Hey everyone!

I was at the local "pick-it-yourself" a few weeks ago and spotted an '89 RS ragtop. When I spotted the 'vert, I walked over to it...more like ran over to it because 3rd gen 'verts are pretty rare at the local pick-it-yourself yards.LOL!

Anyways, I noticed it was already propped up underneath like all the other cars so I decided to see how weak the frame actually was on these cars. I've always read how weak the unibody frames on our cars are and why SFC's are universally recommended as a "need to do" mod for most 3rd gen's. Well, I walked over to the rear bumper area and started to shake the car up and down. I wanted to see how much flex these 3rd gen 'verts really have.

To my suprise, when I did that the whole back section from the rear edge of the front doors to the back bumper started to wiggle back and forth. I kept on shaking it more and more to the point where the whole back half was twisting back and forth. I couldn't believe my eyes. The car twisted like a wet noodle.

Now, I know most 3rd gens have a relatively weak chassis due to their primitive (late '70's era) unibody construction and how T-top and convertible models would be even worse in this regard, but the amount of twisting I was able get out of this '89 RS 'vert was incredible. It was as if the floorpan was made out of wet cardboard or something. I had no idea that 3rd gen 'verts were this weak in structural integrity.

I looked around for another car to compare it to and spotted a late 90's Pontiac Sunfire convertible parked close to the Camaro. I walked up to Sunfire 'vert and started to shake the back bumper on it to see how much flex that car had compared to the Camaro. Nothing. Zilch. Zero. It was solid as a rock. I couldn't get any flexing and/or twisting from the Sunfire whatsoever. I guess GM finally learned how to design a torsionally stiff convertible unibody chassis.

One thing I have noticed on most late model GM unibody cars, like the J-car Sunfire and 4th gen F-body, is that the rocker sections are HUGE compared to older unibody cars like ours. It's almost like having factory integrated SFC's on these newer models.

 

Were the doors shut and attached correctly? The doors form an intrigal part of the superstructure.

Kevin D.

 

Yeah, the doors were closed when I did this.

However, I'm not sure if those rubber wedge thingies on the back of the front doors were adjusted properly or not, but the doors did open and close properly when I tried them.