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Old 07-02-2007, 11:22 AM   #1
Dustin Chase
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Default Dedenbear T Stop Timer

Up until recently we were running a dedenbear tumbler style timer, and Number One stop electric Throttle stop. It seems that when we go to 2.9 or more in the box the car would fall way off. In the afternoon in medocre air we would have 2.70 to 2.80 in the box and run damn near right on 10.90. Then the good air comes and I need to go from something like 2.88 to 2.92 or so and the car would fall off to an 11.20 or so. This happens every time. Since super street is usually first or second on the track in the best air of the day we would try like 3.00 and run damn close out of the box. Second Time trial little worse air need 2.9 something in the box and fall way off. JUst for giggles the next pass try 2.89 and run just under the index but too far to chance it. My dad doesn't lift well he likes to run it out. Sorry so wordy just wondering if anyone else has heard of a bad tmbler in these boxes. We now have a biondo mega 450 in the car just waiting to go try it.
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Old 07-03-2007, 07:27 PM   #2
Mike Hedger
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Default Re: Dedenbear T Stop Timer

First you need to know your throttle stop ratio, IE is it 2 to 1 (you change from 2.50 to 2.48 and pick up .01 on the track) The old timer you had was prob. OK as these were just about indestructable. You will throw it in the trash after using the 450 as it is a great piece. Next what does the DA do to your car on gas a good rule of thumb is for every 200 feet of DA change it usually changes .01 on the track so using these numbers if you ran a 10.86 at 1800 feet of DA and you were to run again at 2000 feet of DA you need to compensate for -200 feet so it will slow you .01 or 10.87 then add the 6 numbers for the rest of the .03 you need to slow down.

After you know these numbers you can do your own math and just use your prediction to double check your math.

Double check your soll. on the T stop and keep it lubed also make sure you have a good strong 12V to it. Hope this helps, Mik eHedger S/C Q/R 4600
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Old 07-03-2007, 08:22 PM   #3
Dustin Chase
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Default Re: Dedenbear T Stop Timer

We have all of that figured out as far as what the car does with the change in DA. Everything works perfectly until I put 2.9 something in the box. then goes back to working when I put 3.00 or 2.8 something in. For instance. Texas Motorplex. 800 feet DA 9:00 in tha morning, 3.00 in the box. 10.94. Next time trial 1000 feet DA 2.95 in the box. 11.21 with a lost of 10 MPH Next Time trial. at 4pm 1800 feet DA 2.88 in the box 10.89 . There is something going on with the box. At belle rose I can stay between 3.00 and 3.20 and run 10.90 all weekend. until first round at 8 in the morning before the humidity gets up the prediction shows 2.96 we put 2.95 to get there first but run an 11. something. Doesnt really matter unless the mega 450 does it too.

thanks
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Old 07-03-2007, 09:04 PM   #4
Rick4310
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Default Re: Dedenbear T Stop Timer

How fast is the car? What does it run wide open?
thats alot of time in the timer,
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Old 07-03-2007, 10:11 PM   #5
Mike Hedger
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Default Re: Dedenbear T Stop Timer

Have you made a blade angle change to the t stop and tried to get away from the 3.0 range to see if it is predictable? I would try two more turns under the carb (12 rounds to 14 for ex) and see if you can get to 2.5 sec and see if it still does it. It sounds like the .9 # is the faulty digit/timer. You will love the 450 and all it has to offer. one box does everything and then some. Hope this helps, Mike
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Old 07-04-2007, 01:15 PM   #6
Dustin Chase
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Default Re: Dedenbear T Stop Timer

We have not run the car wide open with this motor. We run the throttle stop at 15 turns in I believe. We are killing it a bunch and its a big car. We also don't kill it until .50 into the run. Like I said this is a big car and we want to get a good launch and 60 foot.
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Old 07-04-2007, 02:01 PM   #7
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Default Re: Dedenbear T Stop Timer

When I had my S/St car I killed it at .002 to try to kill the wheelstands, and it got the 60' to repeat quite a bit better, Remember the sooner you kill it and get it back wide open the more MPH you will run. (My chevy 2 ran 10.90 at 144) you will also have less time in the timer witch will make the car more predictable. Try it you might like it. Mike
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Old 07-05-2007, 06:56 PM   #8
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Default Re: Dedenbear T Stop Timer

This is a 3300 lb car but i think we will start at .010 in the stop and see what happens. Thanks for your replys guys
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Old 07-07-2007, 08:49 PM   #9
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Default Re: Dedenbear T Stop Timer

Dustin

do you know what the RPM on the stop is? Do you shift on time or RPM.I have found that between 3900 and 4200 rpm's on the stop is optimal. If you have too high of stop rpm the car can accelerate while on the stop and get close to the shift point RPM if the car jumps off the stop and goes directly into high gear you will LOSE a bunch of ET. Sometimes the car will even shift while on the stop. (even worse). If the stop rpm is too low the boosters in the carburator will float and dump fuel (not good)

If you dont know how to check the Stop stall here is what you do.
1) pull the launch chip from the 2step
2) engage the stop (pull the lines off the air feed) so the stop blades are closed
3) start the car and put it in first gear
4) press the trans brake button
5) mat the gas and watch the tach (for about 1-2 sec)
that is your stop stall within 100-200 rpm

Check it out & let us know
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