Dick rates each and every spring every time one is used. I needed those rates in order to
This year more than 40 teams showed up, coming from all over the country in some cases, to run one more race after their seasons had ended. It's a 200-lap race, so endurance and consistency are important to success. In the end, the race was won by central Florida racer and veteran David Rogers.
Our first test session was conducted two weeks before the race and in attendance was Stephan Nasse who would eventually lead the most laps in the race. Nasse was consistently fast throughout the test, but couldn't match our speed. We'll get more into that later on.
Dick's car that had been run all summer had recently been destroyed when the throttle stuck. Jeff Scofield was the driver and luckily he survived with just a few bruises and would pilot our test car. So, over that past month, Dick built a brand-new car of his own chassis design modeled after a Howe fourth-design front end that was in use around the early 1980s.
I measured the car and looked at the moment center locations and it was something we could work with. It (MC) was a little more left than I'm used to, but I felt that it would work in combination with the stiffer springs we were running. We decided on the spring rates and ran a computer simulation to derive the proper Panhard bar heights and rear spring split to go along with the high front spring rates in order to achieve a balanced setup.
The geometry in the front end is based upon a Howe Fourth-Design front end and was somethi
We ended up with these springs: RF = 1,130; LF = 980; LR = 190; RR = 250 with a 1 1/8-inch diameter medium-rate sway bar with just one turn of pre-load. This would equate to a coilover car (based on our wheel rate translated to an equivalent coilover spring placement) with front spring rates of RF = 536 and LF = 485. Believe it or not, this is how stiff cars used to run. In the old days of the late '70s and early '80s, there were not so many coilover cars. Most cars were based on stock front clips and those used big springs.
When you think about how utterly stiff these springs are, stop to consider that when a car is on bumpstops or in coil-bind, the wheel rate goes to 1,500 to 2,000 ppi or more. So, in reality, we're using about 1/3 the rate of the BBSS setups at mid-turn.
One other thing Dick wanted to try was using the small sway bar. We installed a 1 1/8-inch-diameter bar with medium thickness walls. He felt that we could put pre-load in this bar without making too much of a change in the crossweight that would affect the mid-turn handling. The sway bar can really help with bite off the corners, and Turn 4 at NSS is notoriously loose off.
We checked for Ackermann and reduced it to a minimum to gain about 1/32-inch of toe at mid-turn. We ran 1/8-inch of toe out. We also checked the rearend for square and the right rear tire patch alignment with the right front tire contact patch and both were perfectly aligned.
We went through the entire car and checked for rear alignment, right side alignment, Acker
Dick ran a crossweight that I consider to be in the high range and it ended up at around 57.3, while his left side percent was 57.7. This matched up with his front-to-rear percent. All of the other settings such as the shocks, rear trailing arm angles, caster and cambers, and third link angle were what he had been running.
Two weeks before the event, we tested at NSS. Initially we were fast right out of the trailer, but when pressed, entry and exit issues became apparent. We ran laps in the 17.70s to 17.80s range, which exceeded all other test cars by 0.2 to 0.3s. This was looking good, but we still had a way to go.
Turn entry was a problem and we couldn't get the push out of the car. We made numerous changes that should have made the car loose as a goose, but didn't. So, I made the conclusion that something mechanical was wrong. I learned that Dick had only 1/2-degree of right trailing arm angle in the car with almost 5 degrees of left trailing arm angle. This produced a lot of rear steer that made the car extremely tight.