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low speed rpm launch #1524858
10/28/13 09:39 PM
10/28/13 09:39 PM
Joined: Oct 2011
Posts: 3,036
bean town ....Ca
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WHITEDART Offline OP
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WHITEDART  Offline OP
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Joined: Oct 2011
Posts: 3,036
bean town ....Ca
I im trying to help a friend that is currently foot braking his car. we would like to launch off the line lock @ 1800-2000 rpm. this car is using a msd 6al box. I have not seen any chips that are less than 3000 rpm... any body have a good ideas thanks


In the 8s N/A.with Brett miller W8's
5.07 at 133 at 2700lb
Re: low speed rpm launch [Re: WHITEDART] #1524859
10/28/13 09:51 PM
10/28/13 09:51 PM
Joined: Jan 2003
Posts: 4,267
Morrow, OH
markz528 Offline
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markz528  Offline
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Posts: 4,267
Morrow, OH
Uses standard MSD chips - right?

If so, just use a 1.5k ohm pot. Go to radio shack or wherever and get a 1500 ohm potentiometer. Center tap to either one of the other tabs and you are good to go.

I would need to look better at my data, but I believe 1800 rpm would be around 650 ohms and 2000 rpm would be around 860 ohms.

You can also use regular resistors.

For my leave point, I use a modified potentiometer and use a 10 turn pot with a locking dial. I just look up the rpm I want on my spread sheet and set the dial and I'm pretty close.


67 Coronet 500 9.610 @ 139.20 mph
67 Coronet 500 (street car) 14.82 @ 94 mph
69 GTX (clone) - build in progress......
Re: low speed rpm launch [Re: markz528] #1524860
10/28/13 10:06 PM
10/28/13 10:06 PM
Joined: Jul 2004
Posts: 653
Fredericksburg Va
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plycuda Offline
mopar
plycuda  Offline
mopar
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Joined: Jul 2004
Posts: 653
Fredericksburg Va
MSD Ignition 8677 a chip you adjust with a small screw driver from 1k to 3k

Re: low speed rpm launch [Re: markz528] #1524861
10/28/13 10:06 PM
10/28/13 10:06 PM
Joined: Jan 2003
Posts: 9,826
las vegas
70AARcuda Offline
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Posts: 9,826
las vegas


Tony

70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
Re: low speed rpm launch [Re: markz528] #1524862
10/28/13 10:07 PM
10/28/13 10:07 PM
Joined: Nov 2003
Posts: 7,348
Mt.Vernon ,Ohio
VernMotor Offline
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VernMotor  Offline
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Posts: 7,348
Mt.Vernon ,Ohio

Re: low speed rpm launch [Re: markz528] #1524863
10/29/13 01:19 AM
10/29/13 01:19 AM
Joined: Feb 2007
Posts: 1,608
fresno ca
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mikeysmopars Offline
top fuel
mikeysmopars  Offline
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Joined: Feb 2007
Posts: 1,608
fresno ca
Quote:

Uses standard MSD chips - right?

If so, just use a 1.5k ohm pot. Go to radio shack or wherever and get a 1500 ohm potentiometer. Center tap to either one of the other tabs and you are good to go.

I would need to look better at my data, but I believe 1800 rpm would be around 650 ohms and 2000 rpm would be around 860 ohms.

You can also use regular resistors.



For my leave point, I use a modified potentiometer and use a 10 turn pot with a locking dial. I just look up the rpm I want on my spread sheet and set the dial and I'm pretty close.







I need him on my pit crew!


Founder and CEO of the Central Valley Mopar Drag Pack
Re: low speed rpm launch [Re: mikeysmopars] #1524864
10/29/13 03:09 AM
10/29/13 03:09 AM
Joined: Jan 2003
Posts: 3,830
N.E. Ohio
6bblFLASH Offline
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6bblFLASH  Offline
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Posts: 3,830
N.E. Ohio
As stated ,the adjustable MSD chip is what I used when I used a transbrake to run the wheelie thing at the nationals one year.

Word of CAUTION
If you are`nt running enough octane combined with that low RPM limiter it will beat your engine to death.
I have a set of pistons with the top ring lands that look like wafer-springs .
Car started running slower as soon as I started using a 2-step and brake.
Assumed it did`nt like the brake WRONG 2-step caused detonation against the converter


70` Cuda`,440 6BBL Jerico,Dana 4.56 Still on 93 Pump Gas
9.87 @ 136/1.31-60ft.`09 Mopar Nationals PASSON PERFORMANCE "Stick-Shift" Champ!
2013 StickShift Challenge Winner@ Mopar Nationals!
Re: low speed rpm launch [Re: 6bblFLASH] #1524865
10/30/13 03:34 PM
10/30/13 03:34 PM
Joined: Jan 2004
Posts: 8,193
fredericksburg,va
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cudaman1969 Offline
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cudaman1969  Offline
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Joined: Jan 2004
Posts: 8,193
fredericksburg,va
I used the air activated throttle. Push button pedal goes to floor to a set rpm, release button and air pulls throttle open, no stuttering very consistent. Can be run with box or off last light.







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