This is my first Jag, coming form Mercedes 500 E and others it is a different world.
I love the car, it is a little anaconism, old look and new tech...what is perfect for me!
There are some litlle points where I want to modify my car. It has only 50000km (30000 mls) and 18' Asteroids. The irst thing I fell is that it is a little flexing in the front-chassis, hope this will get better with the UK tower bar. The roadholding is good but driven hard it is not very confindential, first there is understeer and with not good roads the rear tends to jump and steer a little. What I am looking for is a stifter front sway bar, lower springs and registable shocks.
Is there an original thicker sway bar in the XJR or somone producing a kit.
Worth using PU-Bushings all round (Powerflex-Andy...)?
Springs: I would prefer progressiv springs (Amesh, HR....)?
Shocks, nothing from Spax?


Best Patrick

 

You could fit a rear sway bar.
Replace bushings.
There is an Asian company that sells front and rear sub frame braces.

 

The tower bar won't do anything other than dress up your engine compartment. The geometry of the front end precludes this part have any effect on the front end.

I am going to give you the answer I usually give to someone who wants more power out of the NA V8:

I think what you are really after is the entire suspension system from an XJR, it is much more stiff and holds the road a lot better than the XJ8 suspension at the expense of some comfort.

It may be worth it, and less expensive in the long run, to sell your XJ8 and buy an XJR. The extra horsepower is worth it and while they are not easy to find, there are low mileage examples of the XJR out there for some very attractive prices right now if you are willing to look hard and be patient.

The XJR also has the more robust Mercedes tranny, electronic suspension on some models (there are good and bad points to this option) and is usually optioned out to the max so it it is usually more than worth the price difference.

You can turn a sows ear into a silk purse, but it is usually easier to just go out and buy the purse pre-built. Plus the silk purse is engineered to be a purse from the start.

You can also get some good results by pumping your tires up to "race pressure.' It limits the sidewall flex and makes the car much more responsive. You can research what this might be for your particular tires, but it is usually much, much higher than "street pressure."

Pic below of my XJR holding tight through the SS's at Road Atlanta.
Vector

 

I looked back at your old posts, and the car is variously described as an XJ, and an XJR. So which one is it?

 

try bars from ultra racing

 

The 18" asteroid wheels hint that it is an XJR.
Vector

 

I found an older post where he upgraded from 16" to 18".

 

Buy an XJR. You'll be swapping to everything the XJR has for suspension anyways, may as well have the additional power and stronger transmission. I'm assuming from here on out you're starting with an R.

- Polyurethane bushings are always a good idea if you want increased response at the cost of NVH. The Powerflex stuff is very good, if a bit expensive.

- No one makes aftermarket sways. I'm making my own, and it has not been at all easy.

- A few companies make lowering springs. Mina, Paramount, and Arden are the more common ones. Most are only marginally stiffer than stock, ans lower the car about an inch. Not a bad idea, lowering your CG is always better for handling.

- No one makes a really good aftermarket shock for the X308. But, the factory Bilstein sport shocks are actually quite well damped. Not a whole lot of room for improvement there.

- Not many gains to be made from braces. Being a double a-arm front suspension where the damper has no spring force on it, a shock tower brace literally does nothing. Same with the back. You'll get much bigger gains in feel and response in the front end from stiffer bushings, as the main problem is too-soft bushings in the front subframe-to-frame joints (the whole front suspension is attached by 4 big squishy bushings) and the bushings in the a-arms (especially the lowers) are too soft and allow too much geometry change.

- Basically, your only "easy" upgrades are going to be lowering springs and poly bushings. The Jags just never get the aftermarket love other makes do. If you want to go deeper than that you're going to have to do some custom work.

 

Yes,first I bought a Xjr in summer but sold it after 6 weeks and gained nearly the double. So after 2 month I found this Xj 2001 with 30000miles 50000km, nerly perfekt black in black. Bought some Asteroids and there it is. Only if I could find one of the 57 manual LHD xjr x300 with a sunroof could make me a swap.

The tower strut is not for better roadholding bit the front chassis is week. So I will use Pu bushings and HR coils with Bielstein dampers.

Next point is to get more space ore netter ergonomic for the trottle feet. I think to make me a larger, higher and nearer to the brake positioned pedal point.

Best Pagodino

 

The XJ8/R's do not use front struts, which usually benefit from a strut brace, they use conventional type shock absorbers.

As many of us have told you, this mod is purely cosmetic and will do nothing for chassis stiffness or suspension geometry. It does not address any "weakness" in the chassis, the geometry simply doesn't work this way. You might as well tape a broomstick between the tops of the shock mounts.

A "strut brace" looks nice when you open the hood, but it is not worth the money unless you are simply trying to dress up the engine compartment.

Adding some custom/race type pedal covers will help with the tiny throttle pedal without having to re-engineer the pedal mounts. The guy who built my covers will make them any shape or length you want.

See pic below.
Vector