I want to do a serious upgrade to my xjr. So far I have bought bilstein shocks, new ball joints, and a set of H & R springs. What I'm having trouble finding is polyurethane bushings. Where are they and can I buy a complete set?

I am really considering the engineers solid bushes for the top wishbone connection but $475 might blow my buget so what are my options? Who makes a complete kit? Super flex and power flex does not actually have all of the bushes listed for the uppers and the lowers. Am I look ink at the website wrong? Has anyone completed a full poly set up on a XJR?

Ryan

 

AFAIK, there is not a complete set of off-the-shelf poly bushings as a "kit" for front end of the X300.

As you noted, Superflex and Polyflex have several of the bushings if you pick/choose and combine from their products, but not all bushings are covered.

I'm surprised that you found someone that sells aftermarket springs for the X300 after all these years, although frankly I've never looked

There are quite a few threads on the forum, including different model sub-forums, where owners have installed poly bushings and they provide their thoughts. You might try a global search for "poly", "superflex", "polyflex", etc

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I think the H&R springs he purchased are the 1.5" lowering kits?

If these are the springs, compounder, would you post pictures after the install and your thoughts on the changes?
Thanks!

 

Yes they are the H and R springs. I ordered them and should get them in about 2 weeks. If everything goes right I plan to install new springs, shocks, front and rear bushings, and redone wheels and tires in January. I will post pics for before and after.

 

Lowering springs?

The X300 has non-adjustable camber. I think there might be a problem here. Did the vendor make any mention of this?

Cheers
DD

 

Also, with my new 245/50R17 tires for example, I'm not sure there really is much room for a 1.5" drop before things like the fender edge might rub on a good bump if the wheel were turned


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These are the springs I think he purchased and what I was talking about...
29576 H&R Sport Springs - Lowers Front: 1.5", Rear: 1.5" for at Andy's Auto Sport

 

There probably will be some scrubbing going on but I plan to deal with that when I get there. My car is in bad shape an not really worth trying to keep pristine so I figured that I might as well have fun with it. Right now I want to make it handle like a heavy sports car and I'm willing to deal with a rough ride. I have lowered almost every vehicle I've ever owned and by no means recommend it to anyone. My car also has 210k miles on it and think it has sagged at least 3/4 of an inch already. Lol

The springs I bought are the H&R 29576 they supposedly lower a XJ6 40mm. Are the XJR's any lower than the XJ6's from the factory?

 

Well how-a-bout that

.... I'm really surprised someone makes lowering springs for the X300 given its low production numbers and vintage.... ever did and most surprisingly STILL DOES!




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I ordered them a month ago so they are taking a while. I wonder if anyone has ever bought a set. HMMMM

 

They probably make them to order, per order or a few sets at a time. Probably not high demand.

All they need is the spec, and they put it on the machine.

You can have custom springs made this way from folks like CSS. You just have to give them the specs like unsprung height, diameter, gauge, rate...


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XJ40/X300 has no front camber adjustment, though I have considered designing some fixed blocks to mount between the top wishbones and top ball joint to change the camber. However, so few people change the ride height on these cars that I don't think it would be worth the effort. FYI, the ride height at the front should be 153mm under the front cross member and 160mm under the rear edge of the "A" frame, with a +5 to -5mm tolerance.

 

 

Be sure to get some before & after exterior photos of the car, and measure the actual before/after drop so those thinking about doing this can reference this thread to see how it works out.

Replacing the springs on the X300 isn't rocket science, but it is a bit of a chore compared to other cars.

Check out the "How To" for replacing the rear shock thread as that covers removing the rear springs. Since it is such a big job, I'd recommend also replacing the rear spring/shock bushings and possibly the shock itself while you are in there.

Here's that thread:

https://www.jaguarforums.com/forum/x...ent-how-62143/


There are some threads on replacing the front springs, and a post here or on Jag Lovers on how one can make the special tool required as normal spring compressors apparently can't be used since the front XJ springs are installed in an "arc" instead of straight. The factory spring tool is available too, but very expensive.

However, again, trying to use normal spring compressors on the front is apparently very dangerous.

Jaguar SPRING COMPRESSOR TOOL, FRONT SUSPENSION - JD115-OE

https://www.jaguarforums.com/forum/x...pressor-82083/

Jaguar XJ40 project: Front spring compressor tool

http://www.xj40.com/viewtopic.php?f=24&t=3733


There's also a thread here somewhere where someone made a very robust homemade version of the tool for the front springs. I tried to find it quickly, but didn't. Maybe you can with a bit of searching.

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I will take measurements and lots of pics.

Al...... I really appreciate your insight and help. I have read through all of the links you gave me and I am starting to form a plan.

I have read a tutorial on how to do the rear springs by 'black onyx' and feel like its the way to go for me.

Thanks for all the help.

Ryan

 

Any updates on this?
I've finally gotten my XJR running mechanically sound so now it's time to look into upgrades and thinking about these lowering springs if they actually do work out...

 

I have been busy so I have not had a chance to tackle the springs and shocks. I will post pics and a review as soon as possible.

 

Thanks for the update. I'm thinking about either engine or suspension mods next so I'm curious to see how it would look with it lowered

 

Finally finished up my suspension. The car really handles great now. No more clunks and leaning at every turn. Here is a quick review.

Shocks- Bilstein HD Typical excellent Bilstein feel, not to stiff or soft. They seem like the harder you press them the better they are. Very smooth over rough pavement but when turning aggressively they are firm.

Springs- H&R These are 45mm shorter than the factory springs but just as I expected my car sits about the same as it was since it was sagging horribly. The springs are definitely more firm and give the car a more solid feel. Between them and the shocks my car now turns flatter (no dipping) and seems to react much faster to steering input.

Bushings- Powerflex and superflex I used both to try and get all of my bushings changed to poly and spent over $800. I'm really happy I did because they were a pain in the a$$ to change and hopefully that will be the last time I have to mess with them. I have a lot of experience in poly bushings and have went to them on several vehicles and they are all about the same. I can feel more of the road, transmission shifts and engine revs. I really like that and it reminds me of a BMW feel.

In short I really recommend all 3 of these upgrades not to mention the Andy's sway bar drop links which I also believe helped with the flatter feel and steering response. I don't think the car rides harsh at all. I am very satisfied with the ride and feel of my car now.

Keep in mind I may like my suspensions a little on the firm side. Here is some of my old cars / trucks.

1991 300ZX Turbo, 1972 Corvette, 1991 Chevy 454SS, 1992 GMC Typhoon, 1987 Mustang GT convertible, 1993 Mustang GT, 1996 Impala SS, 1994 Ford Lightning, many Honda CRX SI's, 1995 Acura Vigor, 2002 VW GTI, 1997 GTI, 2008 VW Rabbit, ect.

If anyone wants or needs a spring compressor tool I have one that I made that I would like to sell.

 

Sweet! Can you post a ride height pic? I am not far behind you on this, however, I will go with rubber bushings as the cost isn't worth the value of the car to me. That's just me though, if I "cared" more about the car or "less" about money, haha, then I'd go poly throughout.