Our Dirt Late Model project car goes to Victory Lane. All of our hard work has paid off wi
The Circle Track Dirt Late Model race car project, otherwise known as Project DLM, started in March 2008 in the garage adjacent to our offices in Tampa, Florida. We joined forces with Bobby Clark, a driver and team owner who had limited experience with driving Dirt Late Model cars. We wanted to build our project with a team that could grow with it. From the very start, we realized that Bobby was just the guy we needed.
He proved that on July 11 at North Florida Speedway in Lake City, Florida, when he won the feature event. Watching the video (online at www.circletrack.com), I saw a more confident and comfortable driver now that he had a few races under his belt, and especially since he had tuned the car to suit his liking, using much of what we write about in Circle Track. Through numerous restarts, he held his ground and used patience and determination to bring in his very first Late Model win.
You can tell when someone is open to learning his craft. Bobby dreamed of driving and winning in a Dirt Late Model from early on in his life. He was so eager to learn that we had to pull back on the reins a bit at times, walking him through the processes at a slower pace so that the details would sink in-and boy did they ever.
I have to say I learned a bunch along with Bobby. Some of the things I wanted on the car just did not work. This is a story about how we tuned our car for performance and Bobby's preferences. We have more work to do for next season, but with the win to boost us, we are well on the way.
The rear links we observed were similar to the original Rayburn, but had some strange angl
Early Development of the Chassis We started out with a 2002 Rayburn chassis that, as you might know, is a Z-link rear suspension in which the bottom link goes forward from the birdcage to the chassis and the upper link goes to the rear. The link ends are adjustable for height to provide more or less rear steer. In our original configuration, we mounted the coilovers to the lower links, making the suspension a swing arm-type, with a motion ratio for the spring rate to wheel rate.
Lift Arm to PullBar The lift arm design that was in the car at that time was replaced by a dual spring third link with double shocks to control rearend wrap-up and rebound. This is a unit that we experimented with at Eldora in 1998 and was used in the winning car for the Dream and the World 100 that year. That track was very high banked at that time, 19 degrees in the upper groove, and had a good amount of bite.
Frontend Geometry Our overall design goal was to build a car that was correct for front suspension geometry and that would be adjustable within a certain range in order to provide a more balanced setup. The new front geometry design we established did help make the car turn well through the middle and the balance we established made the car both fast and consistent.
In the end, we reintroduced rear steer, although with the swing arm design and our right-s
What we did to this chassis might and might not work with your car, even if it's a Rayburn car, due to the fact that we couldn't determine if the spindles or control arms were the same as came on the original car. Bobby bought the car used in 2006. So we aren't saying this chassis is as CJ would have released it new. We modified it to work just like many of you might do.
Reduced Rear Steer Our goals for setup are to provide a more balanced car on tight tracks where the level of traction is high, and also one that will provide more bite on the drier surface tracks. Most tracks we ran were the latter-dry and slick, like you probably encounter.
Along with the spring layout and roll center locations, we proceeded to design less rear steer into this car and a little different weight distribution than what many racers are used to. That would change. We positioned the links off the birdcages to be more level, so when the chassis moved, the ends of the rear axle tube would remain in the same position fore and aft.