Hello all, this is Andrew from Jaguar Specialties. I've been tinkering with XK8's for a little while now, and started to look at suspension pieces.

I've had my sway bar bender take a look at the bars of this car and make some recommendations. Since the front bar is already 1", and the way it is installed in the car, there probably isn't much to do there. However, on the rear, he thought upgrading the size from the stock 11/16" to perhaps a 7/8" diameter could make things more interesting. Anyway, I had him make up a couple, and here is what he did.

Upgrade bar #1 is basically a direct copy of the stock bar, with only and increase in diameter. It would mount to the car using new brackets and poly bushings, and then the stock end links.

Upgrade bar #2 is also a very similar unit to stock (again 7/8" diameter), but instead uses more traditional end links which may be helpful in adding preload in one direction or the other.

Below is a pic of the 2 units.




Ultimately we'll end up creating a new product here, probably priced around the same as our other sway bar kits- around $230-$250.

I'll get one of these on the car and let you know how it goes. If anyone else is interested in trying one just for fun, send me a PM...

Thanks

Andrew

 

Dang, and I just bought one of the Ultraracing 20mm bars...

Think there is any opportunity to make it adjustable?

Might be difficult with the stock end links, but maybe possible with the more traditional style.

 

A very nicely made product and competitively priced; you should get some interest for sure.

 

Will be watching this like a cat on a mouse. Well you get the point! LOL Good thing I waited in purchasing the other bar. Let us know about the final outcome(ride harshness, adjustability, and final color(red would be a nice option).

 

Hello all- boy how time flies. I just realized it's now early May and the last we talked about the new XK8 rear sway bar was the end of Feb. Sorry for the delay- just as we were getting ready to get one of the new bars on the car, the trans cooler failed in the radiator. Luckily, it was the radiator that filled with trans fluid and not the other way around. A messy cleanup, but not a disaster.

We've had one of the upgrade bars on the XK8 test car now for a few weeks and so far so good. This particular bar was the unit that used traditional style end links rather than the factory style. That keeps overall costs low and they are very simple.

Attached are a few pics of the bar installed, with clear views of the end links on either side. Note- the production bars will have slightly altered end lug angles to better correspond to the lug on each trailing arm. Also, the end link hardware will be more finalized- these are really just quick and dirty parts for testing....

We'll put some more miles on it in the next month or 2 and then fabricate a few more to be sent out to customers willing to test them for additional feedback. If you're interested to be involved with this, please send me a PM

Thanks

Andrew
Jaguar Specialties

 

very interested to hear how behavior is affected, namely reduction of understeer so it becomes more fun in the twisties (I miswrote earlier, clearly we all want less understeer)

 

So far the bar is great- not overly twitch as far as I can tell.

Note- increasing the rear bar stiffness (larger diameter) will increase oversteer, not decrease it. That's the nature of it. If that's what you're after, then the bigger bar is for you. If not, it's probably best to stay with stock....

 

Avos has re iterated that a smaller rear sway bar will increase traction and that a larger bar is going to increase lift of the wheel and decrease traction further on the standard rear open diff in another thread about improving chassis stiffness and handling by member Sentinelist.

What are you discovering on your end?

 

Thanks for following up on this. We don't typically mention traction and the the effects of a rear sway bar (oversteer) together. Yes, absolutely right, a larger rear sway bar induces more stiffness in the rear suspension, ie, the tendency to lift an inside wheel on a turn. If you mean traction in that sense, then we are saying the same thing- lateral traction, the ability to keep the car from sliding sideways. I suppose it would be better in a more powerful car with a larger rear sway bar to have positraction/limited slip so power is always going to the wheel with the most grip. But that (on the limit) situation occurs very infrequently, where as the main goal of the sway bar (limiting body roll) is something we take advantage of on every freeway on-ramp clover.

Back to the bar itself, I've been driving the car for a while (in typical every day situations) and the bar is great. It's not a huge increase in stiffness (not as if putting a bar like this on a car that didn't have one originally, like the sedans), but it seems to be incrementally stiffer. And this is on a test car running 20" wheels and 35 series tires. Whatever the bar is doing, I'm feeling it.

We'll have the testing go on a little longer and then do a short initial ruin with more finalized hardware to send out to beta test customers. If you're interested to be involved with that, please get with me off-list (send me a PM)

 

I recently had my electronic 2-stage CATS shocked modified with a simple switch that puts the system into firm mode, and firm mode in tight canyons is handy but way too much to live with driving around as it makes the suspension bouncy.

My interest in the rear bar has diminished a bit as a result except for the fact that something in my rear suspension squeaks over uneven pavement so very likely I have to get new bushings back there despite nothing visual showing up. In addition, my general purpose mechanic likes the idea and when given a choice between the UR 20mm bar and your bar he voted for yours since you are dedicated to Jag.

One knowledgeable person who doubled his rear sway bar (CoventryWest) noted it made the steering sharper too, and I would love that. I'll bet Sentinelist is with me on that as a former Porsche person. I already had a switch installed on my car that leaves the power steering greatly reduced in limp-home mode, and I've happily driven it that way for a year. Normal boost is too much and reminds me of 80-90s era Cadillac sedans.

 

I'll keep my eye on this from Jaguar Specialties- am looking at a fall-winter timeframe to get the car in better shape, literally. I will probably tinker a little with the steering boost and perhaps re-enabling the CATS system soon to see what that does. The latter's module is simply unplugged in the spare tire area- I'm assuming just reconnect and hope it doesn't throw a code? I believe it's on the stock suspension, though the control arms may have been swapped at some point... Sharper steering would certainly be welcome.