Has anyone had any experience (good or bad) with the UltraRacing Strut Brace?
Does it make the car feel more solid?

Ultra Racing 1 PC Solid Front Rigid Strut Tower Bar Brace 96 06 Jaguar XK8 X100 | eBay

Thanks.

 

I saw that awhile back. Im sure it would decrease twist in front end however does it even fit?

 

Strut braces by nature reduce some of the flex that naturally occurs between the strut towers under (hard) cornering, so a good brace solidly mounted to chassis points will add some degree of stiffness. With that said, your first order of business should be ensuring your suspension bushings and other components such as struts are still serviceable and in good working order. New bushings on control arms, sway bars and steering racks make a huge difference in the feel of the car and may cure your issues.

 

Got one for my XKR, it didn't fit well and I wasn't convinced it was sturdy enough to modify it. It'll fit an XK8 but it really didn't look sturdy enough for me. Going to poly bushing however, now that firms things up nicely.

 

its perfect a vast improvement,hear is a pic of the brace fitted to mine,only takes 15 mins to fit.

 

The best improvement is larger rims and tires with an aggressive alignment

 

Well, I decided to buy the brace (I figure I've spent more money on many more frivolous Jag items), so this will either be end up being a tangible improvement in overall body stiffness, or a little bling for the engine compartment. I'll report back after I receive and install it.

 

Don't think such a brace will achieve very much.
Strut Braces can help on vehicles with mcpherson strut suspension as the spring/damper unit also provides some suspension geometry control, on those vehicles, a lot can be gained by linking the lower Wishbones" if they are lacking a decent subframe.

On the XK all suspension location is controlled by the cross member casting. This in turn floats about relative to the body on front mounts which seem to stand the test of time, and VEE mounts at the rear. These do delaminate and become sloppy, so turning the steering wheel may move the wheels as intended or just flex the vee mounts - which are close to the rack mounts.

Another thing to bear in mind is that the front cross member also carries the weight of the engine so this is passed to the springs partially by the lower wishbones. As cross member mounts deteriorate, less weight is supported by the mounts, thus increasing what could be regarded as "unsprung weight" This is very bad news for handling.

A suspension overhaul should include VEE mount replacement is these are at all suspect. On my XK8 I used the original VEE mount aluminium components then cast polyurethane rubber to make a stiffer mounting. Car now handles much better.

 

How did it work out for you? I'm thinking of buying one, have heard some good & some bad things & wanted to know from someone with real experience of it.

 

Looking at this offering I would have said that it's next to useless. The secret to body bracing is triangulation - and single plane link bars like this can't work effectively. About the only thing they might do is stop the two turrets from squeezing towards each other (which is never going to happen anyway).

However, you could hang your pants to dry on it, or drape a herring over it for perfect kippers after a 100 mile blast!

 

I have one on my Saab & it works brilliantly- I want to know from someone who's fitted it whether there's a noticeable difference on XK8s.

 

Doesn't the Saab one brace back to the bulkhead ('cos the Saab bulkheads crack by the steering rack)?

 

As other have mentioned, the strut brace is especially good for cars with McPherson strut suspensions, because the top of strut defines part of the suspension geometry. The geometry on a double A-arm, like the XK8, is not going to benefit as much.

However, general chassis stiffening is good, though for the weight there might be more efficient options. In my experience using FME on race car frames, triangulation is necessary on cars to get any meaningful amount of stiffness for the weight.