Before we get started, let me say that the information that follows is based on my own personal experience.  I have been racing for 5 years now and have over 1,100 passes to look back on.  This doesn’t necessarily mean that I’m an expert but I’ve tried just about everything and have found that certain things work for me.

One of the most important aspects of drag racing is your reaction time.  There are actually a number of factors that affect reaction times, the time it takes you to react, the car’s reaction time, and rollout.  Each of these need to be understood in order to get good, consistent reaction times.  When you take all of these factors into account, it’s easy to see why you need to leave on the yellow light and you can’t wait until the green light comes on to leave the starting line.  If you wait for the green light, you will surely lose the race.

Your reaction time is the time that it takes for your eye to see the light, your brain to react and then to hit the gas pedal or release the button attached to the transmission brake.  Studies show that most people have a reaction time of around .200 - .250 seconds.

Your car also takes a certain amount of time to react.  The car has to release the brakes, rev the motor a bit, and move the suspension around a bit before it starts moving forward.  Again, this takes a little bit of time.  Your vehicle’s reaction time is difficult to predict because there are so many factors, but there are things that you can do to speed it up or slow it down in order to fine tune it.

The next thing is rollout.  Rollout is the distance that the car must travel in order to actually break the starting beam, or more accurately, to un-break the starting beam.  When you get your car staged, your front tire is blocking the starting beam.  The ET timer actually starts when your tire clears the beam.

When you shallow stage (ie:just barely light the stage light) your ET will improve because you get more of a rolling start before you break the starting beam.  Conversely, when you deep stage your ET will slow down because you are closer to the starting line and get less of a rolling start before breaking the starting beam.  I’ll discuss this a little bit more later on.

So, putting this altogether you can see why you need to leave off of the last yellow light in order to get close to the perfect .500 reaction time.

Lets say that your reaction time is approximately .200 seconds.  We’ll combine the vehicle reaction time and rollout because they are difficult or impossible to determine independently and say that this is .350 seconds.  This is about right for my mid-13 second street car.  This gives us a total of .550 seconds.  So if I leave the instant that the last yellow light comes on, the best reaction time I can get is a .550.  Clearly there is room for improvement.  I’ve won races with .550 lights, but I’ve also lost a lot of races with .550 lights too.

So, what can we do to improve our reaction times?

• Anticipate the last yellow light and leave just before it comes on.

• Bump in a little bit deeper after you get staged or Deep Stage

• Make the car react faster

The paragraphs that follow are some suggestions for improving your reaction times.  You will find that in all cases I recommend that you go to the track on a test-n-tune day to experiment and find out for yourself what effect they have for you.  I cannot give you exact recommendations because every person and every car is different.  Just go to the track and try some things.  Oh yeah, be sure to keep good records so that you can refer to them later on.

Anticipating the last yellow light

Anticipating the last yellow light almost always results in inconsistent reaction times.  It’s extremely difficult to anticipate the last yellow light the same amount every time.  I cannot recommend this technique because it really never worked too well for me.

Bumping in

Bumping in is a technique used by many racers.  Unfortunately it has one major drawback.  It can be difficult to "bump-in" the same distance every time.  When I say bump-in I mean that once you get fully staged you move forward another inch or two.

If you want to try this technique, draw a line in you driveway and pretend that it is the spot where you are just barely staged.  Now, let off the brake pedal and try to move in another inch.  Try this a whole bunch of times and see if you can move exactly the same amount every time.  It's a lot harder than it sounds.  You’ll probably end up moving a different distance each time. For many, if not most people, this results in inconsistent reaction times because the rollout is different every time you stage.  Not a good thing.  You also need to be aware that when you stage deeper, your ET is effected too because now the car does not have as much distance to get moving before you break the starting beam.

Deep Staging

Deep Staging is when you continue to move towards the starting line until the Pre-Stage light goes out.  This means that you are really close to the starting line.  Deep staging reduces your rollout dramatically but also slows down your ET because you don’t get as much of a running start before breaking the starting beam.

Let me give you an example based on my own experience.  One week I blew up the transmission in my regular bracket car so I took my wife’s 1990 Cavalier station wagon out to the track instead.  This car had a 4 cylinder engine with 175,000 miles on it so it was considerably slower that what I was used to.  During time trials, my first two attempts resulted in .620 and .630 reaction times. Clearly I was not going to win many rounds like this so I tried deep staging.  The first time I deep staged I got a .526 reaction time! On the other hand, I went from a 18.95 to a 19.08 ET.  Almost exactly the amount of time that I picked up in reaction time but heck, I’ve got plenty of shoe polish so I just changed my dial-in.  I continued to deep stage all night and my worst light was in the .540’s.  I ended up losing in the finals because I broke out.

The moral of the story is that if you deep stage, be prepared to make adjustments to your dial-in.  I’m not saying that you will pick up a tenth of a second in reaction time and lose a tenth in ET, that’s going to depend on you and your car.  Try it out at a test-n-tune session if you think it might help and don’t be surprised when your car slows down for no apparent reason.

Making the car react faster

My personal opinion is that you should find a comfortable spot on the tree and try to adjust the car to react faster.  The hardest part is making the driver consistent, changing the car is much easier and results in more consistent reaction times.  Once the driver is consistent you can fine tune the car to make up for either too quick or too slow of a reaction time.

This can be accomplished in a number of ways including adding horsepower, changing your launch RPM, using different diameter front tires, and raising/lowering the air pressure in your front tires.  Adding horsepower will usually not be a practical solution so that leaves the other two options.

Changing your launch RPM is a great way to adjust your reaction time.  It’s easy, doesn’t cost anything, and you can make this adjustment at any time.  You should try this out at the track on a test-n-tune day to see what effect it has for you.  It is impossible to predict because every car reacts a bit differently depending on your engine’s torque curve, your torque converter, and the braking ability of your car.  Like I said, try it for yourself and see.

Using different diameter front tires can have a dramatic effect on your reaction time.  A shorter tire will make your reaction time faster while a taller tire will slow your reaction time down.  If you find that you are red-lighting all of the time, use a taller tire.  If you are cutting consistent .580 lights, you need a shorter tire.  Once again, experiment at the track until you find the right combination.

Another way to adjust your vehicle’s reaction time is to increase/decrease the air pressure in your front tires.  This is really more of a fine tuning technique that can be used once you have the basic combination sorted out to adjust for different conditions.  After you race for a while you’ll notice that you have good days and bad days as far as reaction time is concerned.  This does two things, first of all it changes the diameter of the tire allowing the starting beam to "see" and secondly it increases or decreases the rolling resistance of the tire.  A 2-3 psi change might be just enough to get you into that magic 5’oh or 5-teen reaction time that you are looking for.

Summary

If you take the time to try these things out at the race track on test and tune days, keep good records, and pay attention to the details, you will be able to adjust for days when you just seem to be hitting the tree badly (too fast or too slow).  Experience is the best way to find out what works for you.

Here’s another story that illustrates this point.

At the 1997 Division 1 Bracket Finals a Lebanon Valley racer named Russ Wilbur had reaction times in the .590’s for his first two time trial runs.  Russ has been racing the same 1967 Chevy Biscayne station wagon for over twenty years and was our track champion in 1997 so these were not typical reaction times for him.

He was quite concerned about this so he thought about it for a while and the next day put a shorter pair of tires on the front of the car, made some air pressure adjustments, and raised his launch speed a few hundred rpm’s.  When he made his next pass, he cut something like a .518 light!  Man was I impressed!  I couldn’t believe it!  Russ really knows his car, keeps records of everything, and takes his racing very seriously.  It’s easy to see why he has been so successful in bracket racing.