ZZ28ZZ

Just made my first run down a dragstrip last night.

Looking at the time slip, I have a question.

1/4 mi ET; does it start counting when the light goes green, or does it start when a 3rd beam is broken with the front tires at the start line, or does something else start it?

What I really want to know is; if I have a better reaction time, will my ET be any better?

I wanted to ask the dragstrip staff, but didn't want to look like a total idiot..

BRIrocZ

iTrader: (1)

When the beam is broken the reaction time clock stops and the ET clock starts.

Good traction = Better 60' = Quicker ET.

Your from Austin, did you run at RCR?

AlkyIROC

When the light turns green you can sit there as long as you want. The timer doesn't start until you break the start beam. RT has no affect on your 1/4 mile time however in an actual race, RT can be a deciding factor as to who will win.

A few years ago during a test and tune I launched on the last yellow light. The car bogged and stalled and I never rolled forward enough to break the start beam. Ratchet shift out of first to neutral, start the engine, ratchet shift back down into first and go! 8 second reaction time. ET was the same as normal.

I'm glad it was only a test and tune. The car in the other lane was half way down the track when I finally left.

The reaction timer starts when the last yellow light comes on. If you launch before then you get a red light and a .000 reaction time. .500 seconds after the last yellow light comes on the green light comes on. You leave on that last yellow light. By the time you and the car react and start to move, the green light should be on. If you wait until the green is on before going, you'll be too slow and get a bad reaction time.

Deciding when to go on the last yellow takes practice. If you watch the light close enough you can actuall see it come on and go out. It doesn't just flash. Most people will adjust themselves to go when the light is at it's brightest. Depending on how your car reacts, you have to adjust to when it gets the best reaction time.

Racing at night usually gets better reaction times because the lights are brighter.

MdFormula350

what time / 60 foot did you run ZZ28ZZ?

ZZ28ZZ

Thanks Stephen!
I must have looked pretty foolish.
I waited till I saw green before I punched it.

Let me see if I got this straight;
1. When both drivers break the second beam the Christmas tree starts its' sequence.
2. When the last yellow light is at max brightness, I start my launch.
3. As I roll a small amount fwd, I break a third beam (?) which stops the reaction timer and begins the E/T timer.

Are the 2 yellow lights in the sequence timed .500 secs apart like the last-yellow-to-green light timing is?

The run ("the run of shame") was a "before run" in preparation for a "before and after" comparison.

I have a TPI 383 going together to replace my almost (has a "RV" cam) completely stock CFI 305. Hope to eventually be in the 12s after I get all the bugs ironed-out.

Anyway, here my results from the best of 2 runs:

Reaction= 1.3127 (waited till I saw green )
60'= 2.3666
330'= 6.7084
1/8 ET=10.3983
1/8 MPH= 66.06
1/4 ET=16.2911
1/4 MPH= 82.78
Winner!! (went up aginst a Eclipse!! )


BRIrocZ>>
I actually live in Georgetown, so Temple is a lot closer than RCR.
Never been to RCR. A guy I work with races a 'stang and his Firebird down there. I'll probably head down there with him one of these days.

AlkyIROC

1. When both drivers are staged the tree is ready to be activated. It can be on an autostart system or the starter who's standing between the cars will activate it.

2. Usually but it takes practice to know exactly when to leave but you do leave on the last yellow light to get a good reaction time.

3. Yes. If you break the third beam before the green light is on you get a red light.

Once both drivers are staged the tree will be activated. Unless your track does something different all bracket racing is done on a .500 full tree. This means 3 yellow light come down .5 seconds apart. .5 seconds after the last yellow, the green will be on. There are many variations such as a .4 full tree or like you see on TV, a .4 Pro tree. This is when all 3 yellow lights come on at once then .4 seconds later the green is on. You almost have to anticipate when the yellows come on to get a good reaction time.

In a heads up race or in time trials, reaction times mean nothing except for practice. Once you bracket race you need to figure out your dial in. You ran 16.291. Lets say you got 2 other test passes and ran 16.26 and 16.31. Depending on how much the weather changes you need to guess what your first round will be.

You could put 16.28 on the window. This means you plan on going that fast down the track without going faster. Your opponent will also have a dial in. Lets say he's a full second slower at 17.28. The tree on his side will start 1 second ahead of yours since he expects to be a second slower. Theoretically you will both cross the finish line at the same time. That's why speed means nothing in a bracket race. Anyone can win.

Now he has a 1 second head start but you're both going to finish the same. It's not that simple. Your reaction time now comes into effect. If you cut a perfect .500 light and he was slow with a 1.000 light you now have a .500 second advantage but will never know that until you get a time slip at the end of the race.

The last thing is how close can you run to your dial in. If you slowed down now ran 16.53 and he ran right on his dial, your advantage would be .500 seconds ahead of him because he was so slow off the line.

It's a real numbers game and comes down to inches and thousands of a second. I admit to people that as a drag racer I find bracket racing boring to watch but get behind the wheel and try doing it. It's not as easy as it looks.

Just remember speed means nothing in a bracket race. Make a car consistant and cut a good light. Work on those reaction times. To me anything slower than .550 means I've lost a race but I have also won with .8xx reaction times.

five7kid

iTrader: (14)

"Third beam"? At the starting line?

AlkyIROC

Yes. There are 3. The prestage and stage are the most obvious. If you deep stage you turn off the back beam or more like the tire rolls past it. If you break the third beam before the green light comes on then you get a red light. You can break the third beam while the second stage beam is still lit. That's why a tall front tire gets better reaction times and less red lights. It has a larger diameter and doesn't roll past the beams as easily.

Many people including myself use the 165R15 tires for skinny front tires. They're very short tires, 24-26". Going to a tall MT/Goodyear etc front runner tire which is around 28" tall gets less red lights.

http://www.nhra.com/basics/index.html

87 B4Z

ZZ28ZZ, i was at little river friday night too. what kind of car were you in?

five7kid

iTrader: (14)

I'm operating purely from memory, but I only recall two beams at the starting line at Bandimere.

To quote another page of the referenced NHRA site:

"Two light beams cross the starting-line area and connect to trackside photocells, which are wired to the Christmas Tree and electronic timers in the control tower. When the front tires of a vehicle break the first light beam, called the prestage beam, the pre-stage light on the Christmas Tree indicates that the racer is approximately seven inches from the starting line.

"When the racer rolls forward into the stage beam, the front tires are positioned exactly on the starting line and the stage bulb is lit on the Tree, which indicates that the vehicle is ready to race. When both vehicles are fully staged, the starter will activate the Tree, and each driver will focus on the three large amber lights on his or her side of the Tree."

Two beams, two "staging" lights, three amber lights - I'm not getting where the 3rd beam at the starting line is coming from. Unless there is more than one NHRA system, or IHRA has a different system.

AlkyIROC

It's usually called a guard light. I think the main use of it is so that you don't try rolling to far ahead and past the starting line.

ZZ28ZZ

87 B4Z>>
I was in my Charcoal (gray) 82 Z28.
Didn't get there till abt 9:45 Fri nite.

87 B4Z

i dont remember what time a left, did you see a red IROC there