Auto shifter venting excess co2 help

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Soldierboy0098, Jul 5, 2017.

  1. Soldierboy0098

    Soldierboy0098 Active Member

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    Hi,

    Here is my dilemma and I am hoping someone can help me out. I use a power grid, Leahy auto shifter (Air controller) and a 3 spd. I have my car set so that when I press and hold the burnout button it puts air into both pods on the trans putting it in high gear I believe and when I hit the trans brake button it puts the car into low gear by venting the air in the auto shifter. I do this so no mistakes can be made and there are no switches to remember however, the only down side is when I am on the transbrake at the starting line it is venting air. The air vent orifice in the Leahy Autoshifter is very small but I am unsure if too much co2 will be venting and am unsure if anything can be installed such as an old logic timer to limit the amount of bleed time, it only needs to bleed the air long enough to get the trans back in low gear which I believe is done by letting the air out of the trans.

    Any thoughts on this?

    Thanks,
    Trevor Sherwood
    727-364-4368
     
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  2. Blownalky

    Blownalky Top Sportsman

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    If you are going this route with an auto shift, buy an ACD shift control as it will take care of all of this. Very simple to use and very reliable.
     
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  3. Soldierboy0098

    Soldierboy0098 Active Member

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    Hi, The irony is the car had one in it and I sold it because I had never used one before and wanted to do everything with the grid for the sake of weight. It was one less box and lots of wiring from what I removed. I think I may just put the vents on a momentary switch. It's one more thing I need to remember but after talking with a friend who likes to back up in high gear and given that most other cars have the momentary switch so I may as well just get used to it. This may actually simplify things in regards to how many relays and how much wiring I need as well. Going to draw it up tomorrow and see what I can come up with. Out of curiosity what all does that ACD unit do?
     
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  4. hydrotherapy

    hydrotherapy Member

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    They make a dump valve that you put in line both air pod lines amd as soon as it senses a presure drop it releases all air in the line.Call Scott Owens at Owens transmission he sell them ,and they work perfect ,we use it on our acd shifter, and have it hocked up to our air line to the parachutes so when he pops the chutes it puts the lencodrive in low gear and does come down on the motor.
    Owens Transmissiom
    559 539 3935
     
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  5. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    Is the bleed on that solenoid hooked to the pressure side?

    Once the signal lines to the pods are dumped, there should be no pressure to bleed right?

    If you hold the button down does it constantly bleed at the same rate?
     
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  6. Soldierboy0098

    Soldierboy0098 Active Member

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    What It is is an H shaped deal with 4 solenoids (2 on each side) and an air log in the middle. 2 on the same side are for letting air through (Shifting) and 2 are on the other side for letting air out/Venting. I have it so that when I press the burn out button it activates both shift solenoids and then when I have the transbrake pressed it opens both vent solenoids. You may be onto something Will, I haven't tested it yet as the car was out of co2 but it may just vent the shift chambers instead of the log. I will rig it up this weekend and do some testing. I guess if it doesn't then no worries and I just need to decide if I want to back up in high gear or low gear and then figure that out. I will let you know as soon as I test it.

    Thanks,
    Trev
     
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  7. Soldierboy0098

    Soldierboy0098 Active Member

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    As soon as I do some testing here this weekend I may go down this road. Thanks -Trev
     
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  8. hydrotherapy

    hydrotherapy Member

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    Back to the dump valves the vent in the soleniods is to small and when the dump valve sees a presure drop it has a 1/4 " vent and releases all air in the pods and in the lines ,we been using them on Owens trans for years
     
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  9. Soldierboy0098

    Soldierboy0098 Active Member

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    Will Hanna gets 5 points and I lose 3. So I rigged this back up on my dragster which is where I tested this thing over a year ago and the hissing I heard was from a small cut in the push to connect line right at the fitting, as I had no help on that day I couldn't find any leaks and assumed it was the vents as it only did it on the button. Had I thought it through I would have realized it would make no sense to dump the air log because it would just keep filling with air from the bottle. So it works perfectly the way I have it set up if I want to back up in low gear. Not sure what peoples preferences are on backing up a roots pro mod but the shifter issue is not an issue. Thanks ITA and Will Hanna!
     
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  10. Soldierboy0098

    Soldierboy0098 Active Member

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    I just deciphered my wiring from 2 years ago and as an added bonus I just realized the way I am doing it you can back up in high gear if you want just by bumping the burnout button again after you get it into reverse...No re wiring for me other than to pretty up my initial job :) and best of all I just have one switch to turn on after I get the car backed up and into forward so all of my timers will start. Hazaa!
     
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  11. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    As a crew chief I'm not a fan of the driver hauling ass backing up. Driver may think it's cool, but a lot of bad things can happen as the steering/suspension is not set up to back up. Also it is a little harder on the reverser backing up in high if you have the old style B&J reverser or Lenco.
     
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  12. Soldierboy0098

    Soldierboy0098 Active Member

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    I am not looking to back up fast, slow and controlled for safety is my way. I was just told given our odd combo the car may not be able to stop in low gear when backing up and that although you are on the brakes a little more in high gear it may be more controlled. The best thing is now I can try it in low first and if there is an issue I just bump the button and Viola High gear again.

    Thanks Will,
    Trev
     
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