Cowl Shake
Thread Starter
TECH Fanatic
Joined: Jun 2002
Posts: 1,979
Likes: 3
From: Upstate NY
Re: Cowl Shake There's probably no good news. Converts made from unitbody cars designed as coupes suffer greatly from lack of structure. Removing the roof takes out much of the bending resistance, and lots of the torsional resistance.
Some cars are designed initially to be converts, and then the coupe roof is added, but they are few. The C5 Vette is tremendously torsionally rigid as a hardtop (70,000 miles and no shake or rattles on ours), and still very good as a roadster. The targa roof comes off, so the structure was put into the frame and A-pillar, which is much like a roll bar. Same for the b-pillar.
A 6 or 8-point roll cage would help tremendously if done right, but there's not much else that will, IMO.
My $.02
Some cars are designed initially to be converts, and then the coupe roof is added, but they are few. The C5 Vette is tremendously torsionally rigid as a hardtop (70,000 miles and no shake or rattles on ours), and still very good as a roadster. The targa roof comes off, so the structure was put into the frame and A-pillar, which is much like a roll bar. Same for the b-pillar.
A 6 or 8-point roll cage would help tremendously if done right, but there's not much else that will, IMO.
My $.02
On The Tree
Joined: Jul 2002
Posts: 141
Likes: 0
From: Center Grove
Cowl Shake I have a Convertible Z and I am trying to get rid of the cowl shake (if possible). I installed a STB, which did nothing for the cowl shake, I did notice better turn-in. I have a coupe Z also, which is why I really notice the cowl shake. The two cars are completely different handling cars. The convertible came with K-member supports and a larger transmission brace. Any help would be appreciated.
On The Tree
Joined: Jul 2002
Posts: 141
Likes: 0
From: Center Grove
Re: Cowl Shake Which SFC's fit on the verts, I have two Camaro's and the floor pans are smaller on the vert or the door sills are larger, I know because the floor mats I had in the coupe wont fit right in the vert, They are too big. Thanks for the reply
TECH Addict
Joined: Nov 2001
Posts: 2,662
Likes: 1
From: LaConner WA
Re: Cowl Shake there is probably not alot you can do without extensive custom bracing which will add alot of weight. Double diamonds are what I'd put on there and call it good. They won't cure it, but they will help out.
Re: Cowl Shake Definitely do SFC's as first mod. My car has the BMR tubulars made for the vert. On my car they do stiffen it up substantially.
I didn't see the larger tran support you mention but mine has the 4 rods that attach to the k-member. I have to believe that a 6 point would stiffen it up tremendously, but unless you're going to compete with it might be too much of a comprimise.
As nice as the F-bodys look their construction and materials leave allot to be desired - thank God they had the wisdom to put a killer engine in them <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I didn't see the larger tran support you mention but mine has the 4 rods that attach to the k-member. I have to believe that a 6 point would stiffen it up tremendously, but unless you're going to compete with it might be too much of a comprimise.
As nice as the F-bodys look their construction and materials leave allot to be desired - thank God they had the wisdom to put a killer engine in them <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
