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Guys
From time to time there have been discussions on here about whether the rear anti-roll bar (sway bar) is needed, and if it makes the car corner and handle better or not. Jaguar sometimes fitted it during the production life of the car and sometimes not. I am of the firm opinion that the car handles better without it, but obviously opinions differ.
Well, I present a very interesting interview with Norman Dewis, the famous Jaguar test Driver, and members of the Jury, I rest my case. There are also quite a few other interesting clips involving Norman Dewis on Youtube.
Great info right 'from the horses mouth' ! If you're looking for a reason not to install a rear bar, you have it!
However, in the car world there's virtually unanimous agreement that what works best on the race track isn't always what works best on the street.
No disrespect to old Norman but I certainly wouldn't want to give up the benefits of the rear bar for street use just because it didn't work well on the race track.
However, having done some experimenting with different rear bars on my XJS I can attest that the larger ones can indeed have scary results.... but found only positive results to the small sized bars used by Jaguar (13mm and 15mm as I recall). Norman mentioned that, after it was all said and done, the final decision was to go with a thinner rear bar but made no mention of how the car behaved with it.
I can see that Daim, and the bell cranks, but I am interested in how the mechanism is attached to the suspension underneath.
We designed a rear cantilever set up that mounts in the trunk and connects to the factory lower control arms. This gave us all the adjustability of modern suspension that has never before been available to Jags of this era, with adjustable ride height, dampening, preload, and spring ratio leverage capable of being adjusted from inside the trunk.
No pic of that though. the link under the pic takes you to the article. It’s a good read. Turboed the 4.2, made 390hp until they broke it, no SBC swap here they rebuilt another 4.2 and are north of that hp figure now.
By the end of production, all XJS were using the ZF rack. I THINK it was introduced on the 4 litre (and possibly the 5.3) some months before the introduction of the 6 litre in May 1993. Certainly there's a part number changepoint on 5.3 racks at VIN 185820.
Interestingly on their website, Jaguar now show a supersession of part numbers for pre-facelift cars, from the early racks to the later ZF racks, implying that they are straight replacements and will just drop in. I had read somewhere that you need to slightly bend one of the metal fluid pipes to fit the later rack to an early car, but I'm not absolutely sure.
Rather than go and crawl under my own ZF-equipped car, I found this much cleaner pic on the 'net which indicates a ZF nameplate.
Doug
I changed my rack to a ZF one about 20 years ago. It is a direct bolt on replacement, except for the actual fluid pipes which are not idential. The ZF pipes fit the pump and cooler the same, it is just the rack ends which are different, and the pipe routing.
It is clearly marked ZF and has a one-piece all aluminium cast body.
After a certain date (I think about 1994, but I am not sure) all XJSs were fitted with it. The fitment to the subframe, bushes etc etc are all identical. In my view very worthwhile upgrade, made even better if you fit a 15 inch diameter steering wheel in place the the (pre-facelift anyway) OEM one.
My car is RHD, but attached a couple of pics of a LHD rack I helped a friend put in.
10-15-2019, 03:00 AM
The great rear anti-roll bar debate
