Race 5: Brakes Afire

Eagles Canyon Raceway is a relatively new track, nestled in the rolling hills northwest of Denton in north Texas.  Nobody on our team had ever been there before, but everyone told us it was a fun track, lots of elevation changes, and very hard on brakes.  Everyone was 3 for 3 on that review.
We got there Friday afternoon in time for everyone to run a handful of practice laps.  All the long straights had us worried.  We didn't think we had enough horsepower to be competitive.  There were some strong cars racing this weekend, with V8 power.  We were going to have to live on our combination of light weight, 2-hour stints, and good pit stops.  Even then, we figured that cracking the top 10 would be a feat.
A few minutes before 9:00 a.m., the cars began rolling out on track.  ChumpCar doesn't do organized starts.  The starting procedure is to get all the cars out on track, circulating under yellow, in order to check transponders and get the jitters out.  Once everything is in order, they pick a car at random, and throw the green flag.  It's a good way to safely start the race without a first-turn pileup, but there is one obvious disadvantage.  You might be caught almost a complete lap behind the newly-crowned leader.  When a lap is over 2 minutes long, you can start at a pretty big disadvantage.  But over the course of the race, it works out, and the disadvantages are far outweighed by the safe, orderly start to the race.  And since we have radios, our first driver always knows as soon as the green flag drops.
John was our first driver this day.  He started the race in 23rd place out of 37 cars.  John began clicking off lap after lap, steadily moving up the lap charts.  He even passed 4 cars in one corner early in the race.  In spite of our doubts about cracking the top ten, John was up to 5th place when it was time to pit. 
Tobey was the next driver.  The pit stop took just a tick over the 5 minute minimum as all the tire pressures were reset, but he joined the race in 11th place.  Tobey's position gradually improved, until he was up to 6th place.  However, in gaining that position, he had a multi-lap battle with an E36 BMW.  The BMW was a bit faster in the straights, but slower under braking and cornering.  The driver continually blocked the pass attempts, moving all over the track, making the pass very hard to perform.  After 2 laps of being very hard on the car and the brakes, Tobey finally got around the BMW, and built up some space.  But the damage to the brakes was done.
Within a lap of passing the BMW, Tobey was heading into turn 6 when the brake pedal got a little soft.  The car stopped fine, but the pedal didn't feel right.  So on the next straight, the fastest part of the track, he let off about 200 yards early to test the brakes.  And a good thing he did, as the pedal went straight to the floor.
He pumped the pedal several times, then for lack of anything better to do, he pushed really hard, and was able to lock up the rear tires.  He couldn't modulate the brakes at all, so to keep from spinning, he pulsed the rear brakes, slowly bringing the speed down.  He was still going too fast for the corner, but pitched it in anyway, allowing it to slide sideways and scrub more speed, and managed to keep it under control and on the track.  He took it straight to the garage, where he was met by Thomas and John.  As Tobey unbuckled to get out of the car, Thomas remarked, "Hey, the brake's on fire.  Pretty green flame."
They doused it with water, and took it apart, to find that the pad, which was a brand new Hawk Blue 3.5 hours earlier, had melted, the backing plate had bent around the piston, and the piston was overextended from the caliper.  This let the fluid leak onto the hot rotor, causing the fire.
The team immediately jumped to work.  As Thomas kept pouring water on the brakes to cool them off enough to work, they got the spares and tools from the trailer, and in 45 minutes, had both front rotors, both front calipers, and the front brake pads replaced, bled, and ready to go back on track.
Clark was the lucky guinea pig with the new brakes, and headed back out in 27th place.  Clark went out with instructions to baby the brakes, as we had no more spares, and these had to last another 7.5 hours Saturday and 6 hours on Sunday.  Even taking it easy, Clark knocked out consistent laps, and pitted in 23rd place.
Thomas was next, and went out in 24th place.  He ran really well, gradually moving up through the field, and pitted in 19th position.
At this time, our ability to run for a full 2 hours on fuel started playing to our advantage.  Under ChumpCar rules, drivers are limited to running for a max of 2 hours at a time, and if you put gas in the car, you have to stay in the pits for at least 5 minutes.  No 15 second stops like in NASCAR.  The reason for this 5-minute rule is safety.  We are only allowed to fuel from 5-gallon jugs.  With the 5-minute rule, there is no pressure to do anything stupid with your fueling setup and compromise safety.   That's also plenty of time to change drivers, and get the new driver properly belted in.
Not every car has the fuel capacity and economy to run for the full 2 hours allowed for a driver.  In a 12-hour race like Saturday, we can do it with 6 two-hour stints, and 5 fuel stops.  Many of our competitors needed 1 or 2 extra stops.  Each extra stops translates into 2+ extra laps for us.
With Thomas in, Tobey went out for the second time on Saturday.  He started in 21st, and gradually moved up.  When the sun set, his experience from racing at TWS at night, along with the 4 well-aimed HID driving lights, allowed him to maintain his speed.  It was also nice that the track had reflectors marking the corners and braking markers at the end of the straights.  These helped immensely.  Tobey pitted in 16th place, turning the car over to John.
John left the pits in 18th place, and did some excellent night time driving.  He steadily moved through the field, and after 12 hours of racing, including the 45 minute stop for new brakes, we finished up in 12th place.
Sunday morning, we showed up bright and early to get the car ready.  Today's race would be only 6 hours long; the shortest ChumpCar race any of us can remember.  We had to use 4 drivers, at least one hour each.  Many teams divided the race into four 1.5-hour segments, making 3 stops for fuel and driver changes.  We decided to go 2-2-1-1, and make only 2 fuel stops and 1 driver change.  Hopefully, that would gain us a lap on the field.
We also had to take it really easy on the brakes.  The previous day had used up about half the pad material, and the last half of the pad never lasts as long as the first half.  It has to do with less material to absorb and disipate the heat.  As the pad gets smaller, it stays hotter, and wears faster.
Clark went first, with instructions like yesterday to baby the car.  Unfortunately, the lap-by-lap results are not available for Sunday's race, so we don't know where we started, or Clark's position when he pitted.  But he knocked out consistent laps and kept his nose clean.  The pit stop was perfect, and Thomas went out next.  Much like Clark, Thomas ran very consistently and cleanly, slowly moving up through the field.  If memory serves, Thomas was running 6th or 7th when he pitted, and was replaced by John.
John ran his normal fast pace, and in his one-hour, managed to move up to 4th place; 6 laps ahead of 5th place.  Our strategy was working perfectly as our driver change neared.  Then, it happened.  John radioed in, "The brake light is  on."  We needed John in the car for an hour, so he stayed out, being extra careful.  Then, right before he pitted, the brake pedal went soft.
When Tobey got in for the last hour, the pedal was going to the floor with minimal resistance.  The team topped off the master cylinder, and after much pumping of the pedal, if finally firmed up.  Tobey went out, still 5 laps up on 5th place, just trying to limp it home.  He made it almost 2 complete laps before the brakes failed completely.  Luckily, he was already slowed down for turn 11, so no drama ensued.  But as he pulled into the pit stall, the passenger side brake was on fire, much like the previous day.  It was not the way we wanted to go out, as that top-5 finish was in our grasp.  We ended up in 11th place, even though we didn't finish the last 45-minutes of the race.
Next up:  24 Hours of Texas World Speedway, and bigger brakes.