The driver's front air bladder on my 2004 Jaguar XJR has sprung an ostentatiously noisy air leak, and after discussion with the missus we've decided that it's only a matter of time before the other springs fail (not to mention the compressor, the dryer, the suspension system ECU, blah, blah, blah). Time for a coil spring conversion!

There appears to be an entire industry that has sprung (ha ha) up in the past decade dedicated to air suspension retrofits. There are lots of also-ran vendors, but the two names that seem to keep popping up with consistent positive reviews are Arnott and Strutmasters.

Arnott's conversion kit (part number C-2290) is designed to fit all X350 chassis Jaguars, while Strutmasters (part number JA14RM) appears to have a purpose-built model specifically for the XJR. The Strutmasters kit includes an electronic module to silence warnings about the (now decapitated) air suspension failure, but I've seen posts in this forum that Arnott includes instructions on how to do this for 2004 model years Jags.

Other than this, the difference seems to come down to price, and (I would assume) ride quality. The only place I've found Strutmasters is straight from the factory, but the C-2290 Arnott kit can be had from multiple dealers and runs about $350 less. So... does anyone have any strong opinions one way or the other about Strutmasters vs. Arnott?

Thanks.

 

scooter, search for a 'suspension superthread' that I started like last year; I put all the options available and some opinions/feedback from people.


None of the manufacturers were willing to share with me their spring rates etc, but for such a small market with only a few competitors, not surprising.

 

I have no doubt that the coil conversions sprung from the fact that the early struts were over $2k each in the early years. So, imagine facing an $8k+ estimate for 4 struts!! The coils were a cost effective alternative to get you out of a financial bind.

Currently Arnott has air struts down to $400 each...which changes the landscape entirely. Cost is no longer a large reason to change to coils. The main argument for coils is now that it reduces mx over the long run. But, we have owned our car since new, ten years ago, and only recently had a single strut fail. Personally, I can live with that failure rate...and prefer to keep the air suspension. Remember, you lose the auto leveling function when you switch to coils.

To get a soft ride with coils on an empty car, you will face occasional suspension bottoming when the car is loaded. With air, the car adjusts so the ride and level stay the same, from one pax to 5 with luggage. Alternatively, if you choose a stiffer spring to support a fully loaded car , then you get a stiff ride when you're driving alone.

So...whichever floats your boat. Each has an advantage...and disadvantage!

 

For anyone reading this thread wondering what rosskuhns is referring to, here is the thread:

Suspension Options Super Thread! - Jaguar Forums - Jaguar Enthusiasts Forum

My 2004 XJR is mostly a weekend driver only (I work from home) and rarely has more than a driver and passenger and perhaps groceries in the boot. As for the ride, I came to the XJR from a three-year lease in a BMW 335i, so a stiffer ride wouldn't be an issue for me. The missus would prefer an even pillowy-er ride than what we have now, OTOH. At least one of us will get what they want.

The rosskuhns super thread is making this a difficult choice between Arnott and Strutmasters. On the one hand, some owners have reported issues with Arnott; on the other hand, they offer a lifetime warranty. On the third hand, Strutmasters doesn't have as many installs, but then again, they also don't appear to have as many issues reported. Arnott is less expensive, but Strutmasters has an XJR-specific model (I still can't find any information that spells out exactly what the difference is... stiffer ride than for the XJ8?).

Decisions, decisions.

 

Hi scooter,

Iam in same situation as you are few months back. I'm from Manila Philippines that's the reason I decided to convert my car to springs arnott c2290. Jaguar parts here are only available in jaguar dealer. I'll tell you the difference of the ride is almost night and day. In my opinion air is still better. Now my 2004 xj8 rides like a Camry as per my buddy..

 

Hm. Well, I guess that this just reinforces the fact that life is compromise. In my case, the compromise would seem to be some of the ride smoothness for peace of mind.

From my viewpoint, I still think I would rather have peace of mind vs. pouring more and more money into just one subsystem of an 11-year-old car (even one as great as the XJR).

Thanks for the feedback, mbclubph!

 

IMHO, I'd go with arnott. They have been the most helpful with me, answered my questions on install when I had an issue, and seem to really back up their warranty.
I was always a bit bothered on one strut master install where they forgot to machine one of the shock mounts or something. Sounds like they just have a big stock of shocks/springs and make each kit as ordered.

 

I guess your heading in the right path. I myself also considered the age of the vehicle. It's true that nowadays you can get arnott air shocks at a very reasonable price even the compressor but the problem doesn't end there. We're talking about many parts to make the air suspension work properly so converting to coils is the most practical solution and will keep you worry free for million miles to come.

Ride quality is ok but not comparable to air suspension but reliability wise it's way way better. In my opinion

 

I bought the Strutmasters. The ride is firm, but good. Now that the ride height is settled I'm happy with the look too. I don't think you can go wrong with either kit. I use my car for long trips and after an air suspension failure on a long trip I didn't want to chance it again.

 

2004 Jaguar XJR with new Arnott C-2290 steel coil springs installed

All done! The Arnott steel coil spring retrofit is complete on my 2004 Jaguar XJR. I just finished a 30-minute test drive that took kitty on freeways and surface streets at a variety of speeds, curves and road conditions to get a sense of the new vehicle dynamics. So far, the verdict is that it's slightly more transmissive of bumps in the road (which was to be expected), but it's definitely not a harsh ride by any means. The car rides roughly an inch higher than it did before, but as you can see from this profile shot it's not an objectionable difference.

There is one huge difference, though: being able to drive down the road with peace of mind, knowing that I will never be stranded by an air suspension issue ever again.

 

It looks stock height to me. Was your air suspension lowered or always riding low?

 

I bought a 2006 VP with low miles and soon the 2 front air struts were out. After reading much about what to expect in the future and much great input from this forum, I tried the Strutmasters conversion. Parts were about $1300 delivered. The shocks used were Bilstein.

Ever since the conversion parts were swapped I have been hoping for a miracle. The ride is harsh when it comes to negotiating cracks and sharp bumps in the road. My Audi A6 handles bumps better than the VP. I have checked out the whole suspension. The best explanation for the hard ride I can find is that my car has the Chrome 19" rims with low profile tires. I am thinking that if I had "real tires" the converted car would be better.

One thing I can say is the car never rides low anymore.

 

Mine was overly stiff for the first 1k miles. It's great now. I've had them installed for about 5k miles now. I also have 18"s though too.

 

You will need that extra inch when you put the family in the car...as it will no longer level itself.

 

I installed the Arnott conversion kit last night. Feels like OEM, but better. And the ride will only improve as the springs settle in a bit.

 

I'm wondering if I want to install one of these conversion kits. I have no faulty air shocks as far as I can tell but I honestly don't like the ride. The car does not feel safe. When compared to other cars I've owned, it feels floaty, like its riding on marshmallows it does not inspire confidence at all.

Perhaps a conventional shock/spring setup will cure this.

The question I have is: could the ride feel like described above due to some suspension component failure?

Thanks in advance.

 

Component failure? Probably not. My understanding it that the CATS system will settle down at highway speed, so the handling should be better at speed. You might be reacting to the cushy low speed ride. I would not have put in the Arnott coil conversion if my CATS system had been reliable and error free. However, when I decided to do the coil conversion I went with the Arnott system as they were very responsive answering questions, and they had a 'sport' version with higher K rate springs available. I was a bit concerned that there was only one part number for both regular XJ8 and XJ8L, but was very pleased with the conversion. The after conversion ride height is proper, and the springs stiff enough so I don't miss the CATS system at all. Even with four adults and typical luggage in the truck the ride height appeared (by eye) to be normal and handling was fine.
I think I might have picked up a little more road noise, but I also did new tires at the same time. The Pirellis I put on are a much higher grade tire and might just transmit more road noise. I am very happy I got rid of the anxiety of wondering just what was going to go wrong next with the air suspension system.

Summary:
1. I personally would not convert a properly working and reliable CATS system to coils. CATS is a pretty cool tech system.
2. If you do convert, my experience with the Arnott SPORT version was great.

I don't have any experience with other conversion kits or manufacturers to know how they stack up.

 

Thank you for your opinion. All very valid.

 

Is your Arnott experience positive enough to work with an Arnott marketing rep to create a short 'User Story' or 'Success Story' ... ?

If yes, reply to this message or send a message to greg at gf7446@comcast.net ...

The 'User Story' would require 15-20 minutes on the phone and then approval of the finished written piece, which would post on the Arnott website ...

Arnott gear and a future discount on purchased product would be an incentive we can offer!

Thanks ...

greg

 

I just wanted to chime in. I installed the Arnott coilover kit on a 2004 XJ8. It is a huge downgrade from stock. I wish I had never done it. The car is fine on very smooth pavement but it is way too bumpy over minor cracks in the pavement. I should have just replaced the one failed air shock for $400 and been happy until the next one failed.