So, I'm at that familiar crossroads where I need to decide whether to pursue fixing my air suspension or do the coilover conversion. My Jag has 173K on the clock and is going to require (at a minimum) a rear air strut. I'm typically a purist, so I get the people that want to keep the air suspension at all costs, but I really haven't found anybody that seems to regret converting to coilovers (save for a few people that bought the $500 Chinesium eBay specials).

At the moment, I'm leaning towards get one of the Arnott conversion kits (although I'm currently struck with choice paralysis) and I'm interested in any feedback people would offer good, bad, or otherwise.

 

I went for the Arnotts on exactly the same car with about half the mileage, and am very happy. The ride seems a bit firmer at speed ( i have never driven an 'R' for comparison ) and not as prone to porpoising over large bumps (like speed bumps, or traffic calmers) at very low speeds. IMHO

 

i’ll be installing stype v6 coilovers soon. i’ll let you know how it rides

 

Do you happen to remember which part number you got? They seem to have two different models for the X350: One is part number C-2745 and the other is C-3270.

In my searching, I've seen some allusions to the possibility of installing S-type coilovers on an XJ8. However, I've yet to find someone who has actually done it, so I'll be curious to hear how it turns out. Pardon my ignorance, but is the cost the main benefit of using S-types over the conversion kits made specifically for our cars? Would you have a perpetual air suspension fault message?

 

see here: https://www.jaguarforums.com/forum/x...n-79499/page5/

As I understand the S-type springs keep the vehicle height closest to original. The problem is the mount bolts are different requiring some drilling.

What I want to know is if one can get an off brand kit and swap out just the springs - the best of both worlds.

I have some off brand on mine right now - drives just fine, but the rear is way too high. For me I could pick up some S-type springs and swap them out as the rest is already purchased.

 

Sorry, Electechbw, an Indie in Panama City Beach, FL ordered the Arnotts directly from them, and I don't have any paperwork with a part # on it.

 

"fixing my air suspension or do the coilover conversion. My Jag has 173K on the clock and is going to require (at a minimum) a rear air strut... I'm typically a purist,

The question I've not seen asked, never mind answered:
So how many times has the air suspension been changed for 173k?
OR if newly replaced, how many k do you intend to do?

(hint: I'm a purist. But then I can afford to be at 90k, or maybe I'm on borrowed time already...)

I don't believe it's directly related to km. More like: some leak more than others, but excessive leaking within reason is only gonna wear out the compressor?

If the bladders bugger, is that a time constraint on rubber stuff?
I try to keep my bladders out of the sun </s> Anyway, they are not subject to heat like coolant rubbers. And they aren't subject to too much variation in normal driving (apart from the car lowering at motorway speeds). ?
I have said that mine leaked when parked for days. Sometimes. Currently they don't leak at all - self fixing, lucky, I dunno.

 

Electechbw

I replaced the CATS struts on ,my 2005 XJR with a set of S Type v6 struts over a year ago and am very happy with results Only complaint is I lost the auto leveling on my headlights. Your car may not have auto leveling so it may not be an issue for you.

My right front CATS strut would bleed off in the winter. I do have the rear struts off my car available and will sell them cheap. My car had a 117,000 miles when I took them off.

Wooford Jag

 

I'd just point out this post:
X350 Air Suspension Problem - Diagnosis - Jaguar Forums - Jaguar Enthusiasts Forum
#20 (DonB)

 

Those are good questions and really hit the heart of the matter. I bought the car from a fellow forum member and Jag enthusiast in 2017 ago with 153K miles. Both fronts have been replaced somewhere between 2014 and 2017 and rears are likely original to the car. The second question is trickier. I have no intention of getting rid of the car and I've been very lucky so far, but I also have to be recognize that this is a 16 year old car with 173K miles.

Thanks for the info. How did you turn off your Air Suspension Fault message? If I decide to stick with airs, but I'll consider your offer. My mother-in-law lives in Lexington, so my wife actually might give me too much grief for driving 3 hours to buy car parts.

 

Replaced mine with the cheap imports on E bay several years ago. Work fine, ride height a little high. Ordered them the day I bought the car. Wasn't going to deal with problems and expense of air suspension. Head lights seem odd when car started in garage. Don't know if headlights are auto adjust 05 VDP. As I recall the rear upper studs are not symetrical and must be indexed correctly, fought them until I finally figured that out. Remove relay and a 10 amp fuse, cant remember which one but an earlier post explains it.

 

From what I can gather (following this subject for a few years): (and Maintenance Aside!):
-No-one is unhappy with coil-over conversions.
-It is "nearly" the same as CATS, though I don't recall anyone saying it is "better" (ride-wise)

At one stage I wandered into a Mercedes forum, and some of their models have the same air system and same problems. The Suzuki Baleno does not. I could have bought a Mercedes, or a Baleno, apart from the shape and promptly getting thrown out of this forum.

I Love my X358, even though I KNOW the CATS was just a marketing ploy really. Perfect really (list your own problems, on second thoughts don't)

And have some sympathy for X351 owners. They took HALF of the air suspension out, presumably halving the problems!

 

If anybody is interested, I contacted Arnott about the effective difference between the two conversion options they offer for the X350. Here was their response:

 

Oh, thanks for that! I was just seeing the two kits, and not seeing any difference other than the 3270 stated it used Eibach springs. Without saying what was different about those springs, that's kind of a "so what?" piece of info.

 

Hello Mr. Electechbw -
I have a 05 super V8 - replaced air shocks at about 140K with the kit from Strutmasters. $999 for the kit, 800 for the work at the shop I use. Kit comes with instructions to reroute electronics so that car doesn't give suspension fault.

Most difficult thing in replacement for my shop, and for many others, is getting the back seat out to access the electronics panel that sits just behind the rear seats. My shop showed this to me and it's an impressive array of electronic boards. No wonder our cars go wonky sometimes!.

I'm happy with the conversion and especially the peace of mind that comes with it. I knew there would be lots else to do on my car so I went with the simplest solution. I must say I like the ride but when the ECATS is working there is nothing like it IMO (mine worked intermittently for a short time).

HOWEVER - Over the past few months I've also had to replace in normal maintenance the front and rear suspension parts - meaning the upper and lower front control arms and wishbones, the front tie rods and sway bars, rear control arms and toe links, and one other rear suspension part. So after 2 years and 20K miles of limping along with wonky bushings in those crucial handling parts, my car continues to inch closer to its true superior ride and handling characteristics.

Also when I talked with my shop regarding my slight remorse in not using the sporty Arnott's, he replied that my car was meant and built for a comfort ride and the Arnott sports would try to make the car something it's not. I was satisfied with that answer. BTW I push my car fairly hard and love to engage the SC, I can say that the ride and handling is adequate - direction changes must be done carefully as my car now really responds to steering input with all the new suspension work.

It is in the shop right now - there seems always a surprise - this time the brake lines were so old that they needed to be replaced at a cost of 200$ EACH. They are also hard to source and this time I had to overnight them through our local Jag dealer to my shop. SURPRISE!

Finally - just in case you want the info - all of the suspension parts I mentioned above are indeed shared parts with the S-Type and the S-type parts are much less expensive. I ordered all of them through FCP Euro, and these are OEM Lemforder so they are real quality.

Despite the cost of doing the cars rear end and the surprise brake lines, I can't wait to get the car back.

If you want the exact parts numbers for the suspension stuff I can send them. FCP sells the rear arms as a kit for $500 - total order for rear was just over $800, for the front was about the same. They often run 10% discounts. I'm really happy I did not cheap out these parts in any way - enjoyment plus safety.

Obviously I plan on keeping the car 200K is the goal driving about 10K/year that's another 5 years or so.

This is my experience.

Mike D.

 

I have been through this with my 2006 VDP that I purchased in November, 2019 with 24K miles.

The Jaguar technical literature (which I have) claims that the air suspension system not only adjusts for ride height, but also for forward and backward leaning of the car (i.e., under heavy braking or accelerating), and side-to-side sway (i.e., cornering or even changing lanes). If I understand things correctly, it keeps the body of the car from moving so much by siffening the springs when certain conditions arise (i.e., hard accelerating or braking, sudden turn of the steering wheel). Under normal conditions the springs are softer.

The front air springs on my car went bad so I had a set of Arnotts installed. In subsequent discussions with Arnott they explained that all their springs do is adjust for ride height. They don't make any of the other adjustments that the factory springs make. I then realized that what I had on my car was front springs that were only adjusting for ride height and rear (still the factory) springs that were adjusting for the various other conditions. That bugged me.

In short order it needed rear springs. This time, I found a company in Florida, Rebuild Master Tech, that rebuilds the factory originals (typically, you have to send them your old ones). They do this for $250 per spring, and that includes shipping.

The Arnott springs cost $500 each. I realized that I could have all four of my original springs rebuilt (I had saved the original factory fronts) for the price of two new Arnotts for the rear. I didn't like the idea that the Arnotts adjust only for ride height, so I decided to have all four originals rebuilt. I really do want the car to ride and handle like Jaguar intended. The only added cost would be the labor to have the front ones replaced again. I subsequently sold the used Arnotts on ebay for $300 total (I was glad to get anything for them).

RMT claims they do something in the rebuild process to correct the flaw in the Jaguar design that keeps them from leaking as they age. I couldn't get them to tell me just what it is they do (I didn't blame them, but I did ask to see if they would tell me).

I have found the car will lose an inch and a quarter in height overnight, but they come right back up in seconds when the car is started the next morning. I think there is something in the Jaguar literature that the system will change the height after the car has sat for a while. I guess that is what is going on. I have no problems with the RMTs, as far as I can tell. Though maybe they are leaking and that is what is causing the car to lose height overnight. But for now I am fine with the way it is. And the car rides and handles as Jaguar intended.

 

That's not my understanding at all. What you're describing is active suspension, which this is not. From the X350 air suspension manual linked in the "Air Suspension and ECATS" sticky thread: "The Xj air suspension system is not an active suspension system but a system in which the air bladders replace the conventional coil springs." So the air system will level the car for load, but not for dynamics. The ECATS is dynamic, but it's shock valving, not springs; it doesn't stiffen the springs, it changes the damping in the shocks.

 

Electechbw,

I unplugged the control module behind the rear seat and did a hard rest by putting the positive and negative battery cables together for about 15 seconds, Lights are out.

Wooford XJR

 

By chance could you snap a pic of your shock towers, just so I can get a rough guide on where to drill?

regards

 

Xalty,

You basically cannot see any difference. The shoulder nuts that hold the struts in the body cover the modification. Each of he mounting holes had to have about 1/4 inch of material towards the center removed for the mount to fit. The S type struts lowered the car 3/4 to 1 inch verses stock height.

Wooford XJR