Drag Racing with Jim Hand – Part 6: More Drag Racing Basics
- March 16th, 2010
- Posted in Jim Hand: Drag Racing . Technical Articles
- By D.A.P.A
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We concluded part 5 of this series by mentioning that there are many good drivers in Bracket Racing. Drivers that practice regularly become “good” drivers. However, knowing how to practice, and knowing the relationship of reaction time/elapsed time/winning/ losing can help you progress faster.
Do not waste any runs! Try to improve your reaction time each run, regardless of whether you are tuning or checking out your vehicle. Work out your staging routine and then follow it exactly each run. I use the following procedure each run of practice and elimination’s.
When the starter motions us to stage, I slowly drive into the first light. The transmission is placed in neutral and the throttle is blipped hard enough to open the carburetor secondaries. (This assures the intake system has not loaded up which could cause a hesitation when the throttle is floored to leave.) After the other driver has turned on the top light, I raise the RPM to 1200 to 1300 (RPM at which I leave) and bump the car forward using the foot brake while holding the throttle steady When the second stage light barely lights, I stop. The RPM has already been set so I don’t have to look away from the starting lights. When I see the third starting light, I floor the throttle while simultaneously releasing the foot brake.
This routine has been worked out based on the front tire diameter (rollout), the rate at which the car moves upon initial acceleration, and upon my brain-to-feet reaction time. You may have different ways of staging, but the important aspect is to be consistent and practice your system each and every run.
While we all want to obtain the quickest elapsed time (ET) possible, consistent ET’s are much more important in bracket racing. If your vehicle is inconsistent, you can’t run your dial. As we pointed out previously, .1 second on a 95 MPH vehicle is about one car length. Many races are won by hundredths of a second, and I have won by less than one thousandths of a second. The following basic steps will help your consistency; Stage and leave identically each run. Shift at the same RPM each run. Experiment with the air pressure in your rear tires to find what produces the best 60′ time. Try to drive your vehicle straight down the track without swerving. Never make tuning changes and don’t add or delete weight to/from your vehicle when running time trials for a bracket race or during the race. Be aware of weather changes and dial accordingly. In general, weather affects performance as follows: a tail wind quickens the ET, and a head wind slows the ET. Increased heat as well as increased humidity slows the ET. Higher atmospheric pressure quickens the ET. The combinations of these factors can be unpredictable, and only close observation of weather effects on your vehicle during each trip you make to a strip can prepare you to include weather in your selection of an accurate dial-in. If your track’s time slips list 1000′ times refer to these to determine your vehicle’s performance if you intentionally slowed the previous run to avoid break-out. If the lOOO’ time varied from previous runs, you should probably dial accordingly for the next run.
How about speed as a factor in bracket racing Speed, or crossing MPH, does not have a direct bearing on the outcome of most bracket races. For example, my wagon can run 111 MPH, but many vehicles that can run only 106 can run a quicker ET. They will accelerate quicker during the initial portion of the race, (which places them out front of my wagon), but run out of RPM during the final part of the race. Their top speed may be reached prior to the finish line because all of the available power and RPM was used in the early part of the race to obtain the quickest ET but they have enough lead to stay in front through the quarter even though my wagon may be gaining (pulling) on them at the finish. Since my wagon is setup for normal road driving as well as some racing, it has enough gearing to run well past the end of the quarter, and is still accelerating (gaining MPH) at the finish line.
Indirectly, speed does affect how drivers may choose to run the race. We never want to run a quicker ET than necessary to avoid “breaking out”. Accordingly, a driver that is comfortably ahead during a race will usually slow down prior to the finish line. If he/she misjudges the speed of the faster car and slows down too much or too early, the faster car may drive by and win. Conversely, when the fast car runs a very slow car, the fast car has to decide whether to let off before catching the slow car, or drive it hard all the way through (also called “running it out the back door”) and risk break out.
We touched on selecting a dial, and I suggested that you dial what you can run. Some racers will under dial by several hundredths from what they can run, and then attempt to use the brakes to barely stay ahead of the opponent. This can be successful, providing you can consistently have equal or better reaction time than your opponent. However, if your reaction time is poorer, you will usually lose by a break-out against a good driver. I again suggest you dial just what you can run, and if you are ahead at the finish, slow down. Otherwise, run it clear out and you should still be “safe” from break-out. The closer to the end of the race you slow down, either by letting off the throttle, or hitting the brakes, the less you will affect the ET. Remember, most of the ET is made at the start and through the mid portion of the race, so slowing from 110 to 105 right at the finish line may affect the ET less than .01 of a second. Conversely, a bog on the start, or a missed 1-2 shift may cost a full .1 second or more of ET. Do a little experimentation in this area during practice runs to find out what actually affects your ET. You will then be better prepared to implement the correct strategy during your elimination runs.
Practice your reaction times continually and be alert as to what may cause your vehicle to change ET from run to run. These are the things that make the difference between “Just another old Pontiac running”, and “WOW, watch that Pontiac go!”