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Discussion Starter #1
Next Friday I'm going to get my 66 Chevelle to a rent a track day. My converter stall is 6500 but I don't know where the max tq is. I'm racing pro light so do I set the 2 step close to the 6500 or back it down to about 5500-5800?
 

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Next Friday I'm going to get my 66 Chevelle to a rent a track day. My converter stall is 6500 but I don't know where the max tq is. I'm racing pro light so do I set the 2 step close to the 6500 or back it down to about 5500-5800?
I have about the same stall in my truck. 2-step is at 5,000 and works great. The instant I let go of the trans brake button my tach jumps to 6500+
 

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Discussion Starter #4 (Edited)
Thank you. Both posts were helpful but leaves a couple questions:

If leaving on a 5000 chip on a 6500 stall, will hitting the converter harder quicken my ET?
Leaving closer will quicken the reaction time but not hit the converter as hard. Will hitting the converter less, say 6000, slow the ET but make the time up in reaction time?

I getting close to my 5.50 dial with a 5.62 best but with a little tuning, weight lose and shift point change I'm hoping to get much closer to 5.50 NA.
 

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To many variables to give a concrete answer but basically try 3000-6000 and see what the car holds and what gives the best reaction time and 60 ft. There is no correct answer in my opinion because all cars are different then throw in the driver variable.
 

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Ours stalls at 6300-6500 and at 2640lbs pro tree leave at 4200, bottom bulb 3600 1.39x 60ft 9.7x and 6.2x. 500 or 400 tree? our is on a .500 tree,with some in the box, if on a .400 go high and use the box to get where you need.
 

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Next Friday I'm going to get my 66 Chevelle to a rent a track day. My converter stall is 6500 but I don't know where the max tq is. I'm racing pro light so do I set the 2 step close to the 6500 or back it down to about 5500-5800?
5100-5200 rpm leave.
 

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To many variables to give a concrete answer but basically try 3000-6000 and see what the car holds and what gives the best reaction time and 60 ft. There is no correct answer in my opinion because all cars are different then throw in the driver variable.
Agreed!! You got to figure it out in testing. Start at 3000. Make 500 rpm incremental changes and see what happens.
 

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I have done a lot of experimenting with this. A lot depends on your power level. If your car is capable of 9 second et's and has small fronts, you can chip down quite a bit and gain consistency. If you have a slower car and need everything it has to get it moving, you may end up only 500 rpm below stall. I have about 600 hp and stall 6500. I leave at 5600 regularly for a pro tree.
 

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Ours stalls at 6300-6500 and at 2640lbs pro tree leave at 4200, bottom bulb 3600 1.39x 60ft 9.7x and 6.2x. 500 or 400 tree?
our is on a .500 tree,with some in the box, if on a .400 go high and use the box to get where you need.

I'm like you, I have a bigger spread than most and it seems to work fine, 1.05-1.06 60'.
6900 stall with a 4500 chip at 2595 lbs.

.
 

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Discussion Starter #11
I was hoping not to beat the car up testing from 3000-6000 2 step for a pro tree. It's a 3150 lb big tire car with about 940 hp but not on a dyno. Fastest 60 ft was 1.27 and fastest 1/8th was 5.62. I know I need to be close to a 1.22 60 ft and 3.50 330 ft to get close to 5.50. The class I'm trying to run is 5.50 and 5.62 won't be competitive. The density altitude is 3000 and higher most race days except very early in the year.

I have two full size Yellow Tops in the car and I have a smaller Yellow Top that weighs 19 lbs. The larger ones weighs 34 lbs. I do have an alternator and I was thinking about putting just the 19 lb battery in just for the 5.50 class racing.

I don't want to beat the car up and reaction time is important, so that's why I was hoping to get an opinion on whether or not my ET would be quicker hitting the stall lower like 4000-5000 or if the ET would be quicker leaving at 6000 on a 6500 stall. My 5.62 run was leaving at 5600 rpms.
 

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If you already know it likes the 5600, stick with 5000-5600 depending on traction.
Definitely pull the big battery and any other weight you can find, then go on Atkins and you're there, 5.50's :D

Good luck & race safe!!!

.
 

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Discussion Starter #13
Many of my racing friends also told me to lose about 50 lbs:):( and I lost 10 lbs already, but it's hard.

My question though is hitting/flash the stall from say 5000 going to plant the tires harder and quicken the 60 ft or is the 6000 rpm only hitting the 6500 stall going to give me a quicker 60 ft. I'll try it next Friday, just wanting other racers experience/advice before next Friday?
 

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with my heap (7.70-7.80 1/4 mi) if i chip it down and give it a run up to flash, the car will always 60' faster. Im 5500 on the chip, and it flashes to 7 ish. I havent tried lower, as even at the 5500 ish its pretty hard leaving (1.09-1.10 60'), so i dont push my luck.



When i pro tree (supergas) i chip it up to 6300-6400 to try to get the reaction time down. I dont really care about the 60 being good on the stop.
 

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My small block dragster stalls around the same, 6500rpm, but I get the best 60ft and no tyre shake getting a run up at it from 3200rpm. 7.60 car.
 

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Mine doesn't like that low with the tunnel ram. Yours must be dialed in really well yo run that low on the brake.

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The trans guy who freshens my trans told me to try it at 5000rpm, but it would shake the tires out past 60ft like a ProMod. It was literally breaking parts on the car and giving me a headache. Dropped it back and gave it the run up and it pulls the fronts a foot off the ground. It's done a 1.04 60ft. Not too bad for a cheap bracket small block.
 

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Discussion Starter #18
With a tunnel ram and two small 1050 Dominators it might be hard to burn the fast enough if I lower the 2 step too far. I'm sure I have some tuning to do as well while working with launch RPM.

Thank you for the responses. I'm going to work through them next Friday. I'll try 5500 go up to 6000 and then to 5000 and go from there.
 

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400 pro tree 3250 pds 10 x 28 tire 1/4 mile 10.0 index

6300 180 low, 4.10 gear leaving 4600.



370 Pro Tree 3250pds 10 x 28 tire 1/8 mile 6.50 index

6200 stall converter 1.69 low , 4.88 leaving 4700

 

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There are a lot of variables in cutting a good light with a .400 tree. I have found going to the track a practicing is the best thing. I was told the converter should be 300 rpm higher then peak torque. You want to draw the motor down to its wheel house. Depending on what track you are at you may need to move the leave rpm down. My peak torque is at 6200 so my converter flashes to 6500. I leave at 5200 on a good track and will always go better then a .020 every time on a .400 pro tree. but here has been tracks I backed it down to 4500 and still cut a good light. Practice is the best thing. I also run 5.50 index N/A.
 
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