacts to rough road surfaces or big changes in approach angle, for example the driveway into my house is steep and the suspension raises itself as I drive down, when I park the car in the garage its sitting an inch or so higher than normal, and once level in the garage it lowers itself again.

It's actually quite a clever system, just a pity we have no manual control over it like other air suspended vehicles...

 

I wonder if the system was programmed differently for some markets? As I mentioned, the North America dealer training manual for the 2004 XJ new model introduction clearly states the suspension lowers at 105 mph, then raises again once the speed drops below 80mph.

Cheers,

Don

 

I know when I get off the highway and am at the end of the off ramp, I can feel and see the front of the car raise up on me. the car is usually parked in a level garage overnight and during most days. When the car lowers at 105 mph, does it do so at all 4 corners?

 

Well, the original Technical Guide (2004) says 160 kph (100mph) and above for more than 10 seconds and it lowers 15mm; 140 kph (88mph) for more than 5 seconds and it raises to normal.

However the 2012 'Chassis Systems' document says above 170kph (105mph) down (no time given); below 130kph (80 mph), if lowered, then raise (again no time).

It lowers all four wheels. Somewhere I saw a post that alleged that when it lowered it lowered the front first, and when it raised it raised the rear first, to avoid the dip beams dazzling oncoming traffic. I've no idea where that came from, nor if it's true (it's not in the 2004 or 2012 documents).

 

Thanks for clearing that up! :-)

I don't recall reading about the order of lowering, but the '04 New Model Year Introduction Dealer Service Training manual does state that when the car is started, the suspension raises at the rear first before raising at the front "because it was found that customers did not like the sensation of the car raising at the front first," (paraphrased from memory). So it would make sense that the system would operate in the reverse order when lowering.

Cheers,

Don

 

Ah ... chrrs Don; it may well have been that.

I couldn't agree more with Fraser that, with the current speed settings, it's a dumb feature. I rather suspect it might have been put in by a designer ... 'just because (s)he could'.

It would be far better if it lowered somewhere in the 65-75mph range, and lifted at 10 or 15 mph lower; although whether there would be any real aerodynamic advantage at those speeds I don't know. The down side at those speeds is that it would be going up and down more frequently and that would be putting more wear on the compressor piston ring (an 'Up' side of 'BP' Andy of course).

 

Hi,
the speed setting is well chosen.. from a german pointof view.
At speeds higher than 200km/h you start to feel forces you never experience in some "free countries". Force goes by the square of speed, so at 250km/h forces are nearly 3 times stronger than at 150km/.
BMW, Audi or Mercedes are setup "hard" to be driven at high speed. The jag perfectly transforms between a comfortable slow and a secure highspeed ride.
That's why I love my car

 

If you search on the Jaguar Lover's forum they have the brochure for the 2005 XJ8. If I remember correctly the stats give a maximum tow weight of 4100 lbs and a maximum tongue weight of 160 lbs. Plus the Jaguar hitch is weird looking and might not be legal in the USA.

The general rule is that tongue weight should be 10-15 percent of the weight of the tow. This is to avoid excessive trailer sway. Jaguar's 160 lbs would only be enough for a 1600-2000 lb trailer.

I would not use my xj8 as a tow vehicle. I tow with an F-150.

My $.02

Tom