An interesting experience at the track last night. My car is still down for some small changes, but I went to the track to watch. The fastest street car challenge was running.
A fella had brought a 1968 Chevelle to the track with a BBC and 3 stage NOS system. The stock style suspension components were being used. The Chevelle suspension is very similar, if not exactly the same as the TRs. A lot of TRZ suspension parts in the front and coilover shocks in the rear with adjustable uppers and a disconnected roll bar. A stock 12 bolt rearend housing was being used and he had a bracket at the rear uca mounting point to allow a raised mounting point. The rear tires were nicely tucked into the fenders and with a recent addition of the rear coilovers, he had lowered the riding height in the rear to give the car a level rake look.
After watching him make his first pass, I was interested in checking out his suspension setup. I had met him at a previous track meet and knew he was running the stock style suspension setup. This car was also the one that was used as a suspension example for the El Camino Chevelle that won the 'Drag Race High' challenge. He had since done some changes to the rear suspension though.
He had some major problems on the first pass. As soon as torque was put to the car, the tires would blow away, no matter how far down the track he had progressed.
After taking a quick peek at his rear suspension, he told me he had disconnected the rear roll bar because of his traction problem. That really didn't make much sense to me and I ignored that. I noticed the uca rear mount was in the raised location and that the lca was pointing downward viewing rear to front. The car was lowered that much. I asked him if he had plotted his IC and he replied that he had not. He was obviously at a point in his knowledge of suspension setup that I was at not too long ago.
I made the comment that his IC looked to be short and low, and that he should plot it out. I left it at that and went back to spectating.
His next pass looked the same as the first. Just horrible. I have a soft spot for the 1968 Chevelle. It's what I terrorized the streets with when I was in high school, so I went over to talk with him again. He said that he had changed the uca mounting back to the stock location for the second pass with little change in the way it hooked. I confirmed that for him. I went ahead and mentioned that I thought he had lowered the car too much and that he should raise the ride height until the lca was, at the very least level, if not pointed upward a little viewing from rear to front. I then went back to 'spectator mode'.
His next pass was much better. The tires absolutely hooked on the launch. So well that he momentarily backed out of the throttle, later telling me that he thought the power was down since the engine rpm didn't rise like he expected. That will happen when the tires hook.
The car was still a little loose on the top end where he brought in the other stages, but the improvement was very noticeable. At least, the tires weren't simply blowing away. I went back to his pit where he, along with his helper confirmed that the suspension change did make a difference.
I think they were just as surprised as I was as to how much it did. He was off to a good start in learning about the importance of suspension setup.
By the way, he was running a 10" slick.
