I am replacing the "small" bushings on my radius arms with poly. I have gone through at least two rubber ones (maybe three?) on the right side. The first one was my fault - I tightened the thru-bolt down with the suspension of the car. The one that's on the car now is fresh. I have less than 1,000 miles on it and it's already showing signs of fatigue/cracking. It's worth mentioning that I have a cammed LS1 V8 under the hood and drive it as such.

I decided going to poly would be a good idea. I see there are two options: one by Polybush and one by SuperPro.

Polybush. Made in UK. Price to me about $132/pair. This style has the center steel tube bonded to the poly bushing.
Rear Radius Arm Bush Small


SuperPro. Made in Australia. Price to me about $50/pair. Here, the center steel tube is NOT bonded to the poly bushing. It appears to be an interference fit but I just don't know.
SuperPro Parts

Any thoughts on either of these? Any experience with either product?

 

In the land rover world most prefer the superpro as it is a softer/more flexible compound than the others.
Ironically for me in Australia it is cheaper to buy the Australian made product from overseas than to support local[and get screwed]

 

I used Superpro because that is what the guys that race XJS's in the UK use.

If you have more than 400hp you need to reinforce the rear end or you WILL break the mounts.

I have attached a picture of a Lister XJS rear end, these were fitted with additional A arms and chassis rail mounts to strengthen the rear end.

 

hi fastcat
I have stock radius arm bushes only because they are still ok only the front has superpro bushes everywhere and as I only do about 1500 miles a year they will probably perish rather than wear out, in your case, with the extra power you are using, if you fit poly you will probably put strain the next weakest point as warrjon says the whole rear end needs reinforcing to cope, sorry I cant be more specific,

 

Thanks for the replies!

I have a plan in the works for a brace that goes from the bottom of the IRS to the trans tunnel. What I'm more concerned with here is the difference in design between the two poly mounts.

 

If Super pro is good for these guys, the reason I used them, apart from I am in Aus

SUPER PRO SUPERFLEX POLYURETHANE BUSHES

 

Didn't mean to hi-Jack this but what do you reinforce on the rear end. I am building a 500hp 383 stroker motor for my XJ6 right now. I am currently rebuilding the front suspension and I am using super pro bushing. I am heading to the rear end next and while it's out I need to know what to make/build to reinforce it. Any one have any pictures explaining what was added?
Any ways the super pro stuff looks of great quality I haven't driven the car yet but I bought a complete kit for the front and rear from eBay I think it was less than 400.00 us and came with everything.
Jim

 

No problem.

I have poly bushing in the upper front WB's and these are coming out at the next opportunity. They will not last very long 20,000km at most. Go rubber in the WB bushes. What I have found is my upper WB bushes have worn the tube badly and will need to be replaced soon, they have about 10000km on them.

Use Poly in the rack, front subframe round mount and sway bar (although this will eventually squeak).

If you google XJS Lister KWE in the UK have a one restored and a great photo gallery. The rear end needs to be braced from under the diff to the chassis. Best way is to brace from the inner fulcrum points to the chassis rails just behind the gearbox.

I have had a good look around a Twin Turbo XJS V12 race car and this brace runs under the diff to the boot floor, the floor of the boot is rippled from the movement of the cage. This car does have 300mm slicks and enough torque to break 2 Jerico race boxes.