Wow, you have ALL the toys...

 

But, what real life difference do they make?

 

Good question,

Jgaxkr, do you track the car and was it flexing somewhere, or have you found that all the extra power from the twin screw was causing flexing??, or did you just put these braces in as insurance to keep things tight?

Inquiring minds want to know.

 

I just installed this shock tower brace (UR-TW2-1543) on my 1998 XJ8-L 4.0

The bar aligned to the bolt holes nicely, but had ZERO clearance (was hitting the intake manifold).
I needed 2 washers under each bolt on each side to increase the clearance to an acceptable amount.
That being said, I felt a great difference in the feel of the car. Front of the car felt slightly more responsive, and I hear much less creaking/chassis flex on the road.
For $158 out the door, and how easy it was to install, I think it is a great upgrade for X308 drivers (especially non XJR/Sport owners - Base model and L have less chassis bracing)

I will add an OEM rear anti-roll bar from the XJR to further reduce chassis flex/improve ride quality (Ultra Racing has their own rear brace for the car, but I will use the XJR unit since it was designed/engineered for our cars in the beginning)

 

Do you know what additional chassis bracing the XJR has?

 

XJRs have front and rear roll bars, vs only a front roll bar for the base model/L. Maybe someone can chime in on how different the chassis are between the two cars...

 

There are no chassis differences, just sway bars as you've said.

Other that, the springs are firmer and lower (except possibly in the US?), and the shocks are firmer too.

 

X308 XJR chassis is totally different to the X100 XKR chassis. The X100 is based on the old XJS floor pan.

 

Towerbar in my car.

This item changed my life with the xjr. Coming from Mercedes the rattle on the dash and fibration of þhe front of the car made me ill. After the installation this much better, now I love her outside and driving. The effect on the road holding is evident for a sensible driver as the car not moves in itselve at the front and it gets more precises.

Someone here sad it wouldn't have any effects but I have other experiences.

Best Pagodino

 

I just finished writing a long explanation about suspension geometry and the difference between a strut based front end and and one with shocks, but decided to delete it and just tell you to enjoy your "towerbar."
Vector

 

That's a shame, I would've been quite interested to hear it.

I understand the basic principal though. We have double wishbone front suspension, with the upper and lower arms, and the spring, all attached to a subframe. The majority of the load through the suspension goes to this subframe, and not up through the shock to the chassis. This is why bracing the top of the shocks is largely irrelevant.

There will always be some flex though, surely? But, as per almost every other post here, it just doesn't seem like it would really make any noticeable difference.

Luckily on XJR's there's so little clearance it's basically moot anyway

 

I have come to be less sceptical of the concept since my original post.

If you look at enough chassis diagrams you come to realise that the
suspension loads are directly borne by the subframe. However, the
subframe in turn puts a load through the vee-mounts into the front
body structure just below the shock mounts. Bracing of the top
of that structure cannot help but prevent movement in the area
to some degree.

As for the rear bar shown by JgaXkr, it is reminiscent of what is
used in some vintage racing E-types. The whole rear end subframe
is a bunch of pieces bolted together depending on four rather flexible
mount points. Location is rather iffy, so just about anything is going
to help.

++

 

For reference, what is the vertical distance between the bottom of the bar and valve cover at the top
edge of the coil cover? That distance is the same whether the car is or is not supercharged.

Knowing that distance will allow owners of the XJR to decide whether the bar will clear the
top of the engine.

 

First off....why would you want to?
Besides looking effing fuggly and impossible to shut bonnet/hood.
The only purpose of this waisted exercise would be for misguided
pose value ;o]

 

I think claiming that the hood won't shut is a bit overboard.

Besides stiffening the body structure to which the subframe
mounts, it might be a dandy in-situ engine support when
removing the subframe.

 

I still do not understand how this could work, and after looking at your photo I am even more confused.


You state this item changed your life with the XJR, But where is the supercharger in the photo???


Never having tried this device I would not condemn anothers experience with it, but I do suspect a large dose of the placebo effect is in play.

 

thank you

 

Looks a bit thin and flimsy to provide much stiffness, it would simply flex up in middle, if there is really any load applied to it.

If that is a picture of the bar in your car, you don't have an XJR you have an XJ8 or your supercharger fell off somewhere.

This has been discussed before and the consensus is that it won't fit in an XJR engine bay, the supercharger sits on top of the intake snakes and touches the top of the hood liner at the back under acceleration anyway.
Vector