One of the vagaries of dirt-track racing is the difficulty of getting any quality test laps to try out new products, setups, or even--for that matter--gain some seat time for a new driver. An asphalt track can change by degrees depending on track temperature, whether old rubber has been washed off by rain, etc.. But a dirt track can be Jekyll and Hyde by comparison. A good dirt track requires almost daily preparation just to be groomed for weekly racing events. And even if a track is in top shape and ready to roll, if you are testing in the heat of the day it won't stay that way for very long.
That's part of the problem HHH Racing had run into. Driver Chris Hargett and crew chief Neil Wilson have a car that works well overall, but they've struggled a little nailing down the perfect handling setup. "The car seems like it's almost always too tight," Hargett said. "Little changes don't make much of a difference, but when we make a big change it will go way too loose. I like to drive a loose car, but there are limits. We're just having a little trouble finding that middle ground."
Hargett drives a dirt Late Model he bought used two seasons ago. Last season he won one race and had several top finishes and is eager to improve this year. HHH Racing has been using the same type of brake pads that came on the Stinger chassis when it was purchased in 2000, and Hargett and Wilson felt that the brakes have been a tuning tool they have ignored. Other than adjusting the balance bar, the brakes have been left as a constant while the team worked with the other adjustment options available.
Test & Tune Plan
To lend a hand we asked the experts at Performance Friction to provide some advice and lined up a dirt track to do a little testing. Rock and Mike Gault, the former owner/operators of Cherokee Speedway in Gaffney, S.C., still own a small track behind the speedway that they keep in good condition. Mike has plans to expand the racing surface, install new grandstands and infrastructure and bring in special events in the near future. Right now, though, it was available for our use, so we took advantage of it.
To get a reliable baseline, the night before the test Wilson and Hargett put four new Performance Friction rotors on the existing Wilwood wide-five hubs, then reattached their existing Wilwood Prolite calipers. The 11.25-inch rotors aren't the lightest pieces available, but the engineers at Performance Friction believe that there's a lot more speed to be lost by running warped rotors constantly scrubbing the brake pads than there is by running a little extra rotor weight. The extra beef in the rotors is there to make sure they don't suffer from excessive runout after just a few events--they should spin freely for at least a season's worth of racing at this level.
Brett Gipson, Performance Friction's powersports managing engineer, met us at the track at 10 a.m. and began discussing ideas with Wilson and Hargett on how to attack the test. The pads Hargett had been racing were not high-friction by any means, so Gipson sug-gested going to the other extreme. Install the highest-friction pads available and then allow Hargett to work his way down the scale until he found a setup he could work with. Performance Friction uses a two-digit labeling system for its pads that's slightly intuitive in that the higher numbers generally provide more friction against the disk, but it's not always a simple subject. Some pads start out with little frictional coefficient but continuously grab harder as they build up heat. Others have more grab when cool but are also more consistent, so the pad with less cold friction can actually surpass this pad once both get hot. For a better description of the characteristics of each brake pad Performance Friction offers, see the accompanying sidebar.
Test Conditions & Comment
The day was cloudless and dry with a slight breeze. The temperature was perfect for being outdoors--a mild 70 degrees. Unfortunately, it's also a pretty bad combination of conditions for keeping a clay oval in racing shape. The midday sun and a dry breeze pulled the water out of the track faster than you can say dry slick, and no sooner were we in the meat of our test than we were choking back dust every time the car came by. Rock Gault brought out another truckload of water, but it didn't take long for the track to return to its previous bone-dry condition.
While the track was still sticky and wet, the Stinger chassis did well with four 01 pads, but as soon as it dried out, the high-friction pads were too much for the conditions. Hargett had trouble just getting the car set up for the corners and had to fight to keep the rear end of the car from passing the front.
"That's more brakes than I've ever run before," Hargett said after the first run with the 01 pads. "Usually, I have to wait on the brakes, but I'm not waiting on these. These would be really good when the track is wet and tacky and you are getting a lot of traction, but on a dry-dusty track it's just too much braking power."
After discussing the car with Gipson, the team switched to a set of 97 pads, which have a lower friction coefficient and ran several laps. That, Hargett said, brought the car back in line with what he was used to. From there, the experimentation continued. All tests began with the brake balance bar centered, and Hargett adjusted from there to dial in the feel he wanted.
"Given the track conditions, we are going to try a lower-friction set of 80 pads in the front and keep the 97s in the rear," engineer Gipson said. "We are going to the least amount of friction in the front with the next progressive in the rear. That's basically going to take some of the brake grip out of the front but keep it in the rear to help get the car rotated.
"This may not be the best setup for a wet, grippy track, but I think it will allow Chris to get a feel for what he wants and when he gets in a competition situation on a surface with better traction he can just go with stronger pads."
Hargett said he liked that setup and felt it complemented his driving the best. "I don't like the front end of my car to do a lot of bucking," he explained. "I like the back end to turn the car getting into the corner and to help set the car up so I can get back into the throttle quickly and drive off. I like to set the car up by turning in and getting on the brake at the same time, then as soon as I'm off the brake pedal I want to be able to get back on the gas and get on out of there. I think this is the feel I like best, with a bit more braking power in the back than in the front to help swing the back end around. I don't think what's on the car now will have enough braking power on a wetter track with lots of traction like I normally race, but it does give me a good feel for what I'm looking for."
By this time it was the middle of the afternoon, and the track surface was not going to allow any traction no matter what we tried, so with plenty of good information to sleep on, we called it a day. After discussing their options with Gipson a little more, Hargett and Wilson went racing the next weekend, with the high-friction 01 pads on the car in a three-brake setup, two in the back and the third on the left front. The right front brake was shut off. This gave them the extra braking power in the back they were looking for to make the car looser and also matched up the stronger pads with a track that they knew was going to keep its traction at night.
"It's a good setup, and I think it's going to work pretty well for us," Hargett said between hot laps and the first heat race that Saturday night. "We've got a lot left to work on with the car, but getting to change a few things with the way the brakes were set up has helped us get a little closer to what we were looking for.
"I'm ready to go racing." CT
The night before the test;...
The night before the test; new P.F.m rotors (PNs 299.32.0040.0, front; 299.32.0040.02, rear) were installed on all four conrners of the car.
This wasn't just a brake test,...
This wasn't just a brake test, HHH Motorsports was also shaking down a new engine. The crew checks a couple of details while Performance Friction's Brett Gipson (background right) and driver Chris Hargett discuss how the different pads are affecting the car's handling.
Gipson applies rotor paint...
Gipson applies rotor paint to track the maximum temperatures the rotors and pads are reaching. No test is much good unless you are trying to gather every bit of data you can use to go faster. Brakes on a dirt car usually don't see the extreme temperatures associated with asphalt racing. Generally, 800-1,000 degrees is considered the optimum range. We were never able to reach that with the dry/slick track conditions, but the team plans to, once the car returns to competition.
By midday the combination...
By midday the combination of direct sun and a steady breeze had made the track extremely dry and dusty. There's a reason they call it Saturday-night racing.
Hargett and crew chief Neil...
Hargett and crew chief Neil Wilson kept a constant dialogue of how the car was reacting to the different adjustments they were trying.
Performance Friction rotors...
Performance Friction rotors and pads are good for a brake test, because when used together they do not require an extensive bedding-in process.
Once Hargett returned to the...
Once Hargett returned to the racetrack competitively, the team had decided to go with the 01 pads (strongest friction) in a three-brake setup to help get the car turned on corner entry.
For rotor installation, Performance...
For rotor installation, Performance Friction offers these special bolts with a round collar just beneath the hex head. They are designed to lock the rotor against the hub more firmly and prevent stress cracks from developing.