by Bobby Kimbrough on April 8, 2011
Dirt Modifieds are one of the most popular classes in weekly dirt track racing series, largely due to the relatively low expense. Many drivers move into this class after a season or two in the bomber stock classes as a stepping stone to dirt late models or sprint cars. Other racers either move into or begin their racing career in dirt modifieds with no intention of racing in another class for the rest of their career.
What attracts most of these weekly racers to the dirt modified classes is not only the affordability but the fact that these cars generate more power than the tires can handle. A driver must master car control in order to do well in dirt modified racing.
One of the most prolific dirt modified racers, Rex Merritt, has spent over 30 years in racing, many of them in dirt modifieds. Merritt was instrumental in helping develop several of the dirt modified chassis manufactured by Dirt Works Race Cars over the years. With over 500 career feature wins and over 36 track championships, Merritt has proven that he knows what it takes to wheel a modified. We talked to Rex about dirt track modified driving techniques that can improve on track performance.
"Don’t worry about looking cool, worry about getting around the track faster than the other racers."
First And Foremost
“I don’t know why, but anytime you put ‘race’ in front of the word ‘car’, people think you have to drive differently,” says Merritt. “Pulling the front wheels off the ground with your feet way up in the air or hanging the back end of the car way out is a lot of fun and you get the sensation that you’re flying but in reality you’re a half a second slower. If you watch the guys that consistently win or do well, guys like Scott Bloomquist or Billy Moyer, they keep their cars on the ground and pretty straight.”
According to Merritt, the biggest thing to initially overcome is the desire to “look cool on the track.” He stresses that, “Really being cool is doing the things that make you faster and finish higher in the field. Don’t worry about looking cool, worry about getting around the track faster than the other racers.”
How To Drive A Loose Or Tight Dirt Modified Car
There are those days when you belt-in and the car is absolutely perfect on the track, and then there are those days when the car is just a little off. In either of those cases, you can still drive the line with some degree of comfort. What happens when you jump in for hot laps and the car’s setup is wildly off? Merritt offered a few pointers on what what to look for.
"Don’t worry about racing against the cushion or getting into the moisture on the bottom. Drive where the track is the fastest."
According to Merritt, “The biggest piece of advice I can offer dirt track drivers is to throw out the idea of racing against other cars and start racing against the track. Don’t worry about racing against the cushion or getting into the moisture on the bottom. Drive where the track is the fastest.”
Merritt continued by saying, “The very first thing you need to look at is where the brake bias is. Many times the chassis builder hasn’t taken the time to set up the brake bias properly. If you can dial in the brake bias to full rear brake and you still have front brake in the car, it’s not set up correctly. This can leave you with a car that feels tight and not matter what other changes you make, from shocks to springs, the car will still be tight in the corner. Most brake bias adjusters have between 13 and 16 turns from stop to stop. Anytime I get into a racecar that I don’t know anything about, I’ll crank it all the way to the rear brake and come off the rear about three turns. That’s where I’ll start off for the hot laps and as the track gets slicker, I’ll dial in more front brake.”
Tire Stagger
Tire stagger is important in Modifieds. Even with a spec racing tire, Merritt explained how he gets tire stagger in the IMCA Modified spec tire:
“I may start the year with eight new tires. I fill them all up to 10 psi air pressure and measure the tire. Then I fill them up to 20 psi and measure them again. The ones that are naturally larger, I’ll take them up to 30-35 psi and lay them in the sun. This helps them stretch a little.
The smaller diameter tires I’ll take all the air out of the tires until it’s time to roll the car. This helps keep the diameter smaller and that’s where you can get your stagger. You can get 2 inches to 2 1/2 inches of tire stagger using this method. You have to keep air out of your smaller tires as much as possible until they have gone through about three heat cycles. That means as soon as you come off the track from hot laps, you put a jack under the car and let the air out of the left rear. Once you have three heat cycles on that tire, the diameter is pretty much locked in.”
Tire stagger will help the car corner and can take an extremely tight car and make it drivable. This is one place in chassis setup where Merritt claims, “You can miss it by an inch,” if you aren’t keeping track of your tire stagger.
Tire Offsets
Merritt also explained that wheel offsets can make a huge difference in fine tuning the chassis which will allow the driver to find a good racing line on the track. “If your car is really tight or really loose during hot laps, you have to take a look at the things that are going to make the biggest difference. Wheel offsets are very important. You can change a wheel on the car without disturbing the scaling that you’ve done at the garage.
“Merritt illustrated the point by telling us what he has seen at various tracks over the years, “Too many times we see guys go out on the track for hot laps when the track is muddy, come off the track and dial in 10 rounds on the weight jack. Then they go out and run a heat race when the track is tacky. When they come off they take the 10 rounds back out and dial in 10 rounds somewhere else. By feature race time, these guys have no clue where the weight and balance of the car is.”
"Having a spotter watch the driver's hands can tell you everything you need to know," says Merritt.
Merritt explained the changes that you can make using wheel offsets, “If you find yourself with an extremely tight car during hot laps, you can run less offset in the right front or you can move the left front or right rear out.” Merritt explained that it helps to have a set of eyes watch the car on the track to verify what the driver is feeling. “Your spotter can watch the driver’s hands on the corner entry and it will pretty much tell him everything.”
Merritt continued by saying, “If the problem is tight on entry, you can move the right front in to help the car pivot better. If the track is a flatter track with minimal banking, I like to move the left front out which will also help the car turn better.” If your car is wicked loose, Merritt says you do the reverse. “If you are making changes with tire stagger and wheel offsets, you’re never messing with the true balance of the racecar. “Key to success is making any changes for the track conditions you expect to see at the later stages of the feature race.
Rex Merritt’s Annual Driving School
In addition to the handful of tips Rex offered our readers here, Merritt holds an annual class at Lucas Oil Speedway in Missouri. The class is a two day event with day one spent in the classroom and day two on the track. Topics cover a full range of categories from front suspension to rear suspension and everything in between. If you’ve ever wanted to know about ackerman steering, brake bias, how to set up your four link or ballast placement, Rex’s classroom training will cover that and more. For the track, Rex covers how to drive a loose or tight car, how to deal with a heavy or slick track and how to out think your competition. There’s really no substitute for the one on one instruction that you will get at Merritt’s driving school. Their is a reason why so many modified drivers look to Merritt for setup and driving advice. With over 500 career wins, he truly is one of America’s most talented modified drivers of all time.
If you want more information about driving a modified on dirt or asphalt, Rex is holding his annual driving class at Lucas Oil Speedway in Wheatland, Missouri. Reservations can be made by calling the Lucas Oil Speedway office at 417-282-5984 or emailing [email protected].
