Torsional Chassis Rigidity
Thread Starter
Drifting
Joined: Feb 2006
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Torsional Chassis Rigidity
What exactly is the benefit of having a very rigid chassis. I know it helps improve handling and reduces flex in the chassis. Does this just help keep the car planted and stable? Hopefully experts can chime in with the engineering perspective and why improvements in stiffness are beneficial. Can you ever have too rigid a chassis?
This is an interesting topic for me not only because of the debate surrounding the targa Z06 Al frame. How do we improve chassis rigidity with our cars, the C6 and C6 Z06. I'd like to know some of the improvements we can make, from mild to extreme. The first one i've learned of is the use of a chassis tunnel plate. Which i'll be purchasing from elite engineering. I've also heard of using roll bars. How would you go about installing a rollbar on the Z06, bolt? Also, how expensive would it be to make the base car a fixed roof (just curious) and how much of an improvement on the chassis would it be? Also, does anyone know what sub-frame connectors are? Thanks in advance.
This is an interesting topic for me not only because of the debate surrounding the targa Z06 Al frame. How do we improve chassis rigidity with our cars, the C6 and C6 Z06. I'd like to know some of the improvements we can make, from mild to extreme. The first one i've learned of is the use of a chassis tunnel plate. Which i'll be purchasing from elite engineering. I've also heard of using roll bars. How would you go about installing a rollbar on the Z06, bolt? Also, how expensive would it be to make the base car a fixed roof (just curious) and how much of an improvement on the chassis would it be? Also, does anyone know what sub-frame connectors are? Thanks in advance.
Race Director
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In the early days of automobiles, frame flex was actually an intentional part of the suspension, in some cars it was the suspension. The cars were often called Flexi-Flyers. But that's changed today. Now the ideal would be an infinitely stiff chassis, so that the suspension does all of the suspension work while the frame just provides a rigid base. Eliminating frame flex is good for the body, eliminating creaks and groans, and it is good for the suspension engineer, who then has complete control over the handling elements of the car as his exclusive domain.
Team Owner
Joined: Feb 2001
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From: Short Hills, NJ
Originally Posted by Tavarez
Also, does anyone know what sub-frame connectors are?
This generally does not apply to Corvettes though.
Melting Slicks
Joined: Oct 2004
Posts: 2,340
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From: Kernersville NC
When you see a NASCAR 'Show Car' on display at the local WalMart or tire dealer it's usually a chassis that is 'worn out' and flexes more now than it did when it was built. Flex is not good these days, especially in race cars. Good question.
Team Owner
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Originally Posted by shopdog
In the early days of automobiles, frame flex was actually an intentional part of the suspension, in some cars it was the suspension. The cars were often called Flexi-Flyers. But that's changed today. Now the ideal would be an infinitely stiff chassis, so that the suspension does all of the suspension work while the frame just provides a rigid base. Eliminating frame flex is good for the body, eliminating creaks and groans, and it is good for the suspension engineer, who then has complete control over the handling elements of the car as his exclusive domain.
Perfect explanation!
Team Owner
Joined: Oct 2001
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Originally Posted by Tavarez
What kind of mods can be done to improve this? Besides the chassis tunnel plate.
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Drifting
Joined: Dec 2005
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From: SoCal
Originally Posted by shopdog
In the early days of automobiles, frame flex was actually an intentional part of the suspension, in some cars it was the suspension. The cars were often called Flexi-Flyers. But that's changed today. Now the ideal would be an infinitely stiff chassis, so that the suspension does all of the suspension work while the frame just provides a rigid base. Eliminating frame flex is good for the body, eliminating creaks and groans, and it is good for the suspension engineer, who then has complete control over the handling elements of the car as his exclusive domain.
I was just schooled.
Thread Starter
Drifting
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Damn I thought the chassis tunnel plate was actually something that was proven. Do race cars use strengthened tunnel plates, I mean you can look into race applications and i'm sure that'll give an answer.
Team Owner
Joined: Oct 2001
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Originally Posted by Tavarez
Damn I thought the chassis tunnel plate was actually something that was proven. Do race cars use strengthened tunnel plates, I mean you can look into race applications and i'm sure that'll give an answer.
Thread Starter
Drifting
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I'll try and see if someone from eliteengineering wants to give a word.
Here's some data regarding temperature on the site but nothing on rigidity yet.
http://www.eliteengineeringusa.com/temperature.html
Here's some data regarding temperature on the site but nothing on rigidity yet.
http://www.eliteengineeringusa.com/temperature.html
Last edited by Tavarez; May 9, 2006 at 12:16 AM.
Drifting
Joined: Jul 2005
Posts: 1,343
Likes: 1
From: CA
Originally Posted by Tavarez
I'll try and see if someone from eliteengineering wants to give a word.
Here's some data regarding temperature on the site but nothing on rigidity yet.
http://www.eliteengineeringusa.com/temperature.html
Here's some data regarding temperature on the site but nothing on rigidity yet.
http://www.eliteengineeringusa.com/temperature.html
Creaking was reduced on my subjective angled/humped driveway test with the steel tunnel plate, but on two other cars I've worked on where the tunnel plates were not added, but the bolts on the stock plate were properly torqued (the factory torquing is random, some bolts are very tight, some very loose) creaking also seems reduced. Hmmm...
Supporting Vendor
Joined: Aug 2003
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From: Beautiful CO
St. jude Donor '14
To be honest, there are so many variables involved, it is really difficult to analyze this with one empirical equation (i.e. shocks, springs, sway-bars). Currently the inner frame rails on the C6 are connected with an 1/8” thin and flexible raw aluminum tunnel plate. Our Tunnel Reinforcement plate is designed to provide a stiffer platform for the suspension. Basically, when the suspension compresses during cornering or driving over bumps the chassis will flex, our Tunnel Plate will limit this flex.
A thicker tunnel plate was first installed in the C5R to improve its stiffness. GM has built the C6 with a stiffer plate than the C5’s sheet metal plate; we have taken this same thought process one step further.
Corvette Fever liked the improved feel so much they featured us in their August 2005 magazine. Lingenfelter, Speed Style & Sound, and LG Motorsports (just to name a few) have all installed them in their race vehicles. Many customer's have told us the car feels like it hugs the road better. "It doesn't flex as much when I approach my steep driveway at an angle".
Trust me, I’m an engineer that likes to see “actual” data. It’s just hard to accurately measure the improved stiffness, but hundreds of satisfied customers cannot be wrong.
A thicker tunnel plate was first installed in the C5R to improve its stiffness. GM has built the C6 with a stiffer plate than the C5’s sheet metal plate; we have taken this same thought process one step further.
Corvette Fever liked the improved feel so much they featured us in their August 2005 magazine. Lingenfelter, Speed Style & Sound, and LG Motorsports (just to name a few) have all installed them in their race vehicles. Many customer's have told us the car feels like it hugs the road better. "It doesn't flex as much when I approach my steep driveway at an angle".
Trust me, I’m an engineer that likes to see “actual” data. It’s just hard to accurately measure the improved stiffness, but hundreds of satisfied customers cannot be wrong.
Last edited by Elite Engineering; May 9, 2006 at 11:36 AM.
Drifting
Joined: Jul 2005
Posts: 1,343
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From: CA
Originally Posted by MAJ Z06
I've talked to one of the C6 Z06 frame engineers, he said all the tunnel plate does is add mass. I have yet to see any numbers proving the tunnel plate really improves chassis stiffness. Just because a creak is gone does not mean that the chassis has been improved, just that a creak is gone.
Clearly GM engineers were trying to achieve something with that tunnel plate. The plate is indeed heavier in the C6 than the C5 (I can compare both side by side), and they specified 36 fasteners for that sucker, which I suspect is not a decision taken lightly when manufacturing efficiency is at stake. (And as many of us have found, they do a damn lousy job of torquing the fasteners.) So I'm not sure I buy the statement that all it adds is mass. If that's true then why did GM add mass to make their plate thicker, and why bother with 36 fasteners?
After a few weeks of testing I got less overall benefit than I hoped for, but I'd still buy one again. I think there is a stiffness difference. Though now that I know I'm living with a hot console either way I'd go for an aluminum one if I were doing it again.
Last edited by Irv; May 9, 2006 at 10:43 PM.
Melting Slicks
Joined: Jan 2005
Posts: 2,263
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From: Houston Texas
Originally Posted by shopdog
In the early days of automobiles, frame flex was actually an intentional part of the suspension, in some cars it was the suspension. The cars were often called Flexi-Flyers. But that's changed today. Now the ideal would be an infinitely stiff chassis, so that the suspension does all of the suspension work while the frame just provides a rigid base. Eliminating frame flex is good for the body, eliminating creaks and groans, and it is good for the suspension engineer, who then has complete control over the handling elements of the car as his exclusive domain.
2nd Gear
Joined: Feb 2018
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[QUOTE=Irv;1555216117]Given the humped & angled driveway test I use I wonder how it would be the case that creaking is reduced but stiffness is not increased...
Clearly GM engineers were trying to achieve something with that tunnel plate. The plate is indeed heavier in the C6 than the C5 (I can compare both side by side), and they specified 36 fasteners for that sucker, which I suspect is not a decision taken lightly when manufacturing efficiency is at stake. (And as many of us have found, they do a damn lousy job of torquing the fasteners.) So I'm not sure I buy the statement that all it adds is mass. If that's true then why did GM add mass to make their plate thicker, and why bother with 36 fasteners?
Heat.
After a few weeks of testing I got less overall benefit than I hoped for, but I'd still buy one again. I think there is a stiffness difference. Though now that I know I'm living with a hot console either way I'd go for an aluminum one if I were doing it again.
Clearly GM engineers were trying to achieve something with that tunnel plate. The plate is indeed heavier in the C6 than the C5 (I can compare both side by side), and they specified 36 fasteners for that sucker, which I suspect is not a decision taken lightly when manufacturing efficiency is at stake. (And as many of us have found, they do a damn lousy job of torquing the fasteners.) So I'm not sure I buy the statement that all it adds is mass. If that's true then why did GM add mass to make their plate thicker, and why bother with 36 fasteners?
Heat.
After a few weeks of testing I got less overall benefit than I hoped for, but I'd still buy one again. I think there is a stiffness difference. Though now that I know I'm living with a hot console either way I'd go for an aluminum one if I were doing it again.