Has anyone tried polyurethane bush kits on their cars, and if so, what do you think of them compared to standard bushes, and how long have you had them on your car?
I'm thinking in terms of a bush kit from Larkspeed on ebay, to replace my front ( and probably rear, at some point) suspension/steering bushes.
The bushes in question are powerflex.
Has anyone tried these?
Feedback on other bush makers will of course be welcome.

 

I installed Powerflex poly bushings on my 2005 XKR Coupe: front upper control arms, rear under beam and rear sway bar. The bushings are very well made and finished and very easy to install. The addition of the ploy bushings on the front upper control arms added just the right amount of handing response without communicating too much road feel. The addition of the rear beam and sway bar bushings really added handling control in the turns and again without adding too much additional road feel. I elected not to install the poly bushings on the lower arms up front and back because I had been advised by others that while the lower application added further to handling response it came at the cost of ride quality.

Enjoy the road ahead.

 

That's exactly the kind of info i was hoping for Goldlion.

Since i have to replace upper wishbone bushes and track rods , i thought i may as well get a complete kit, but was a bit concerned about the quality of "upgraded bushes" after reading another nearby thread concerning upgraded suspension mount bushes.

There's also a bush kit from Polybush, but these are £330 for just the front end, where as the Powerflex kit is £345 for both ends.
My car already feels really stiff when it goes over speed bumps. I would have thought that with the adaptive dampers and Jaguars reputation for ride comfort, the suspension would be considerably more absorbent than it is.
My neighbour has an XK8 just a year older than mine, and his car sits at least an inch higher at the top of the wheel arches, so mine may have stiffer shocks, or it's been lowered or something.
Makes your comments about which bushes to fit all the more relevant.
Thank you.

 

I have opted to replace the bushings as they need it and so far I have ONLY done the lower front control arms. I can say for certain that it improves the handling response and does increase the transfer of road noise somewhat. I haven't found that I gave up much in the way of ride quality, just a little more transfer of the road texture.

I do have 18" wheels with big balloon tires though, and could imagine a car with 20" wheels giving up a lot more in ride than in my case.

 

Sounds like a trade off between road noise and handling, so maybe the best short term option is just to do the upper wishbone bushes with poly's, replace the track rod, and see how she feels then.
Once i get the steering and suspension working properly i can experiment with ( hopefully) more reliable results.

 

I just had my shop install the full Powerflex bushing set on my 2004 XKR. This is a diffferent car. It tended to drift a bit on the freeway on rough pavement, not anymore. It feels lower for some reason and far tighter. Tossing it into a corner is amazing. I expected an improvement but not like this. No other suspension changes (didn't lower it). Wasn't cheap, about $3K in labor. I used the opportunity to put in a special X-Pipe and upgrade the rear brakes to drilled rotors (had done the front earlier).

Never really thought of the car as a track car, now it feels tighter than my S5 Audi. I'm not noticing a loss of ride quality either but it was always a bit more harsh than my XK8.

On the X-Pipe I used a silenced version and had already taken out the rear mufflers (Mina conversion). It actually made the car deeper, louder at low speeds (has a real rumble now) but quieter at full throttle.

 

Wow, so much for that plan!

 

Is that $3k in labour just to supply and fit the poly kit?

Theres a difference between Polybush and Powerflex, and Polybush are more expensive, but both companies make polyurethane bush kits for XK8's and XKR's.

The Poweflex kits are available through EBay for £345 (about $500-$550 approximately).
I'll be fitting mine myself as far as possible to save the labour cost.

 

Check Reverend Sam's video on Upper Wishbone Polybush replacement:


Sam had all kinds of trouble because the poly bushes he used were a different design to the OE and he couldn't get the washers to fit. Some posts on the forum report a similar issue whilst others don't. It could be one manufacturer is the same design as OE and the other isn't.

Graham

 

Already have

The Reverend cracked it in the end, the bushes have a thick side and a thin side, and won't fit the other way round.

 

The $3K US was just the labor. The full kit cost about $650 US additional. There was also an extra $240 to do a full front and rear allignment. They discovered an upper A-Arm bolt ($100 bolt) was bent in the process and replaced it, apparently it was a bitch to get out.

 

Sorry, you did say the 3$k was just labour, and Marsden even highlighed it.
My bad.

It's a lot to pay out on a 97 car, but not everything can be judged by comparative cost alone.
If you know you want to keep the car and consider it a significant improvement to your enjoyment of it, then who's to argue.

Personally i found mine handled quite well, but had a bit more body roll round fast bends than i'd like.
I didn't fancy the idea of stiffer springs because she'll already throw me up in the air if i hit a sleeping policeman (ramp) a bit too fast, so the polyurethane route sounds like it could be the answer, since the roll is only on the bends.

Truth be told i'd probably get a mechanic to do the dirty work as well if i had the spare cash.

On the exhaust, i assume the X pipe is the centre section?
Without looking it up, is it a 3 section exhaust, ie: downpipe, centre box(es) and tailpipes?
As far as i know mine has standard downpipes and centre section(s), and aftermarket rearboxes (i don't know what make).
It's louder from tickover to redline than my neighbour standard exhaust.

His one sounds oversilenced to me though, too quiet, like an XJ6.

 

What is interesting is my '97 XK8 corners like it is on rails, had no issue keeping up with a bunch of exotics in the twisties a few months back (except I kind of cooked the brakes). My 2004 was looser and didn't feel as tight, with the new bushings it is now tighter than the XK8 is. The XKR is already substantially stiffer, the XK8 even with new front shocks (didn't really make a difference) floats over bumps, the XKR more like my Audi you feel them.

Yes I removed the rear mufflers and put on the Mina pipe kit, the X-Pipe muffler (about $175) replaced the big center resonator. It actually made the car quieter (except that the welds are leaking at the moment and will need to be redone next week).

 

enderle i'm obviously in need of a brain transplant.
I was taking your car to be the 97 XK8 in your garage by your name in your posts, but you said

I've caught up now, i hope