inproving reaction time on a footbrake launch

Old 08-25-2009, 03:32 PM
  #1  
chevysteve2
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Default inproving reaction time on a footbrake launch

I have a street/strip 67 camaro, 28" drag raidals and caltracs with 2 flats of preload. I have been running brackets with but I need some help non shaving time off my reaction time. I launch with the foot brake barely off a idle. I have practiced on a practice tree and have reaction times from .01 and .05. But in the real world it is .7 to .16, which won't win too many races. I wanted to experimint with stageing deeper. I usually bump in very slow just enough to light the second bulb. my question is about how much futher could I go before I risk turning the prestage light off. Is it about the same distance from when I light the prestage light to when I light the staged light. Also will this help my reaction time by stageing deeper. my tires are 26 inches tall in the front. My car runs very consistant but I have too dial soft,and end up on the brakes before the end of the quarter to make up for my reaction time. Everone tells me to put in a transbrake and call it a day, but my car is very heavy at 3500 because of the full interior, and I dont want to start breaking parts, as I can barely afford the entrie fees, fuel, and other costs associated with racing.
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Old 08-25-2009, 04:51 PM
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zipper06
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IMO, you just said what the problem is. You're barely above idle, that means that once you release the brake and nail the gas, your car has to wind up and shock the tires to move forward. the best way to leave on the foot brake is have the car preloaded, with as much as you can hold with the brakes, this way the car is already to leave when you release the brake.

JMO

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Old 08-25-2009, 05:12 PM
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fla1976
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Default reaction time.

X2 on that. Preload and see what it does.
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Old 08-25-2009, 07:56 PM
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chevysteve2
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I will try that. Do you think I should install a launch control (MSD 2 step) or just bring it up on the converter a little while holing the brake.

thanks for response
steve





Originally Posted by zipper06
IMO, you just said what the problem is. You're barely above idle, that means that once you release the brake and nail the gas, your car has to wind up and shock the tires to move forward. the best way to leave on the foot brake is have the car preloaded, with as much as you can hold with the brakes, this way the car is already to leave when you release the brake.

JMO

Zip.
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Old 08-26-2009, 03:02 AM
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slowmotion
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I'd just start with raising the RPM a few hundred and see what happens. Vary it to see how the car responds and find the "sweet spot" that works for you and the car. I wouldn't go full tilt agains the converter. If you stage first and the other guy hears you up high in RPM's it gives him the chance to burn you down. If you are bracket racing and you are the faster car, you might be there awhile. I don't know about footbraking but on a 2 step a converter builds 100 degrees a second.

Something else you said was that you dial the car to compensate for your lights. One has nothing to do with the other. You can sit on the line for 30 sec and still run the same ET.

What pressere are you running in your front tires? Higher pressure equals lower RT's. I had a 17 sec street car that 1lb in the front tires was about .01 on the tree.

IMO if you want to be consistant when you go deep, you have to bump in until you turn off the prestage light . The problem is some tracks may not allow it and at some tracks it's your responsibility to get in there 1st and be ready. If somebody quick trees you, you might be trying to bump in when the trees starts coming down.
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Old 08-26-2009, 10:18 PM
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chevysteve2
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I think I will just try to bump in the same way I always do, because you are right about someone comming in quick on the tree and it falling before you are ready. also if I turn off the prestage light it is a foul in my class. I run 35 psi in the front. I will try 45 and see if that makes a difference.

the reason I asked about the two step is I have heard about people putting the button on their left top corner of their brake pedal. when they are at the light they just raise the rpm until the engine slightly studders. I guess what I am trying to accomplish is to leave at the same rpm each launch without having to glance at both the tree and tach.

For now I will pay much more attention to listening to the motor at the light. I guess it will be like down track when the shift light goes on I already have pressure on the shifter anticipating the light by listening to the motor. once again thanks for the advice you guys have been helpful.

steve





Originally Posted by slowmotion
I'd just start with raising the RPM a few hundred and see what happens. Vary it to see how the car responds and find the "sweet spot" that works for you and the car. I wouldn't go full tilt agains the converter. If you stage first and the other guy hears you up high in RPM's it gives him the chance to burn you down. If you are bracket racing and you are the faster car, you might be there awhile. I don't know about footbraking but on a 2 step a converter builds 100 degrees a second.

Something else you said was that you dial the car to compensate for your lights. One has nothing to do with the other. You can sit on the line for 30 sec and still run the same ET.

What pressere are you running in your front tires? Higher pressure equals lower RT's. I had a 17 sec street car that 1lb in the front tires was about .01 on the tree.

IMO if you want to be consistant when you go deep, you have to bump in until you turn off the prestage light . The problem is some tracks may not allow it and at some tracks it's your responsibility to get in there 1st and be ready. If somebody quick trees you, you might be trying to bump in when the trees starts coming down.
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Old 08-28-2009, 10:34 PM
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chevyfireball
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Your R/T has nothing to do with your final ET. The timers don't start until you trip the beam. If you're having to brake at the top end you might wanna change your dial in.
Like your friends say, put in a transbrake and be done with it. You'll never go back to footbraking.
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Old 08-29-2009, 06:38 AM
  #8  
ashbros
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Transbrake X2


You will wonder why it took you so long to step up to a trans brake. Its a whole new world...
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Old 08-29-2009, 08:07 AM
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TheRabbit
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Transbrake X 3. Even with a transbrake you don't have to leave hard. Put a 2 step on it and leave at whatever RPM you want. I'm 3,600 and leave at 5,000, but you have to have a pro gear to handle it. My 60' times are 1.3's, so I'm hooking just as hard as you pavement pounders! :lol:
You could also put a throttle control on it.
We run a Consistency class. Kinda like a bracket class, but you only run against a clock. In other words you try to run the same time twice. You'd be supprised how often somebody runs an excact time .000. (Reaction time not included)
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Old 09-04-2009, 03:24 AM
  #10  
CamBirdRacing
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I don't bump in. How do you know if you are going in the same everytime? I just adjust where I leave on the tree. I shallow stage everytime, except when the brakes don't hold, haha.

What ever you try, do it the same for hte shole night you are there, then change your style the next time you go out. And try that one all night long.
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