Ultima Sports - suspension point failure on track

[fluxen]

Just an fyi for you guys; don't know if this part was changed on the GTR. Keep in mind that this part is on a 1996 Sports that used to belong to James, so it's seen plenty of abuse on the track in the last 8 years.

This failure occured going through a 60mph turn. I hit the kerb (not a particularly harsh kerb) at the apex, and the part collapsed. Since this part is all that connects the wheel to the damper, the car dropped onto its nose and I slid to a stop, fortunately not hitting anything. I've got in-car video of the incident, but I haven't digitized it or even viewed it yet. I may post it later if there's interest.

Now the pics:


Nice alignment, huh?

Hmmm...

a closer pic

and the resulting flat-spot

Packed up to go home...

All in all I was very lucky to not hit anything when this happened. No pics of this but there was a fracture that appears to have been there for a while directly opposite the wheel on the part in question. Those with older Ultimas may want to check for cracks on this part, before it fails in similar spectacular fashion

>>> Edited by fluxen on Tuesday 5th October 00:30

[shithotfast]

I had a very similar thing happen to my spyder a year ago. We have an "incedent" where I had the choice of hitting a pavement curb at 50mph or a car who had decided to do a U turn in the road without warning.

I hit the curb and my upright snapped at the same place. The castings dont seem to like direct quick thumps (fair enough!)seem fine in normal driving conditions but as with all castings I guess this is the weekness to expect.....

[gdr]

Nasty - glad car seems not to have taken too much damage. Checked my front uprights, circa 2001 - they look similar but don't have "Noble" cast into them - these must be earlier castings. Perhaps rose joints in front suspention transfer more shock load than road spec plastic bushes?

[fluxen]

shithotfast said:

I hit the curb and my upright snapped at the same place. The castings dont seem to like direct quick thumps (fair enough!)seem fine in normal driving conditions but as with all castings I guess this is the weekness to expect.....

Just to clarify, when I say I hit a kerb, I mean kerbing as in on a race track. It's nothing like a curb on the street, it's meant to be driven over (at least in my view)

GDR: Yes, definitely the rose-joints transfer a lot more force, I'm sure that's part of it.

[Boosted Ls1]

Piss poor casting if you ask me. I wouldn't like that one bit. I read a book which gave all sorts of information on how all this sort of stuff should be designed in stress to equal the weight of the car plus a load more (5G)or something like that. In other words it could be cast in iron or made from billet aluminium.

That reminds me, I must remove my stainless steel wishbones because I know they are crap even if they do look pretty

[B1 ECC]

Thanks for the information, it's input like this that helps current owners who track cars regularly, to be aware of potential problems.Good news, that it was "only " a 60mph corner and you came out-- the other end !!!

[DUBLE PUMPER]

Hi fluxen. Interesting camber and toe in set up bet it doesnt drive very well!!!
Ive got a99 sport and have just had a front lower wishbone break under very heavy braking. Slowing for LA Source at Spa Francorchamp The leading tube has got a dead clean break in it and the trailing tube has been ripped apart so i guess the leading tube went first. Any way it dropped on the wheel luckily so I went straight on up the run off road so the motors not been damaged.
They dont go on the trailer very easy with the front splitter on the ground do they!
Talked to the factory who reckons that the addition of antiroll bars has stressed it up too much.
So B1ecc and me are going to get some new lower wishbones made out of 14g tube instead of the 16g.
The latest front wishbone is a different design to ours and looks a little stronger so they are going to make them to that design. If the price is right of course.
Am seriously considering new uprights after your event.
Is there signs of corrosion i can see where the steel insert is sitting in the casting? cos if it is that could be a reason for the fracture if the steel has been slowly growing in the ally upright!
Ive done about 9k miles mostly on track days and have recently put Dunlop Formula Rs on it and they grip like glue when they get warm. Looks like a race tyre on yours ?
Wont post the pics cos this is really slow old thing and the download time is huge

[fluxen]

DUBLE PUMPER said:

Hi fluxen. Interesting camber and toe in set up bet it doesnt drive very well!!!

I find that the 6" of toe out in front really helps my braking stability, actually

I'm interested in your lower arms, and appreciate you mentioning the break. Are you having these made yourself, I guess, or is the factory making them for you? After this experience I'm definitely going through the suspension and replacing several parts, necessary or not. You can't expect this stuff to last forever I guess

[fluxen]

Video of the failure is kind of interesting. This is 6MB, of the whole lap leading up to and including the break, to give an idea of the kerbs on this track. You can hear and see something's wrong in the braking zone just before the part collapses: http://wurthmotorsports.com/videos/BW_failure_web.wmv

[DUBLE PUMPER]

Hi fluxen
The factory dont seem to interested in making specials ,understandably ,so we are talking to a specialist in Bolton (Ex Chevron factory men) with a view to making the lowers for us.
I will probably fit standard factory units on the top.
They are also looking at modifying the top one to incorporate a sleeve nut to enable infinet adjustment of the camber instead of the full turn of the top joint which equates to about 3/4 degree. It also means you can adjust it without any dismantling. If you or any one else is interested in them let me know and i will give you more info as it becomes available.

[fluxen]

DUBLE PUMPER said:

Is there signs of corrosion i can see where the steel insert is sitting in the casting? cos if it is that could be a reason for the fracture if the steel has been slowly growing in the ally upright! Ive done about 9k miles mostly on track days and have recently put Dunlop Formula Rs on it and they grip like glue when they get warm. Looks like a race tyre on yours ? Wont post the pics cos this is really slow old thing and the download time is huge

Sorry, missed your questions before. There is some evidence of corrosion in the area, though how much the steel may have expanded I can't say as I don't know the stock spec. Directly opposite the wheel there is a crack that was obviously there for a while before this event, but never spotted. I'll try to get a picture so you can see what I'm talking about, but I'd check your parts for fractures.

The tires I'm using are the stickiest tires available in the US as a "Street Legal" tire, so as sticky as you can get short of full slicks. They're much stickier than, for instance, A032R's, and slightly stickier than Kumho Victoracers or Ecsta V700's, if you're familiar with them. We dont' get Dunlop Formula R's here, so I can't give you a comparison.

I can't tell you how much track time these uprights had on them, but it's a hell of a lot, it seems. These are the orginal uprights, and james, the previous owner, tracked the car extensively before I bought it, though with the less grippy A032R's on it.

[fluxen]

DUBLE PUMPER said:

If you or any one else is interested in them let me know and i will give you more info as it becomes available.

I am very interested, so do let me know if you get the project off the ground. you can email me at [e-mail] if you like. It would seem at the moment the A-arms are not going to be an issue for me, as I've got no sway bars on the car, though I've considered the possbility. I may simply go the higher spring-rate route instead, however.

[B1 ECC]

Great Video, car looked really quick, what track was it? Will keep you informed Re: mods!!

[Boosted Ls1]

My money would be on fatigue. I wonder if it's a heat treated item? Probably is.

[B1 ECC]

Tell us more!!

[fluxen]

Yep, my money's on fatigue as well, given the crack opposite the tire that showed evidence of corrosion. The odd thing is that the part would then break in a different spot. Oh, and yes, the uprights are heat treated, at least the new GTR uprights are.

That track is Buttonwillow, a club track around here, in California www.buttonwillowraceway.com/

[turbospud]

did earlier nobles not suffer from the these failures and is it the same component

[DUBLE PUMPER]

TURBOSPUD
Do you know any more about these Noble failures

[turbospud]

magazine road test evo or something like that testing it with others,porche etc had it with road use,dont know if it was the same bit that broke though

[gdr]

Think it was Autocar - seem to remember the problem was not casting but a wrong steering ball joint part - too short a thread so nylock not engaged, unscrewed and fell out.