One of our three project cars...
One of our three project cars this year is a Dirt Late Model Saturday night special. The car is owned by Bobby Clark and was raced mostly at East Bay Raceway Park located in Tampa, Florida. We will be evaluating, testing, and setting up this car throughout the 2008 season.
For some time now, we have wanted to have a Dirt Late Model project car, but the right situation hasn't come along-until now. We have a team in Dream Team Motorsports that is very typical compared to probably 90 percent of the teams in the US who run this division. This team is fairly low budget, it loves to race on dirt, and is struggling to redesign and set up its car. It desperately wants success in whatever form it may take, just like most of you.
So, we have taken on the task of helping Bobby Clark with his program this season. We will be evaluating, redesigning, and setting up the car for races at East Bay and Ocala as well as the regional United Dirt Late Model Challenge Series, a 15 race touring series visiting nine tracks in three states-Florida, Alabama, and Georgia. The car was originally a 2002 CJ Rayburn swing arm car that had been modified to a four-bar car. We intend to again modify a recent conversion back to a swing arm car that more closely resembles the original Rayburn design, but not exactly.
Our work starts with the front...
Our work starts with the front end. We did an evaluation of the front geometry including the moment center, camber change, and steering. We had to make some alterations to the upper mounts, the lower control arm angles, and the upper arm lengths in order to design a MC that was more efficient.
This is a year long project and we will be reporting on our work on the car, as well as the results of testing and racing. We have no unrealistic expectations, just a desire to put together a program that will be consistent and that is well thought out. If you can learn something from all of this, then we will have done our jobs.
The evaluation process will involve a review of the entire chassis for structural integrity, safety, design, and setup possibilities. Late in the season last year, the car was involved in a crash and contacted the wall hard on the driver's side. Several parts of the chassis were bent and these will be removed and replaced.
We will also be looking at previous work done on the car to determine if the welds and other connections are of a suitable quality. We do know that the rear suspension was altered before Bobby owned the car and made into a four-bar suspension. He wants to change the car back to a swing arm suspension and in doing that, we can design some extra adjustment parameters into our new rear suspension.
As we preach constantly, we are doing an evaluation of the moment center location, the rearend alignment, rear steer, front Ackermann effect, weight distribution, and rear traction control devices. We will use many of the important items previously presented in the pages of Circle Track as the basis for the evaluation of this car in order to improve the performance of the total package.
Note the location of the coilover...
Note the location of the coilover mounting point. There are two mounting holes designed into the swing arm. We had to use the front hole in order to have sufficient clearance for the shock/spring. This reduced our motion ratio considerably. Now, the car "feels" a spring rate of 40 percent of the actual installed spring rate on the left and 36 percent on the right side. In order to simulate a 200 pound spring that would be mounted to a clamp on the axle tube would require a 500 pound spring on the left and a 550 pound spring on the right side. For this reason, most teams run too soft on springs for a swing arm car.
We will be installing new design components from many manufacturers for evaluation. Bobby is in the process of installing new body panels, we are having the engine gone over and refreshed, and we are installing a new drivetrain and rearend along with new wheels and other components.
The nice thing about this car is that in its present condition, it is far removed from a production Rayburn, or any other manufacturer for that matter, and this gives us freedom to do what we want with no disrespect to any car builder. Even the builders can look at what we are doing and make notes. We're not saying everyone will agree with all we do, but they will know exactly why we are doing it and then let the chips fall where they may.
Our overall design goal is to build a car that is correct for front suspension geometry, and that will be adjustable in a certain range in order to provide a more balanced setup. The new front geometry design will help make the car turn well through the middle, and the balance will make the car both fast and consistent.
We measured the front end already and made a few changes. Take note that what we did might and might not work with your car, even if it is a Rayburn car, due to the fact that we could not determine if the spindles or control arms were the same as the ones that came on the original car. So, we are not saying this chassis is as CJ would have released it new. We are just taking what we have and modifying it to work.