I've been eyeing the Strutmaster coilover conversion kit for my 2004 XJ8 for the last year or so, just haven't pulled the trigger yet. For anyone else in the market, their prices have come down for the kit by 300-400 dollars (they're 1000 now...last I checked they were about 1300-1400). I know there are other conversion kits out there, I just kept coming back to this one because of the components.

I chatted online with one of their reps and they do give a little price break for "return customers," too. The website is a bit confusing right now as he said they're in the process of dropping the prices online. The "F" model is for the XJ8, and the "R" model if for the XJR. The R model had a higher price at one point, but you click through it and it looks like it's the same price as the F model.

BTW I am not affiliated with the company at all, nor do I even own their kit. I was just surprised their kit was less expensive now, since it seems as if others I've looked at have gone up over the last few years. Just wanting to pass on the info for others interested.

 

Attached pics.

Now, be aware... Many posts say that the shocks are Bilsteins. This is due to the Strutmasters site pics with yellow shocks that are clearly Bilsteins. Problem is that Bilstein shocks from the S type R model which are Bilsteins..are not yellow. they are black for the rear and green for the front

What I just got from them are rather generic looking black shocks with red Eibach springs.

I'm going to install them tonight. Ill let you know my impressions in about a week or so. If i think there is room for improvement, I already have a plan:

Given that the kit was on sale for $999.00 and real sport Bilsteins shocks could be had for 400 bucks, im thinking of making a hybrid system that will be much higher quality than anything out there.

Part #s for 2004 S Type R with 4.2 supercharged:

Bilstein 24-067430 Monotube Shock Absorber, Front, 36mm

Bilstein 24-067720 Monotube Shock Absorber, Rear, 46mm

So i'd still use the upper mounts that came with the strutmaster kit, the eibach springs, and of course the warning light disabler. Price will still be a few bucks less than Arnott

 

Well that's a bit of a deal breaker. I thought the struts in the kit were higher quality. I'll be looking forward to your review. Unfortunately we won't really know the actual quality until they've been on the car long term.

I've considered S Type replacements, but don't know if I want to go the drilling route. You would think a company would make top plates to adapt the S Type suspension to the x350, then you could really build your own. Though then you run into spring issues, too. Sounds like the S Types sit too low in the rear for our car.

Do the Eibach springs have a part number on them? I'm wondering if you can buy them separate?

 

Eibach does not sell Springs for the S type. but the part number on my springs are: SMSP53. They still claim in their advertising that they use Eibach springs, no reason to doubt that...but nowhere do they claim to use Bilstein shocks..they just left pictures of what is clearly a Bilstein shock on the website. Its entirely possible that they have subcontracted out the shocks to Bilstein, but its also possible that the did the same with KYB..or worse..Gabriel. Im planning on a total suspension rebuild and going the aftermarket swaybar route in a few months anyway, but cold weather and failed airsprings necessitate that the strutmaster units go in right now. I want to be clear...I think that these are still the highest quality units available in a kit as it stands right now. Arnott makes their stuff in house (in china) and im not impressed.

I did a ton of research...Strutmasters has an excellent reputation with their air spring conversion products in the Mercedes community. No one seems to talk badly of their products.

Now, on the DIY front...I think you could easily buy a KYB strut mount kit and do what Strumasters clearly did...saw off or press out the existing bolts and weld on an adapter ring with the larger spacing on the bolt pattern. any welder or machine shop should be able to do that. Id be happy to take detailed pics and measurements for you of the SM tops if you like.

The consensus seems to be that the springs from the S type R are fine for our car...just wouldn't want to go lowered spring route. Again..im happy to take measurements if you want.

But don't forget..you still need a reliable way to cancel out the air suspension fault message.

I am more convinced then ever of the Bilstein S type R shocks being completely compatible. the weight of the 2 cars is with in 100 pounds and both have very similar weight distribution.

The hybrid route im contemplating would still be pretty cost effective and would definitely be the highest quality, lowest drama route. but hey..everyone else who went the SM route so far seems to be happy with the results. I'm just a Bilstein snob. maybe you can call them back and try to get a direct answer on the shock source company.

 

I couldn't find the model number on any Eibach springs online. The discription is very clear that the springs are Eibachs...perhaps they do not sell them separately to the general public. I sent Strutmasters an email regarding the strut brand, so we'll see what they say. When you zoom up on the yellow strut picture on their website, it shows "Strutmaster" on it. But you said yours were black, so who knows. Their kits do have a limited lifetime warranty, so...

As far as the warning light goes, if you haven't, have a look at this thread.

https://www.jaguarforums.com/forum/x...-110745/page2/

From what I've read, as long as your x350 (only applies to 2004-2007) hasn't had a software update, you can unplug the ASM and it won't throw a fault. Also, there have been one or two members here who have yanked out all of the air equipment (ASM, struts, lines, compressor, tanks, etc) when they converted to coilovers. If I'm not mistaken they didn't have any major problems doing so.

I appreciate the offer to measure the top plates. I'm not sure if having a shop make one vs drilling holes would be easier. Ofcourse drilling is permanent, but you'd have more suspension options. I'm surprised the type R springs in the rear don't make the rear end look saggy. The member on here that swapped stock S Type springs had saggy/negative camber issues in the rear.

 

If a person is truly unwilling to maintain the air modules, I would make a couple of suggestions. Using the XF upper mount, and H&R progressive springs, with Bilstein S-Type monotube with CATS (green in color) would be the first selection. This would require disabling the compressor, and recalibrating the height sensors. (required for CATS) but would retain much of the functionality of the stability control. Many try to use the roll bar as the method to compensate for what the spring and shock should be actually doing in the arena of body roll. Just sayin'

 

So the XF upper strut mounts are a direct bolt in to the x350, requiring no modification? Then you would get the h and r springs for the S Type and they would seat well with the XF plate?

From what I understand, when utilizing the CATS on a strut like the type R they basically control the rebound and not the compression. Are there any other benefits of using a CATS system on a coilover setup? Reading around, it seems like it's kind of a wash for people on whether or not they'd replace a worn out CATS coilover setup with another CATS capable setup.

 

I've not personally tried this. But if I were to go to a spring option, that's the path I would pursue. Strutmasters do not provide progressive rate springs, nor do they provide CATS. To my knowledge, Bilstein is the only one who can make that happen. (CATS) The Bilstein B4's (both shocks for the XJ and the S-Type are basically the same) if I'm not mistaken, switches between roughly a 30/70 (comfort) to an 80/20 (stiff) profile, and uses parallel settings in both compression and rebound. (which means they both change, and is called 'damptronics') It's not a variable rate, but an on/off profile determined by 400Hz PWM to the solenoid inside the shock itself. By default it is stiff. (off)

 

Where did you get the idea to use an XF top plate? I just hadn't heard of that before...wondering what the benefits are?

As a side note, here's another thread where Jagzzz said the struts that came on his Strutmaster setup are Bilsteins (post #12).

https://www.jaguarforums.com/forum/x...arison-149875/

I wonder if they did change to a cheaper setup...that may explain part of the recent price drop.

 

Just received a response back from Strutmaster. Apparently Bilsteins or Sachs are what they use for the XJ coilovers.

 

Strutmaster does not, to my knowledge, use a CATS compatible shock in any of their conversions. You might verify before you purchase. Just because it says Bilstein, doesn't mean it's a "damptronic" one. (CATS compatible)

 

+1 on this comment

 

1) XF strut mount is conjecture. No one seems to have posted anything about this in a real life install.

2) CATS on coilovers has been verified with only one user...Sochi2014. He reports S type R with electronic shocks plugged in with the X350. Problem is you cant buy those units new anywhere. He went with used ones from japan.

3) The Strutmasters coilovers are the highest quality units you can buy. I'm happy with mine.

4) The aftermarket XF sway bars have been confirmed by several users...with all positive reviews.

5) CATS with air suspension was a failed experiment. it only lasted 5 years. Jaguar ditched it in 10'.

 

I think you'll find the XF strut mount has the same bolt spread as the XJ, and you can do an easy comparison to the S-type. There are plenty of pics. I think you'll find what I said to be accurate. The one thing you really don't want to do, is to hack away at the upper strut towers to fit a S-type strut mount.

Whatever you may feel about shocks, Bilstein B4's w/CATS (green in color) for the S-Type is available in the US market from numerous vendors.

While Strutmasters may sell coil-over kits, there are numerous options for those who are seeking other options like build your own, and to say that Strutmaster builds the highest quality you can buy is subjective.

While you may feel CATS is a "failed experiment" it certainly is part of the way the vehicle's safety systems, including skid control, body roll, ride quality and overall handling depends upon. Jaguar is not the only manufacturer who use air modules, and understanding CATS is not air suspension per se, but shock control. CATS both predates, and continues after air suspension modules in the Jaguar lineup.

If you want to make changes to your XJ, have at it, but you might take a second and consider there are other options besides your position, including the retention of the original design.

 

Box, do you have a link to the XF bolt spread measurement pics? I can't seem to find them after searching.

I'm in the camp of thinking the CATS are more of a gimmick. If you were to give me a car with CATS and one without I most likely wouldn't be able to tell the difference. Now for those of you that tear up the twisties or drive the car hard, I'd imagine it may be hard to replace for you. Me, I drive like a grandpa. I'm sure we could argue over stability control in the case of emergency maneuvers and such, but would we ever know because no two cases are the same. The majority of cars don't have a similar feature, so we could also argue all the other cars being unessessarily safe because they lack this function. I suppose it really comes down to price and whether it is worth it to the consumer.

I was able to find the CATS compatible S Type struts online.

Bilstein, Innovation and High Quality Since 1873

At roughly three times the cost per strut versus the non CATS Bilsteins, I guess the price difference would be up to the purchaser. It's a cool concept, but personally, I can't see a huge reason for a daily driver to pitch out an extra 200 or so per strut to have it.

With what they contain, I think the Strutmaster kits are good over the counter, no fuss setups. I agree one could possibly build a better coilover for roughly the same price, if you could manage to fit all the parts together. For the average consumer for a daily driver, I would imagine the Strutmaster or similar setup would suit them well. For people that take their car to the limits, perhaps a custom build, or a CATS compatible setup would be better.

 

The CATS Bilstein are 20-070854 AND 20-070885. i need to see what local gets for these.

 

CATS isn't a gimmick, in fact, major manufacturers have been adopting these types of systems in their vehicles for the last decade, even the Big 3. It doesn't take long for owners of Strutmaster conversions to tell you how increased body roll comes into play after their change, and that in itself tells you how much of a "gimmick" it is.

What amazes me, is that folks would purchase a $70k+ vehicle and want to spend virtually nothing to maintenance it. It is your vehicle, and you can do whatever you wish with it.

 

Here is the answer to whether or not the XF's strut plates will work on our cars without modification. Davetibbs was kind enough to measure the bolts in his 2010 XF supercharged. The answer is no, it requires modification just as the S Type strut plates do.

https://www.jaguarforums.com/forum/x...rement-172254/

 

What about the top plates from the X351, since Jaguar already changed the shock assembly from air to coilovers? From what I've read the new XJ is an evolution of the X350/X358

 

Good idea, the x351 front top plates might work. The rear on the x351 are air shocks, so I suppose you may be able to use front strut plates from the x351 on all four corners of the x350.

I'd have to check to see if the top plate bolt pattern measures the same on all four corners of the x350, or if it varies front to rear.