8-year-old thread... but I'll chime in. My experience was that my air system was hopeless, and I've not looked back since putting the Arnott coilovers on the cars. I have no complaints, but I can't compare it to a working air system because I've never been in one that was working. In my situation, the expense of what my car needed simply made no economic sense, as it was a significant fraction of what I paid for the car, a cost I couldn't even begin to hope to recoup.

 

Hi everyone,

Because the X350 & X358 XJs are aluminium bodied and can in theory last indefinitely (and soon will start going up in value - or at least not depreciating) the air suspension systems are going to be increasingly replaced with coil-over suspension.

I have had my XJ for a very long time and wish to keep it, but I am not a fast driver and have never needed the suspension system to keep the car absolutely level when cornering at very high speeds. Also, at under 50mph the XJ suspension is relatively poor at absorbing shocks and reducing driver fatigue; this is the well known weak loint of this Jaguar model - something I have never been happy with as I always drive at 50 or less when not on a mororway. Therefore I have a question about the Arnott coil-over suspension kits . . .

Can anyone tell me if the Arnott kit improves shock absopption at 50 mph or less? In other words does the Arnott kit remove the weak point of the XJ and provide comfort at normal driving speeds - or does it perpetuate the problem, or even make it worse and more bumpy?

Also, I notice that then Arnott website shows two versions of their kit: The C-2745 and the now discontinued C-3270. So if anyone does have an answer then it would be great if they knew which Arnott kit their answer relates to.

Kind regards

 

This implies a fundamental misunderstanding of the suspension system, along with an improper expectation. It is NOT intended to level the car during maneuvering, as it is NOT an active suspension system. It levels the car by static load; you put stuff in the trunk, the back of the car stays level. You put my grandmother in the front passenger seat, the car doesn't lean to that side all day. The air system makes NO EFFORT at all to respond to cornering and braking loads, and indeed is nowhere near responsive enough to do so. Just think about a car that has sagged by being heavily loaded... it takes a couple of minutes to come level. That's the response time of the leveling system, so it certainly has no ability to fight maneuvering loads. That's not its purpose.

The ONLY response the suspension has to maneuvering is the CATS system, which is damper valving, not ride height. The CATS system has nothing to do with the air system; it simply firms the dampers if the car is being thrashed a bit.

First I've heard of this "well-known" problem, after over 4 years of ownership and membership on this forum. If you're saying you're experiencing a harsh ride, that's a symptom of a poorly performing, or simply worn, air system. Dampers do wear out and lose their effectiveness. The ride quality in my car was completely unacceptable after a few weeks of ownership. Nothing that showed on my test drive, but as I used the car more and more, I experienced things that made me think, "This just isn't right," along with "Air Suspension Fault" messages getting more and more frequent, and having to wait for the car to rise in the mornings on first start.

My car was completely transformed when I put the Arnott coilovers on it. It initially sat pretty high after the change, but I'd seen posts that made me expect this, as it does settle to a normal ride height fairly quickly. The ride quality is the best of any car I've ever owned, and being 67 years old, that's a significant number.

As for the two part numbers, one is designed to replace what Jaguar calls the "comfort" system, and the other is designed to replace what Jaguar calls the "sport" system. The sport system did have a stiffer ride, as the OEM air struts had smaller air bags, the air equivalent of having stiffer springs. The coilover Arnott still sells is the comfort version.

 

Listen to woofshee as I also fought the air suspension for some time before going to coils. His description of how the air suspension and the CATS work is correct. There is no "well known weak point"? This is an urban legend at best. What is a well known weak point is what your experiencing and that's the entire air suspension setup.

Please do some searches and reading as you only have 1 post so you don't understand the level of problems the air suspension has and is causing?
We have many threads with both problems and solutions so start by getting educated on the system first.

Can you DIY anything? That is the key to owning a used Jaguar. That and this forum with it's massive depth of knowledge and experience will keep your car going!
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[QUOTE=wfooshee;2832128]This implies a fundamental misunderstanding of the suspension system, along with an improper expectation. It is NOT intended to level the car during maneuvering, as it is NOT an active suspension system. It levels the car by static load; you put stuff in the trunk, the back of the car stays level. You put my grandmother in the front passenger seat, the car doesn't lean to that side all day. The air system makes NO EFFORT at all to respond to cornering and braking loads, and indeed is nowhere near responsive enough to do so. Just think about a car that has sagged by being heavily loaded... it takes a couple of minutes to come level. That's the response time of the leveling system, so it certainly has no ability to fight maneuvering loads. That's not its purpose.

The ONLY response the suspension has to maneuvering is the CATS system, which is damper valving, not ride height. The CATS system has nothing to do with the air system; it simply firms the dampers if the car is being thrashed a bit.

OK I never knew that. On the odd times I have driven the car extremely fast around sharp bends it has remained remarkably level so maybe that is the CATS system you describe.


First I've heard of this "well-known" problem, after over 4 years of ownership and membership on this forum. If you're saying you're experiencing a harsh ride, that's a symptom of a poorly performing, or simply worn, air system. Dampers do wear out and lose their effectiveness. The ride quality in my car was completely unacceptable after a few weeks of ownership. Nothing that showed on my test drive, but as I used the car more and more, I experienced things that made me think, "This just isn't right," along with "Air Suspension Fault" messages getting more and more frequent, and having to wait for the car to rise in the mornings on first start.

My car is no longer maintained by the main dealer and I use a Jaguar Main Dealer 'Master Technician' who left Jaguar about the time the X351 was introduced to set up his own Jaguar specialist. He has often mentioned it, saying it is the problem with that and many other air suspension systems - and I have seen it mentioned many times. In fact Jeremy Clarkson once participated in in a range finding test of European luxury cars to see which got furthest on a full tank. He was driving the TDVi (which either won or was close) and during that TV episode he made a point of saying how good the XJ's ride comfort was at speeds over 50mph but how bad it was at below 50.
I bought the car at 1 year old with about 9,000 miles on the clock and was immediately unimpressed with the ride quality at below 50mph so I phoned Jaguar Cars Ltd head office to ask what my options were - got put through to a very knowlegeble gentleman who agreed that the bwlow 50 mph ride comfort was much better on previous XJs and explained that that was a drawback with air suspensions. He advised me (verbally) to choose the softest tyres possible - especially side walls - to fill them with nitrogen and to run at the minimum permissible pressure. I have got 235/55's on mine and that adivce proved good. Obviously, compared to an Audi or BMW the X350 will seem extremely comfortable at below 50, even with low profile tyres, so a person's perception of shock absorption quality will be effected by that in their last car. (My previous car to the XJ was a 1996 Mercedes E220 Coupe - for which I still have the original brochure and in it it emphasises superior ride quality, stating that the seat structure is tuned to the car's suspension.)

 

Thanks for the information about the Arnott coil-over kits.

My specialist said he thought Arnott coil-overs had some sort of adjustment on each shocker and that an adjustment can be made prior to fitting. Have you any information on that aspect?

 

Thank you for the info. I have not DIY'd car repairs since the 1970's when I spent Saturday mornings detaching parts from cars in scrap yards and then fitting them over the coming days. I prefer to use an experienced Jaguar mechanic for repairs because I am always busy and I don't have a ramp or a pit. Also the guy I use is more than happy to discuss every aspect of his work and proposed work, even though he was a full-on certified Jaguar 'Master Technician' before setting up on his own - he's a really great person like that, so me learning things from reading on-line posts and talking to him about it is just a plus.

 

My car is no longer maintained by the main dealer and I use a Jaguar Main Dealer 'Master Technician' who left Jaguar about the time the X351 was introduced to set up his own Jaguar specialist. He has often mentioned it, saying it is the problem with that and many other air suspension systems - and I have seen it mentioned many times. In fact Jeremy Clarkson once participated in in a range finding test of European luxury cars to see which got furthest on a full tank. He was driving the TDVi (which either won or was close) and during that TV episode he made a point of saying how good the XJ's ride comfort was at speeds over 50mph but how bad it was at below 50.
I bought the car at 1 year old with about 9,000 miles on the clock and was immediately unimpressed with the ride quality at below 50mph so I phoned Jaguar Cars Ltd head office to ask what my options were - got put through to a very knowlegeble gentleman who agreed that the bwlow 50 mph ride comfort was much better on previous XJs and explained that that was a drawback with air suspensions. He advised me (verbally) to choose the softest tyres possible - especially side walls - to fill them with nitrogen and to run at the minimum permissible pressure. I have got 235/55's on mine and that adivce proved good. Obviously, compared to an Audi or BMW the X350 will seem extremely comfortable at below 50, even with low profile tyres, so a person's perception of shock absorption quality will be effected by that in their last car. (My previous car to the XJ was a 1996 Mercedes E220 Coupe - for which I still have the original brochure and in it it emphasises superior ride quality, stating that the seat structure is tuned to the car's suspension.)

 

Well, first, filling street tires with nitrogen is a complete waste of money. Racing cars fill with nitrogen because of the extreme temperatures their tires reach, which is actually high enough to turn any water vapor in the tire to actual steam and significantly raise the tire pressure. This is not a factor on the street, not even a little bit. Your street tires vary in pressure more just by having a cold day versus a hot day. Nitrogen in a street tire offers NO advantage, and anybody claiming otherwise is spouting old wives' tales.

I won't argue with you about the under-50 harshness because I've never driven a working air suspension system, but while Jeremy Clarkson may have remarked about it, that's not Gospel as far as I'm concerned, and your mention of the harshness it the first I'd ever heard of it in my several years on the forum. I will say definitively (again) that my Arnott-suspended Jag is by far the most comfortably riding car I have ever owned.

 

OK let get started. I had a 2004 vdp several years ago. I loved the ride with the CAT system. I sold the car but that was my mistake. I recently, a couple of years, purchased a 2005 VDP and completely rebuilt it. From worn suspension parts to the shocks. It came with Strutmasters on the car so I did not experience the air suspension. I noticed that the shocks made all kinds of noise. So I replaced them with a generic Rock Auto brand. Big mistake, so this is what I would do now. If I had the factory air suspension, keep it until it either is unfixable or you can not stand it any longer. I have a independent Jaguar mechanic that explained all the VDP shocks for me. He told me that Arnott used to have great customer service and products but not so much any more. But that is his opinion. I want a adjustable soft ride. BC Racing Adjustable coil overs has been reviewed on this site. It sounds like you can adjust the ride height as well as the comfort of the ride. This maybe something to look into. The person on this site was very happy with his purchase. If not BC, I would go with Arnott system. At least you can get help with a name brand.