A dial-in time is used to establish a handicap start in a bracket race. The dial-in is the driver's estimated elapsed time (ET) their car will run in competition, and allows just about any two vehicles to compete with a handicap start. This makes it possible for a street-driven 4-cylinder compact to compete with a purpose-built, big horsepower race car and have an equal chance of winning. When two cars are matched up for a race, the dial-ins are compared and the slower car is given a handicap, or a head start, equal to the difference between the dial-ins. It's not just a race of car vs. car, but driver vs. driver to see who can run closest to their dial-in to take the win light.
A racer uses time trial practice runs to determine the elapsed time they think their car will run. Beginning racers usually base their dial-ins on a few passes down the track. For veteran racers, a dial-in is serious business based on years of experience, countless runs and the use of sophisticated real-time weather data. A good bracket racer can hit on or within a hundredth of a second to their dial-in almost every time.
There are two winning scenarios:
When a driver runs an elapsed time (ET) that's numerically lower that their dial-in. For a drag racer, a break out is a losing scenario – except when the car in the other lane breaks out worse and goes further under (quicker) than its dial in.
The package describes the starting line reaction time and the ET versus the dial in.
Package = (ET – Dial In) + Reaction Time
The winning package is always the numerically lower of the two racers, and the perfect package is .000, meaning the reaction time was a perfect .000 and the car ran exactly its dial-in.
While ET is measured over the full 1,320 feet of the drag strip, MPH is measured in the last 66 feet (the trap) of the quarter mile. A small-engine, lightweight car geared for quick acceleration may have a 12.0-second ET with a 115 MPH. A big HP late model muscle car on street tires won't have the same rate of acceleration, but will have a strong MPH – running a 12.0 ET and 125 MPH. There is widespread respect for MPH as a measure of pure horsepower. Big MPH is impressive, and brings with it the notion of big power.
A delay box is an electronic on-board timer for the transmission brake, commonly referred to as a transbrake. Launching a race car with an automatic trans and a transbrake is similar to dumping the clutch with a manual trans car. The transbrake internally locks the transmission to allow the engine to be revved – and then it's released by an electronic solenoid.
With today's sophisticated race car chassis designs and sticky tires, it's typical that the driver can react to the Christmas tree quick enough to red light – leave too soon and be disqualified. The delay box is adjustable to set the exact time from when the driver releases the transbrake button and the signal to the transmission to internally unlock occurs – and the race car breaks the starting line beam.
A driver instinctively reacting to an initial signal (the first amber) will be quicker and more consistent than a driver that waits for the third amber. This is often the case, making the box a controversial (but legal) tool in many classes.
Drag racing is all about accelerating mass, so it makes sense that the lighter an object is, the quicker it is to get moving. Strip down the body, get the weight as low as possible and quicker ETs and higher MPH will follow. A walk through the pits at any drag race will show lots of creative solutions to getting the weight out of a race car. From simple no cost solutions like removing parts and equipment, to high cost options like lightweight fabricated components, aluminum instead of steel and exotic carbon fiber body panels. The general rule of thumb that says that for every 100 pounds of weight change, there will be a tenth (0.10) of a second change in ET. Less weight means less stress on components, especially the parts in the driveline. Lighter is always better in drag racing.
For a lot of drag racing fans, the launch of the car from the starting line and the first 60 feet can be the most exciting part to watch. Wheelstands, the scream of the engine, the occasional tire smoke and a driver fighting for control are what make drag racing so exciting.
Improvements in the 60 ft. time are magnified on the E.T.
The perfect hook – no tire spin - is the key to not only good, but also consistent 60 ft. and overall quarter mile times. The best possible launch is obtained by striking the optimal balance of putting the most power to the ground with the least amount of wheel spin. Too much power and the tires spin resulting in a poor 60 ft. time. Transmission, torque converters and gearing can have a big impact on the 60 ft. time. High stall torque convertors in automatic trans cars and high tech clutches on manual trans cars combined with numerically high rear axle rations are keys to launching a race car quickly and efficiently. The perfect combination of gearing, tire size and torque convertor or clutch is what separates the winner from the runner up.
The Christmas tree has two stage lights – Pre-Stage and Stage. When deep staging, the driver rolls the car a few inches forward past the Stage position, which is noted when the top Pre-Stage light goes out. In most cases, the reason to deep stage is driven by reaction time. One of the best spots for a driver to react is when the last yellow comes on. But for slower reacting cars, that spot will usually produce slow reaction times that make it tough to win when bracket racing. By rolling in deep, the car will clear the stage beam sooner producing a lower or better reaction time. When deep staging, the E.T. will just about always be slower since the car has less of a head start or run at the starting line.
Anything you can leave at home or in the pits to reduce weight will help lower your E.T. From floor mats to anything in your trunk, loose items not only add unnecessary weight, but can be projectiles should an accident occur. Take them out to help shave a few more hundredths of elapsed time.
The first stop is the water pad or burnout box. All tracks a have a worker that will guide you through the wet part of the burnout pad to the front edge where you will stop to start the burnout. It's not uncommon to see cars with street tires drive around the water and back into the burnout box. The deep treading of the front tires will drag water from the burnout box to the starting line leading to tire spin.
The command to start the burnout will happen once the cars in front of you have left the starting line and are making a clean run down the track.
After your burnout, you'll approach the staging beams slowly to be sure you don't drive through them. The starter will signal you if you need to wait before approaching.
All tracks require courtesy staging, where both cars must be pre-staged before either car can proceed to stage. Once one of the cars is staged, the auto-start timer begins, allowing the other car just 7 seconds to complete its staging process. If the second car takes more than the auto-start 7 seconds, it will receive a red light or foul start. Once both cars are staged – it's time to race!