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Discussion Starter #1
How do I launch with my TQ converter? My stall converter is a TCI Street Fighter. Supposed to have a stall speed of 3000-3500. Last time I was at the drags, I brought it up to 3,000 RPMs, and walked into it. Was I right, or wrong? Help me guys


Jeff Given
 

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Here is the classic answer: That depends. Did the car do what you wanted with that technique? Are you concerned with reaction times, or just elapsed times? Typically, the harder you can flash a torque converter on launch, the more torque it will deliver. If you have the traction for it, then you will ET better. Example: stage at the lowest rpm that the engine will still respond well to mashing the gas, say 1500 rpm, and the converter can flash up to 3500 rpm (or whatever the power balance point is). This will be a higher flash rpm than if you stage with your foot already to the floor or very close. Let's say you can only hold the car back by staging no higher than 3000 rpm. When you mash the gas it may only flash to 3200 rpm, thus a net loss of torque multiplication in the torque converter relative to the previous method. However, what you give up in peak launch power, you get back in reaction time. The higher rpm you stage at, the sooner the car will move once you let go of the brake and mash the pedal down. This isn't because the power is higher, it has to do with the amount of time it takes to 'spool up' the rpm if you stage at a low rpm relative to your peak stall point. It will obviously take more time for the engine to accelerate to the stall rpm if it has to climb by 2000 rpm instead of 200 rpm. Also, it flashes higher when staged at a low rpm because of the momentum effect. There is no momentum effect when staged close to the stall rpm of the converter. You may not notice a significant difference in ET's based on what your stage rpm is, unless tire spin is involved, but you will notice a big difference in reaction times. Competent bracket racers can 'tune' their reaction times by altering their stage rpms, and experience tells them how much effect this will have on their ET, if any.

A bit long winded, but helpful maybe?
 

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Discussion Starter #3
Bartholomew:

Yes, I am sure that was helpful to someone that knows more then I. However, I dont know too much, and this TQ Converter is making stuff even worse. So no it did not really help me, because I did not understand it. Can it be broken up any more then that, or am I just a lost soul?? Thanks a lot Bartholomew


Jeff Given
 

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Stalling lower and getting a "bigger run" at the convertor doesnt always give better et's even when good traction is present. It sounds good in theory, but in my case it works the opposite. My car runs faster the higher I 2-step it. As does my buddy's bbc nova. Both cars act the same. Turn the 2-step down, they slow down, turn it up, they go faster. Thar's how we "tune" for track conditions, if the track isnt real good, we lower the launch rpm to take some hit out of the tires.

I have generally found, the higher the rpm you can hold the car on the line, and if enuff traction is present to handle it, the car will et better.

<font size=-1>[ This Message was edited by: kid vishus on 2/5/02 10:45pm ]</font>
 

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The above posts are right most of the time. Usually the only time you want to leave from just off idle and flash the converter is if you're having traction problems. When the torque converter is loaded against the brakes it tends to pre-load the suspension and use up some of reaction and travel that the suspension normally goes through when launching. By leaving off idle the suspension gets shocked and reacts more violently, driving the tires into the pavement harder, often helping the car to hook better. So very basically, keep raising your launch RPM until you start having traction problems and then just back it off a bit. Make sense?
 

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Jeff, I hoped I wasn't getting too deep. Sorry. What do you mean by this torque converter is making things worse? Describe your situation, before and after, and what the problem is, please. Then I (we all) might be able to help.
 

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Discussion Starter #8
Making it worse...what I meant was I dont know much, and this is not helping my knowlede any
THANKS A LOT!

Jeff Given
 

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Ok Jeff, how you run your car at the track becomes trial and error. Try staging at different rpms and see what happens. Some cars like being staged at high rpms and some don't. There is no 'wrong' way to stage your car unless it gives you a bad result. Have fun at the drags......
 

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Discussion Starter #10
Ok, thanks a lot! I think I will take a notebook next time, and create a journal. That would definately be good for me. My memory is short like...a mushroom. Thanks!

Jeff Given
 
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