Please do not adjust your...
Please do not adjust your set, this is a Dirt Late Model running on asphalt. We reconfigured the car and mounted asphalt tires in preparation for an upcoming series race for Dirt Late Model cars on asphalt. Read how we did it.
We have been getting our Dirt Late Model car dialed in at dirt tracks such as North Florida Speedway in Lake City, Florida, and Ocala (FL) Speedway, and we have been getting faster. Then up comes a special promotion by Charlotte County Motorsports Park for a race on its asphalt surface especially for Dirt Late Model cars as a part of the United Dirt Late Model Challenge Series. The race date was August 16th. To say we were excited about the prospects would be an understatement.
Charlotte County is about an hour south of our home base in Tampa, Florida, and is run by and promoted by Bobby Diehl. The sanction for the race is under the UDLMCS banner, and the track offered a test day at Charlotte County on July 8th. This gave us a perfect opportunity to introduce our driver, Bobby Clark, to asphalt racing.
Preparing the car was different, but not so difficult for me. I started out with this whole racing thing on asphalt, and I know these cars well enough to be able to arrange things to work in that environment. The cars were to run on Goodyear asphalt tires that were left over from the Hooters Pro Cup Series when that company supplied their tires. These were very good tires, although they had been in storage for several years. We picked up two sets.
Can you believe it? Editor...
Can you believe it? Editor Rob got busy at the track and actually got his Mechanix Wear gloves dirty. We were hard on him most of the time in good humor, but he really helped out.
Our chassis design has the swing arm rear suspension where the coilovers are mounted wide and straight up and onto the trailing arms. This gives us a wide spring base and helps control roll in the rear while presenting a motion ratio for the coilovers that we would have to design around. We had already mostly eliminated the rear steer in this car, and mounted the Panhard bar on the right side of the chassis. So, it was already close to an asphalt car in that respect.
At the shop, Bobby had installed the springs we chose, reset the front cambers to 4 degrees negative on the right front and 3 1/2 degrees of positive at the left front. We toed the front wheels before leaving for the track to 1/8-inch out versus the 1/2-inch out we normally used on dirt.
We did not yet have the tires, so scaling the car was left for after we mounted the asphalt tires due to the difference in stagger between the dirt and asphalt tires. Aero Wheels set us up with two sets of steel, 12-inch wide wheels that we could use. The series recommended that we use wider wheels than the standard 10-inch wheels that are commonly used with these tires.
Our first runs were on old...
Our first runs were on old American Racer tires that were loaned to us. This gave Bobby a chance to feel out the track without too many expectations. The smaller diameter of these tires vs. our dirt tires looked weird.
We needed to move weight around in the car to a more efficient distribution for running the blacktop. So, we ended up moving most of the lead to the front, to the left, and low. This gave us more left side weight (there was no minimum left side weight rule) and a more even front to rear percent, as well as a lower center of gravity. We ended up with 50.4 percent rear, 56 percent left side, and 53.5 percent cross weight by design.
Bobby also reset the Integra shocks to a more standard asphalt setting, putting the compression and rebound for the front shocks at mid-range, and then taking a couple of clicks out of the compression and adding a couple clicks to the rebound side. In the rear we left the left rear at mid-range for compression and reduced the rebound setting a couple of clicks. We increased the right rear compression a couple of clicks and left the rebound there at mid-range.