Dirt cars of every form are...
Dirt cars of every form are now using the left front tire more and more. The use of proper front moment center design combined with a more balanced setup keeps the four tires on the track for maximum traction.
"How dare an admitted asphalt guy tell us dirt racers how to setup our cars? Just where does he think he is coming from?" you could ask. I'm sure more than a few dirt racers have said that or a similar expression from time to time. And it's my fault that they might feel that way. I have never fully explained why or told the progression that led me to think the way I think and what my experience working with dirt teams has been. It is spotty at best, but there was a progression, so let me explain.
It was around 1996 that I met a guy named Dewayne Ragland who then worked for Bilstein shocks. He had gotten to know most of the important players in Dirt Late Model racing and was kind enough to show me around the Midwest and introduce me to people, including C.J. Rayburn. I had these crazy ideas about roll/moment center design and setup balance that I thought might as well be applied to dirt cars just like I had applied them to asphalt cars with great success.
I was a complete dummy about any aspect of dirt racing at the time, a condition that I have since found could be a plus when trying to discover something new. I didn't have the restrictions of following in the footsteps of those before me because I didn't know anything about the technology that came before me.
The First Clue
You can substitute a mono-ball...
You can substitute a mono-ball upper or lower ball joint so that you can adjust the height of the ball joints. This changes the angles of the control arms and the location and movement of the moment center. The location of the moment center dictates the efficiency of the front end.
I got a call in mid-1997 from Dewayne and he told me the team he was working with had won a race with a balanced setup. I was pleased and asked what the setup was. "We ran a 400-pound spring on all four corners," he told me. "What?" was my reply. You can't run 400-pound springs on the back of any race car. I didn't then know about the swing arm design on the Rayburn cars and so it was like running 400s up front and 200s in the rear on a four bar car. That made much more sense.
Then in late 1997, Dewayne called me and said he had this dirt guy on the phone and he wanted me to talk to him about some problems he was having. I refused to talk to him because as I told Dewayne, "I don't know squat about dirt cars." He insisted and after a long discussion where I finally agreed, he said, "I've got Billy Moyer here with me." Again I said, no f'ing way, and after another round of arguing he put Billy on the phone.
He told me his car had been very inconsistent from race to race and even in the same event. I asked some basic questions about the car, but remember I was clueless. I asked which side the J-bar was mounted on and of course he said the left side, just like everyone else-dummy. I had found with Asphalt Late Models that when the bar was on the left side of the chassis, the car was inconsistent and I said he might try running it on the other side. How stupid was that?
The angle and length of the...
The angle and length of the control arms determines the location of the front moment center. On our new Dirt Late Model, we see a long left upper control arm. This helps to reduce the upper arm angle and also helps us introduce more positive left tire camber.
Well, the next race was the finale for the '97 season of the Hav-A-Tampa Dirt Late Model Series, the Dixie Shootout, where Billy could clinch the series championship. The stakes were high. I decided to drive up from my home in Ormond Beach, Florida, to see what happened. I was there when the team took the car off the trailer and sure enough, the J-bar was on the right side. This was going to be interesting.
The short version is this: Billy set fast time in qualifying, won the dash for cash, won his heat race, and won the feature-and of course the series championship. I'm not going to sit here and say moving the bar did it, but it sure didn't hurt either. That event told me that maybe there was room for discovery in dirt racing.
The Second Clue
Then in March 1998 Dewayne and I put together a test at Eldora to try running balanced setups. At the test was Kevin Weaver driving our four bar test car and Billy Moyer running his own setups in a Rayburn car. On Kevin's car we ran a pair of 375s on the front and 175s on the rear. All day we were consistently 0.5 second, or more, faster than Moyer who was running the standard stiffer right front and softer right rear springs.
Back then Eldora had a high banked top groove of about 19 degrees and held moisture well. These were ideal conditions to run a setup more like the asphalt setups I was used to. And it worked. We shared the info with Billy and Dewayne helped him set up the Rayburn so that it would be much like Weaver's car for The Dream at Eldora that June. I think we had 375s up front and 350s in the rear. Billy won the race and the $100,000. He also came back and won the World 100 that year with Kevin finishing Second, lapping the entire field up to fourth place.