RTK Motorsports
04-15-2015, 08:25 AM
I recently purchased a metric street stock and started going through the car, I was a leaf spring guy prior to this, but my car was totaled at the end of the season last year.I weighed the car, here were the results. The fuel was not topped off, I think it took 12 gallons when I topped it off below, so the rear weight would have been slightly higher. Car stats: RF spring 1250, LF spring 1000 RR spring 200, LR Spring 225 RF/RR Tires 255/60/15, LR Tire 245/60/15, LF Tire 235/60/15 All 4 corners have pro shocks Ride heights: LF 6.75 RF 7.00 LR 8.00 RR 8.25 Weights: LF: 940 RF: 707 LR: 898 RR: 731 48.9% Cross, 56.1% left 49.7 rear. 210lbs of lead on left frame rail 20 inches back of rear end To me, the numbers looked wacky and from what little knowledge I have the car would seem to be far from neutral. From research I also felt the rear weight and cross was low. After topping off the fuel and moving weight to the right and over center of the car, here are the numbers. LF: 808 RF: 802 LR: 921 RR: 783 52% Cross, 52.2% left, 51.1 % rear. Specifically to get the car to a 50+% I mounted 110lbs on the right frame rail 20 inches aft of the rear end and 98 lbs above the rear end approximately 10 inches and 8 inches aft of the rear end. This is a bar weight that stretches across the rear width of the car. I went to the races on Saturday night and noticed the car was loose on hot laps, but the track was wet. In the heat race, I entered turns 1/2 with some caution and the car held, in 3/4 just before the center of the corner the car snapped loose without notice. I had a lot of wheel spin exiting corners, I had to work the brake pedal to keep the car in shape the remainder of the night. I am assuming that I flat out just need more rear weight, but I am also wondering if the setup from the previous owner is normal and I just screwed it up. Anyone with tips or knowledge please chime in.