Did a search here and could not find a post on point. Anyone know the actual torsional rigidity of the crossfire and how it compares to its competitors?

Coming from the 350Z to the crossfire I would say it feels stiffer than the Z but not quite as stiff as the 1991 300ZX HARDTOP I owned.

 

Think I read it had more torsional rigidity than a 911. Can't remember source though, Car and Driver maybe.

 

I found "he foundation for creating a car with responsive sports coupe handling combined with a supple ride is a stiff body shell. Crossfire's all-steel shell boasts exceptionally torsional rigidity (20,140 Nm/deg) and has been specially reinforced to bear the loads and forces generated by the unusually large wheels and tyres." Don't know what it means except STIFF.

 

I read on a Chrysler website, that during the designing of the car, they tuned the chassis to be stiffer that a porches Carrera. I just can't remember how they measured it, I think in MHz too bad I forgot the specs.

 

Torsional rigidity is measured in in.lbs./degree.

And that's where my Crossfire doesn't measure up.

When introduced the Crossfire was touted as one of the stiffest chassis available. And mine felt that way at first.

But about 7 months after delivery it suddenly developed a road noise from the bottom rear of the driver's door. The door started moving around whenever the car hit an irregularity in the road accompanied by creaking noises in the roof above the rear bulkhead. It also started darting to the right when the right front wheel hit a dip or encountered a slippery surface.

Two dealers have made seven attempts to correct this problem without success.

I suspect that the spot welds that attach the body to the frame are failing.

I also suspect that a lot of the complaints about "wind noise" on this forum are the result of road noise caused by the doors coming part way open due to chassis flexing caused by this problem.

 

I don't know about that, I would like to see some proof of your spot welds separating. Got any photos to prove that.

 

I remember reading that the Xfire is stiffer than a 911, but sometimes when I enter an off camber driveway, my car creaks a bit like it is flexing.

 

The coupe is 50.4 Hz and the roadster is 29.9Hz.

 

I remember reading in one of the service manuals that many of the Crossfire's parts are bonded (read: "glued") rather than welded because it distributes the load more evenly. Maybe some of the glue is going soft on you...

 

Maxwell, it would require major disassembly of the car to get photos of the spot welds.

My clue on this was that the car changes shape as the temperature changes. Above 50ºF the driver's door would close normally, below that temperature the driver's window would hang up on the drip rail and at 10ºF the window would overlap the drip rail by about 3/16". On the fifth trip to the dealer for this problem they installed the factory fix and the window doesn't overlap the drip rail any more but you can still tell the temperature by the gap between the window and the drip rail.

Since my problems with the door rattling loose in the frame and popping part way open (with resulting road noise) do not seem to be common to Crossfires I suspect that it is a unique structural failure.

Bobs, if it is a bonded structural failure it would be ironic since I worked for Grumman American which was the first light aircraft manufacturer to offer glued together aluminum aircraft to the general public. Though bond failure would explain some of the problems I've had with the car.

BTW I've been in the engineering business for over thirty years and owned and maintained my own race cars so I like to think I know a little about structures.