C5 Chassis flex
Thread Starter
Racer
Joined: May 2002
Posts: 359
Likes: 0
From: Lloydminster AB
C5 Chassis flex
I was reading the Pop Sci article "King Cobra Talks Hybrids" the other day. In this article they were comparing the flex in the 1962 cobra chassis, 700 lbs per degree of flex, to Carroll Shelby's latest creation, an aluminum honeycomb chassis with a rating of 12 000 lbs per degree of flex. In the GM vette promos they talk about how they have stiffened up the C5 chassis. Does anyone know the flex rating on our chassis? You never know when this bit of trivia will come in handy. :)
Safety Car
Joined: Nov 2000
Posts: 4,419
Likes: 6
From: Arroyo Grande CA
Re: C5 Chassis flex (shaky)
STIFFNESS (Hz = resonant freq.)
C5 convertible = 21 Hz (61.5% stiffer than C4 Conv.)
C5 Hardtop = 23.5 Hz (12% stiffer than C5 Conv)
C5 Hardtop = 80# lighter than C5 Conv.)
I don't remember where I got this info, nor do I know how this converts to lbs per degree of flex.
Hopefully someone with the expertise will chime in on this.
Me too. :lurk:
C5 convertible = 21 Hz (61.5% stiffer than C4 Conv.)
C5 Hardtop = 23.5 Hz (12% stiffer than C5 Conv)
C5 Hardtop = 80# lighter than C5 Conv.)
I don't remember where I got this info, nor do I know how this converts to lbs per degree of flex.
Hopefully someone with the expertise will chime in on this.
I was reading the Pop Sci article "King Cobra Talks Hybrids" the other day. In this article they were comparing the flex in the 1962 cobra chassis, 700 lbs per degree of flex, to Carroll Shelby's latest creation, an aluminum honeycomb chassis with a rating of 12 000 lbs per degree of flex. In the GM vette promos they talk about how they have stiffened up the C5 chassis. Does anyone know the flex rating on our chassis? You never know when this bit of trivia will come in handy. :)
Melting Slicks
Joined: Jan 2001
Posts: 2,635
Likes: 2
From: Aloha, Oregon
Re: C5 Chassis flex (silver386)
all i know is that my coupe is STIFF!! It blows my mind. I inadvertently came across this little test: I had my car up on 4 jackstands a little while back dealing with some exhaust issues. I had 2 stands under the rearend girdle and one on each side of the front end of the car on the jacking point just forward of the doors (behind front tires). I took the front passenger side jack out from under the car so that the car was resting on just 3 jackstands. to my amazement, the front pass tire was still the same distance off the floor and the front driver tire!! the pass door opened and closed like butter. there was NO contortion or body twist i could see. this is one stiff car. all the other cars i've ever owned, including my 91 ZR1, would have flexed severely under these same conditions. I remember being able to hear twisting, creeking and flexing of body panels, doors and hatches when jacking these other cars up. no my C5.
[Modified by rwj383, 11:01 PM 12/21/2002]
[Modified by rwj383, 11:01 PM 12/21/2002]
Thread Starter
Racer
Joined: May 2002
Posts: 359
Likes: 0
From: Lloydminster AB
Re: C5 Chassis flex (rwj383)
I did a bit of searching around and GM doesn't appear to be publishing this type of info. No surprise I guess this type of data would be confidential. What I did find was the techniques used to manufacture the C5 chassis have resulted in 450% improvement in rigidity. The article didn't say what the improvement was compared to though.
Drifting
Joined: May 2002
Posts: 1,607
Likes: 1
From: San Francisco CA
Re: C5 Chassis flex (shaky)
From what I've read they designed the C5 as a convertable first to be sure it didn't have the shakes and rattles of previous convertables. That automatically made the coupe stronger and the hardtop the strongest (no removable roof panel).
Team Owner
Joined: Mar 1999
Posts: 28,753
Likes: 9
From: San Jose/Bear Valley CA
CA Events Coordinator
Re: C5 Chassis flex (shaky)
Want a realtime lesson in chasis stiffness? I had a flat tire on the front right hand side. When I pulled over to the curb I got out to see the tirea had come off the bead of the rim and the rim was suspended in the air. :eek:
vetterdstr :cheers:
vetterdstr :cheers:
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Intermediate
Joined: Aug 2002
Posts: 25
Likes: 0
From: Las Vegas NV
Re: C5 Chassis flex (vetterdstr)
Ford put those numbers in to dazzle people. You can make some people believe anything you want if you throw enough-mean nothing numbers- at them. Just my opinion. Ford has always had a slight inferiority complex when it comes to the Vette and thier pony car.
Team Owner
Joined: Jul 2001
Posts: 21,349
Likes: 986
From: Various places in Southern California.
Re: C5 Chassis flex (vetterdstr)
Want a realtime lesson in chasis stiffness? I had a flat tire on the front right hand side. When I pulled over to the curb I got out to see the tirea had come off the bead of the rim and the rim was suspended in the air. :eek:
Team Owner
Joined: Jul 2001
Posts: 21,349
Likes: 986
From: Various places in Southern California.
Re: C5 Chassis flex (korvettekarl)
Ford put those numbers in to dazzle people. You can make some people believe anything you want if you throw enough-mean nothing numbers- at them. Just my opinion. Ford has always had a slight inferiority complex when it comes to the Vette and thier pony car.
Melting Slicks
Joined: Feb 2002
Posts: 2,450
Likes: 0
From: Kansas City Missouri
Re: C5 Chassis flex (korvettekarl)
Ford put those numbers in to dazzle people. You can make some people believe anything you want if you throw enough-mean nothing numbers- at them. Just my opinion. Ford has always had a slight inferiority complex when it comes to the Vette and thier pony car.
Melting Slicks
Joined: Aug 2000
Posts: 2,112
Likes: 2
From: Sindelfingen Germany
Re: C5 Chassis flex (shaky)
Next time we get a vette we will measure it. The way we do it is called one wheel drop test.
Last time DC had a vette it was mainly for examinating the HUD. Car was gone two weeks later.
The numbers up above in one answer are those for dynamic stiffness. Global static stiffness has to be measured separately and cannot be equated out of that ones.
Frederik
Last time DC had a vette it was mainly for examinating the HUD. Car was gone two weeks later.
The numbers up above in one answer are those for dynamic stiffness. Global static stiffness has to be measured separately and cannot be equated out of that ones.
Frederik
Burning Brakes
Joined: Jun 2002
Posts: 1,055
Likes: 0
From: Troy MI
Re: C5 Chassis flex (C5 Frederik)
I jacked my car up from one side to put a jack stand under, then went to jack the other side up to make it level and noticed that the other rear wheel was off the ground only slightly less than the one which was held by the jack.
I attribute this 100% to downard travel of the front end on the suspension of the oposite side, I am sure that if I had the front jacked the back would have been at the exact same height on both sides.
[Modified by msuc5vette, 11:55 PM 12/23/2002]
I attribute this 100% to downard travel of the front end on the suspension of the oposite side, I am sure that if I had the front jacked the back would have been at the exact same height on both sides.
[Modified by msuc5vette, 11:55 PM 12/23/2002]
Heel & Toe
Joined: Jul 2009
Posts: 24
Likes: 1
How to measure C5 chassis flex
I have an ‘03 Z06 with an 8 point cage. I had been driving it as a 6 point cage for a while (without the 2 forward bars from the A pillar through the firewall to the front of the frame). I noticed when angle parked at a weird curb where the left front wheel was about 4” higher, putting a twist in the frame, I had much difficulty getting my swing-out door bar pin to release. The front of the frame had twisted! Later as I was fabbing the forward bars, I discovered that (with the car just sitting there on the garage floor) turning the wheels full lock to the right, then left, caused some frame twist. Using a 48” carpenter level placed under the front and rear suspension crossmembers, I measured 1/8” gap (@ 48”) difference from wheels left vs right. This is probably due to minor castor change. This is NOT just measuring at the front crossmember, but is measuring the DIFFERENCE between front and rear crossmember levels, ie the TWIST change of the frame.
After welding in the forward bars, I measures NO twist, even at that weird parking spot, no problem getting the pin out. I know the C5 is stiffer than previous Vettes and the frame looks massive, but they do move,,,,,just more than I imagined.
After welding in the forward bars, I measures NO twist, even at that weird parking spot, no problem getting the pin out. I know the C5 is stiffer than previous Vettes and the frame looks massive, but they do move,,,,,just more than I imagined.
