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Delay Boxes


Disclaimer: While based on facts about drag racing, this page contains the personal views and opinions of one racer - Michael Beard


After reading the Reaction Time Clinic, you may be a bit overwhelmed by the apparent difficulty of "cutting a good light". Evidently, some very intellingent engineering racers thought the same, because the delay box was invented. I believe Ike Hamma, a very successful Sportsman class and ET racer, of Digital Delay is credited with the creation of the delay box.

What was the major problem with trying to get consistently good reaction times on a Full tree? I briefly mentioned the subconcious mental factor of anticipation. In order to make our r/t's as consistent as possible, we want to rid ourselves of this variable, presumably reacting to the last light as an instinct, rather than a conciously controlled thought process. From these statements, it follows that leaving at the very first glimpse of the very first amber bulb would be optimal for our reaction times. This is exactly what a delay box allows us to do.

The "box", as it is usually called, is an electronic device to aid the driver. The driver can 'dial' a number into the box, called the delay. Usually used in conjunction with a transmission brake and two-step, the driver can hold down a button mounted on his steering wheel, activating the transbrake and two step, and then let go of the button the instant he sees the "first flash" of amber from the first bulb. The delay box will then count the thousandths of a second dictated by the driver, and then release the transbrake and two-step.

Dr. Larry Rose's Olds The driver can adjust his reaction times by changing the number on the delay box. The theory is that a driver instinctively reacting to an initial signal (the first amber) will be quicker and more consistent than a driver that must train himself to wait for the third amber. This is indeed often the case, making the box a controversial (but legal) tool in many classes.

Let's go back to our simple math to see how the dealy box accomplishes its task. Remember our 'given's in the problem: Our driver reacts with DRT = .210 seconds, the vehicle at VRT = .320. The reaction timer starts when the third amber comes on, which is exactly 1 second after the tree is activated. This means that there is 1.5 seconds between the first amber and the green light.


	First Amber:  .000
		DRT:  .210
	+       VRT:  .320
        ------------------
	  Total r/t = .530


	First-to-Green: 1.500
        -    Total r/t:  .530
        ---------------------
	Delay setting :  .970

So, if I have a delay box in my race car leave off the transbrake button the instant I see the first bulb, and my DRT = .210 and my VRT = .320 like I assumed, and put .970 in the delay box, I will have a perfect .500 reaction time. Of course, it is not as simple as all that. Of course my reaction time and the car's reaction time will vary, so I try to guess what they are going to be on the average and put the appropriate number in the delay box. Since driver and vehicle reaction times can vary so much, I am led to wonder how much effect is had when a racer 'takes a couple out of the box', or lowers the number in the delay box. If he takes .005 out, his r/t should technically be that much better... but it is very easily possible for his reaction time to be slower because of inconsistencies in both the human and the car.

Cross-over delay boxes make a good tool even deadlier. With a cross-over box, the driver can input both his dial-in and his opponent's during eliminations, if he is the faster car. The box figures out the handicap, and adds that to the delay, such that the driver can leave off his oponent's first amber. This has the advantage of letting the driver leave off a 'clean tree', meaning there are no other amber bulbs flashing on the tree to distract him. Important: Keep in mind that when you cross over, you are not seeing your opponent's bulbs the same that you would your own. This is because the starting lights are angled away from the center of the track. Because you are seeing the bulb from an oblique angle, you will not see it as brightly, and should thus take .005 to .010 out of the box to compensate. Note also that the bulbs will appear brighter at night than in the day, on both sides. This makes the signals register in your brain faster at night than in the day, so you should put some into the box to avoid red-lighting.

While delay boxes have become an integral part of higher-level bracket racing, they are illegal in many classes except these Super/Pro classes in each NHRA Division. Many racers are dead-set against boxes, and other rely on them. Fact: Delay boxes are here to stay. Delay boxes do not make a perfect racer, though, not by any means! To quote many a knowledgeable racer, "A box makes a bad racer good, and a good racer better." It is very important to remember this, and that the box is merely a tool, not a definite win. The driver must still react.


Copyright 1996-1999 Michael G. Beard

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