Chassis Stiffness - Coupe vs. Hardtop
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Cruising
Joined: Jun 2002
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From: NY
Chassis Stiffness - Coupe vs. Hardtop
I realize that the hardtop is the best choice for performance, but I really like the looks of the coupe. Can anything be done to make the coupe as stiff as the hardtop? Thanks
Melting Slicks
Joined: Apr 2001
Posts: 2,277
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From: Hoboken NJ
Re: Chassis Stiffness - Coupe vs. Hardtop (silver386)
im pretty sure the coupe is pretty stiff to begin with. If you keep the roof on im sure you arent going to notice the difference until you get on a track.
Team Owner
Joined: Feb 2000
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From: Texas
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St. Jude Donor '03 thru '10, '17
Re: Chassis Stiffness - Coupe vs. Hardtop (silver386)
I love my FRC but the coupe is very stiff too. All C5's are rock solid. If you like the coupe then buy one and fugetaboudit.
Team Owner
Joined: Sep 2001
Posts: 23,283
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From: Lake Elsinore, CA
Re: Chassis Stiffness - Coupe vs. Hardtop (silver386)
I was helping another forum member lower his coupe a couple of weeks ago. He lifted the car with a jack from the right front jacking point with a puck. When I looked underneath, three wheels were off the ground with the left rear as the only point of contact. :eek:
That's what I cal a stiff chassis. :yesnod:
That's what I cal a stiff chassis. :yesnod:
Melting Slicks
Joined: Jul 2000
Posts: 2,483
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From: Wilmington DE
Re: Chassis Stiffness - Coupe vs. Hardtop (silver386)
silver386:
You're right, the Hardtop has the stiffest chassis of the 3 models. This is because the hardtop has the cross brace (just as the convertable does) at the front of the trunk opening, and it also has the overhead roof bow bar that attaches to the frame (just as the Coupe does), AND of course it has the hard top which stiffens the roof of the chassis more that the coupe or convertable.
I saw somewhere that you can buy a brace for the coupe that installs in the roof, which braces it from the windshield back to the overhead bow bar area. I'm not sure if it can be installed with or without the removable top(s) being in or out. This brace should stiffen up the chassis some.
Hope this helps. :cool:
You're right, the Hardtop has the stiffest chassis of the 3 models. This is because the hardtop has the cross brace (just as the convertable does) at the front of the trunk opening, and it also has the overhead roof bow bar that attaches to the frame (just as the Coupe does), AND of course it has the hard top which stiffens the roof of the chassis more that the coupe or convertable.
I saw somewhere that you can buy a brace for the coupe that installs in the roof, which braces it from the windshield back to the overhead bow bar area. I'm not sure if it can be installed with or without the removable top(s) being in or out. This brace should stiffen up the chassis some.
Hope this helps. :cool:
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Safety Car
Joined: Sep 2001
Posts: 4,411
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From: Wilmington NC
Re: Chassis Stiffness - Coupe vs. Hardtop (silver386)
I realize that the hardtop is the best choice for performance, but I really like the looks of the coupe. Can anything be done to make the coupe as stiff as the hardtop? Thanks
I got mine at:
http://www.r-dracing.com/
Le Mans Master
Joined: Sep 2000
Posts: 6,976
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From: Clouds Over California
Re: Chassis Stiffness - Coupe vs. Hardtop (silver386)
I wouldn't say it is the best choice in performance. It was the best choice when GM was trying to remove weight from the car. The elimination of the rear hatch glass saved 100lbs! The solid section might make it a little stiffer but I think it is negligible. It would come down to the driver on the track in any case. The cars are built as if verts, tops are added. I think the fastest C5 speed is Ligenfelter's TT650 Yellow Coupe! It depends on what you mean by performance. The only other C5 I know of in the 9's that is not a coupe is SW's FRC old car and it was High 9's. It would be interesting to see is how close the Verts and Coupes would be if GM included the same motor and suspension as the Z06. I bet the difference would come down to the driver.
Safety Car
Joined: Sep 2001
Posts: 4,411
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From: Wilmington NC
Re: Chassis Stiffness - Coupe vs. Hardtop (silver386)
Hey, thanks for your help guys. It's good to know theres not much difference between the two.
Check out:
http://www.idavette.net/hib/99hdtp.htm
Burning Brakes
Joined: Oct 2000
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From: Seattle suburb wa
Re: Chassis Stiffness - Coupe vs. Hardtop (Shinobi's97)
..might make it a little stiffer but I think it is negligible. It would come down to the driver on the track in any case.
Melting Slicks
Joined: Jan 2000
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From: Wichita KS
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Re: Chassis Stiffness - Coupe vs. Hardtop (Shinobi's97)
Quote from Hib Halverson :cheers:
The Hardtop's underbody structure is the stiffest of all C5s. It has both the Coupe's "top bow" and the extra crossbar behind the seats, characteristic of the Convertible. Its exterior bodywork behind the windshield and above the belt line is bolted to the windshield header and is bolted and adhesively bonded to the rear deck. The underbody structure, the hard top and the lack of the big hole in the back for the hatch make the Hardtop about 12% stiffer in torsion and bending than the Coupe with its roof in place. Additionally, though the removal of the coupe's heavy hatch glass and lighter top structure, the Hardtop's curb weight is 80 pounds less than the lightest Coupe.
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From: Indianapolis Indiana
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Re: Chassis Stiffness - Coupe vs. Hardtop (Flyin'Brian)
LPE probably chose the coupe for top speed testing since it has the lowest coefficient of drag among the three body styles, which is huge at high speeds. On the other hand, it is the only trim that doesn't have the extra bracing, so it's a bit less stiff for autocross, etc (although the bracing is on the vert so that is stiff enough to compare with the coupe in cornering.) All three trims have their trade-off since I personally dislike the look of the hardtops and their lack of removable top. If you can handle their looks, then go for the hardtop. :yesnod:
Le Mans Master
Joined: Sep 2000
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From: Clouds Over California
Re: Chassis Stiffness - Coupe vs. Hardtop (BQuicksilver)
Yeah I guess GM chose the Coupe look vs. the FRC because it looked better on the C5R's too. Have not seen a Hardtop yet. You hardtop guys sure come to the defense quick. Relax your cars are cool. :cheers:
Safety Car
Joined: Sep 2001
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From: Wilmington NC
Re: Chassis Stiffness - Coupe vs. Hardtop (Shinobi's97)
Yeah I guess GM chose the Coupe look vs. the FRC because it looked better on the C5R's too. Have not seen a Hardtop yet. You hardtop guys sure come to the defense quick. Relax your cars are cool. :cheers:
You are barking up the wrong tree. Try better aerodynamics.
[Modified by Richin Chicago, 8:45 PM 6/10/2002]
Le Mans Master
Joined: Sep 2000
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From: Clouds Over California
Re: Chassis Stiffness - Coupe vs. Hardtop (Richin Chicago)
Talkin about the look fewl! Your not going to bust a tear on me are you. PAB!
PS
I love your FRC and you are right about everything. Peace man. You must be right about everything and your probabaly a really fast driver in your car too. From now on when I see you post something I will know better than to challenge your supreme knowledge of your super rigid hardtop. Maybe you can come down and race me at a track or 1/4 mile drag and show me how it helps you.
[Modified by Shinobi's97, 8:47 PM 6/10/2002]
[Modified by Shinobi's97, 9:02 AM 6/11/2002]
PS
I love your FRC and you are right about everything. Peace man. You must be right about everything and your probabaly a really fast driver in your car too. From now on when I see you post something I will know better than to challenge your supreme knowledge of your super rigid hardtop. Maybe you can come down and race me at a track or 1/4 mile drag and show me how it helps you.
[Modified by Shinobi's97, 8:47 PM 6/10/2002]
[Modified by Shinobi's97, 9:02 AM 6/11/2002]
