So we finally had nice enough weather to take the Targa top off of my recently purchased '94. Immediately after leaving the driveway and accelerating to the speed limit of 55 mph, we experienced a very distinct and noticeable vibration in the car. Initially it felt like that entire front end was out of balance. When I put the top back on the car later in the day and drove it around, the car seemed normal again. I have done this several times now and without question, the car shakes a lot more with the top off.

Initially, we left the top in our garage. Later on we put the top in the back part of the car behind the front seats....not a very good fit. I think the vibration was worse when the top was not stored in the back of the car.

My opinion is as follows:

1. With the top on, you basically have a 'box beam' structurally and lose some structural integrity upon removal. Makes sense, but does not speak well to the structural integrity of the car.

2. Air flow into the space behind the front seats may also exaggerate the issue. The fact that it appears to be different when the top is stored back there would support this idea. The difference with the top stored in the back of the car is minor enough that I could convince myself that it is psychosomatic (that is a big word for me) more than anything else.

3. Most important. Could it be that the tires are slightly out of balance and removing the top exposes this issue.

As always, feedback welcome.

K.C.

 

The first time I drove my 95 without the top it freaked me out too. I asked a local friend who has one and he said it shouldn't be as bad as I described. There has to be somewhat of an issue there or they would not of made the targa truss bar as seen on page 141 of the corvette central catalog. It reduces body flexing, front end noise and steering wheel vibration. All that... seems to happen when I remove mine. You are not alone but I still take it out and drive it hard.

 

My '93 shook badly with the top out until I had my tires road force balanced. This made a huge improvement. There's still a difference with the top out, but it's just a quirk of the C4 design.

 

Ditto here. I mostly leave it on for that reason. I'm doing inner/outer tie-rods now because I think it's part of the cause. New tires, a wheel balance and alignment couldn't hurt.

On a lighter note, a co-worker of mine went to lunch with me once with the top off (the car...lol). She said she could feel her breasts moving left to right when we were driving....

 

The car was never designed to be a Targa. The C5 was. You need to either use a convertible brace or , chassis stiffner (rear 4 point roll bar) or a roof bar. Otherwise, all it will ever do is **** you off, as it becomes a flexible flyer with roof off.
I use an S/T frame, Camber brace and this Targa Truss. The Targa Truss makes it tighter than with the roof on.
http://www.r-dracing.com/targa-truss.htm

 

 

Thats the deal...where can I get one? It looks better than the one they sell in Corvette Central.

 

It is a AFSB Targa Bar - I happened to pick mine up used here on the forum, but here is the vendor's page:

http://www.prostreetcustoms.net/CorvettePage.html

 

This is the one im looking for. the square tubing looks cheesy to me...MHO.

Where did you find it and how much? Someone told me they were discontinued.

thanks

 

Nevermind.. I see your post/link now. i got excited when i saw it...lol

I love that bar. I've seen it once in person and offered to buy it right then and there but they said it wasn't made anymore. I'm glad to see otherwise...