I stumbled on this photo of an '02 Aston Martin Vanquish, and reaffirmed my ability to reinvent the wheel.

That sure looks like a carbon fibre strut tower brace to me: I had asked the guy who is making C.F. ashtray lids about the suitability of the material for this application, and there is the answer. My thought was a larger assembly that also ties into the cowl, but even a simple fabrication like the one pictured would help to stiffen any XK, and might even reduce the cowl shake that Gordo has correctly identified in his convertible.

If nobody is making these for Xk's yet, and I have never read of one, they should. Thoughts?

 

A bolt-on application part would be pretty sweet.

 

Would the one from an Aston fit the XK? Isn't the body style the same or "pretty close"?

 

Valid point, it's hard to tell with the V12 tucked in there. I thought they were built on the same floorpan... it might be a direct fit.

 

im sure some one could make one...

i have allot of friends who do metal fab and custom fab for a living..
if not carbon fiber maybe Stainless steel?? or something polished...

 

Yes, I'm sure that could be done as well...it just seemed a bit easier to shape the brace for underhood clearance by moulding it. So long as it was of sufficient strength, the C.F. seems like it would be lighter and easier to mass produce. Guess we'll have to settle for ashtray lids.

 

well, i just talked to my prototype fab buddy, he said "hell ya im game" so we will work on one soon. stay tuned!

 

Must be strong and light, I don't need any more weight bringing my nose down (and my camber out) any more than it already is.

 

totally agree with you on that one.. ill let ya know. and ill post pics..

i don't know why i didn't think about this before.

 

I'm believe I'm experiencing the same shakes as Gordo, jitters after bumps. I'd be interested in this item if it's ever made available and cost isn't galactic.

I've seen aftermarket front and rear sway bars available. Think they would help if they were thicker than oem?

 

I don't think a STB would solve my cowl shake. The issue is body flex front to rear, caused by removing the roof structure. An STB will lock together the two shock towers to keep them from moving inboard/outboard. But that will do nothing for flex between the A-pillar and cross members behind the rear seat. I need a thicker trans tunnel and/or stronger rocker panel subframes.

BTW the material of choice for an STB application would be extruded aluminum. And it would have to closely follow the manifold profile. There isn't much airspace between the top of the plastic manifold and the engine blanket on the underside of the hood...er bonnet. I have the same fitment issues on the STB in my 300zx

 

Would something like a thicker aftermarket x-brace help to minimize the shake? Such braces are available for BMWs and S2000s.

http://www.inlinefour.com/spoons2chasx.html


Since the XK8 still has bits of the XJS, I found something called the "V&A Spiteri cruciform brace" mentioned in a XJS auction, which I suspected goes underneath the middle of the car rather than the front like the current XK8 x-brace:
http://cars2.ebay.com.au/Jaguar-XJS-...mZ140307657555

Upon googling, V&A Spiteri is an Australia company that handles Jaguar parts, but it's website doesn't provide much info, and none at all about this cruciform brace.

And I found this bit of info:
http://www.justanswer.com/questions/...-1990-xjs-conv

This can all be moot if these XJS parts are incompatible, though. But maybe someone has an idea or some leads to further info?

 

Your vert should already have the cross bracing under the engine bay. It is a large 'X' bolted to the chassis on each corner.

 

Geez Gordo, I told you a year ago to weld your doors shut and be done with it. As for the "STB", it just seemed like a more viable suggestion, after seeing that Aston had already concluded it was beneficial. The one in their pic smacks of $800 to my eye, but making a cast alloy piece to clear everything and still fit under the bonnet looks like a more elaborate job.

 

Doors are overrated. What kind of welding rod should I use?

 

this is just me thinking out loud, but what about a metal bar in the cabin that ran over the rear seats which are relatively useless for carrying passengers anyway. And it could also support as a platform for a wind deflector.
http://www.climairuk.com/climair/pro...productid=2804

Kind of like the wind deflectors available now for the convertible which install by the seatbelt posts. Rather than screw in the bar, perhaps another juncture point that would provide structural rigidity or weld that bar in there. The rear seats could also be entirely taken out like the latter day 1980s Fiat/Pinifarina Spiders and just replaced with a carpeted shelf.

 

It's about triangulation of loads: you can weld a roof on, or build a roll cage. A phrase form road racing, used to identify a particularly useless drive: "Time to triangulate the center bay".

 

Montauke: the flex is longitudinal... front to rear, hence any bracing would need to be running in the same direction as the length of the car. STB and rear bulkhead bracing is side to side.. not end to end. Furthermore, any stiffening of other parts of the suspension and chassis would only serve to emphasize the flex in the central core of the unibody. gordo

 

Ah, thanks for the clarification. Looks like I'm going to have to weld the bar at the clock and the center of the trunk, running it between the seats. Kidding.... :-)