In my last column I discussed the importance of periodically inspecting various components on your race car such as suspension. In addition to the safety aspect, I mentioned the fact that loose suspension components can rob your car of reaction time. Now that spring is approaching and a new racing season is upon us, I thought it might be timely to delve deeper into reaction time. Having a better understanding now will be beneficial as racing gets under way.
Whether you race on a .400 or .500 Pro or Sportsman (full blinkdown) tree reaction time is critical to being successful at dial-in or index racing, yet there are racers who don’t really know what it is. Sure, they know it’s a number on the time slip that describes how closely the car left the starting line in relation to the green light coming on, but they’re not really sure what it comprises.
Reaction time is made up of two primary components: the driver’s reaction to the Christmas tree and the car’s reaction to the driver hitting the throttle. How the car is staged is also a factor, but we’ll leave that out of this discussion for simplicity.
Let’s look at the first component, driver reaction time. Knowing your own driver reaction time is the first step in mastering the overall reaction time equation. Skilled and knowledgeable racers have determined theirs, and it’s really quite simple to figure out. You will need a practice tree to do so; there are many available on the market. I suggest a tabletop unit, although a hand-held or full-size will certainly do.
Practice trees have different settings to account for the different types of Christmas tree settings; they also have rollout settings to approximate the second component of reaction time, vehicle reaction time, as well as delay settings for delay-box racers. The first step is to set up the practice tree to determine your driver reaction time. Since many of us normally race on a .500 Sportsman (full blinkdown) tree, that’s the tree we’ll use for this discussion. First, you must set the tree’s delay and rollout to zero (.000). Next, set the tree to .500 Pro (that’s not a typo, .500 Pro tree is correct). Set the tree up for single-lane operation, or if it’s two-lane, remove any handicap start from either lane: You want both lanes to light up at the same time.
Now it’s time to start hitting the tree. Hold the trigger button, pre-stage and stage your lane, and then let go of the button as quickly as you can at the first hint of amber flash. Do this five times to get comfortable, then for real another 10 or more times and jot down the resulting reaction times. Because you’ve removed all rollout, you will be red every time. That’s OK; you’re just collecting data. Add up the 10 or more hits, and then divide by the number of hits to find your average. Mine were: -.348, -.348, -.328, -.351, -.351, -.354, -.358, -.352, -.359 and -.337; the average is -.349. Subtract this number from .500 to determine your own driver reaction time. In this case, my average driver reaction time is .151. You now know half of the overall reaction time equation. From here it’s time to set the tree up for green lights.
Let’s say you want a target green light of .010. Simply add a sufficient rollout to your average driver reaction time. In this case it would be .151 + .359 = .510, which is a .010 green light. Still using a .500 Pro tree, do another 10 hits. With the addition of the rollout, you should now be hovering around that .010 reaction time.
Now the fun begins. Set the tree to .500 Sportsman so that it’s a full blinkdown, and focus your eyes and brain solely on the bottom amber—your world now revolves around that bulb. Take another 10 or more hits and jot down the resulting reaction times. If you’re now coming up with a bunch of red lights, then you’re anticipating and jumping the last amber. If you’re now coming up .030s or later, then you’re sitting on the amber. It’s important to remember that when racing on a .500 Sportsman tree, the first and second ambers are only there to distract you. You must try to ignore them so that your reaction time is the same regardless whether or not you’re using a Pro tree or Sportsman tree.
Next time, we’ll take a closer look at the second half of the equation, vehicle reaction time. Thanks for reading.
Bob Beucler is the publisher of The Dragtime News (www.dragtimenews.com (http://www NULL.dragtimenews NULL.com)), which promotes racing at 32 dragstrips from Alabama to Maine. His Dragtime ‘64 Dodge Polara is known at many tracks in the mid-Atlantic and Northeast. Contact Bob at firstname.lastname@example.org (bbeucler null@null dragtimenews NULL.com).