water grains

Discussion in 'PSI Superchargers Tech Questions' started by blownapex, Jun 4, 2015.

  1. blownapex

    blownapex Member

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    how much timing should be added when water grains increases
    brad fat head automatic c screw promod 10.6:1 128 od
    currently 25 degrees total
    we saw 2500 ft and 107 water grains and the car wouldn't run well
    I keep taking fuel and did get faster but afr is getting close, 4.00 and 4.20 at 9-10,000rpm
     
    #1
    Last edited: Jun 5, 2015
    blownapex, Jun 4, 2015
  2. overkill69

    overkill69 Member

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    fuel

    How many gpm at 8 or 9k in low gear?

    I was surprised to see the 60ft was soft on the run I watched.
    Is that your first outing at 128%?
     
    #2
    overkill69, Jun 5, 2015
  3. blownapex

    blownapex Member

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    flow

    8000=14.39gpm@ 52 psi @2500ft and 107 water grains
    60ft, 1.01, .998, added timing down low took fuel out .938 , then .938
    sunday was 500 ft air and 50 watergrains flow at 8000= 15.62 didn't make it past 1 second
     
    #3
    blownapex, Jun 5, 2015
  4. Mike Canter

    Mike Canter Top Dragster
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    So with a 500ft DA did your wheel speed go too high and put you in a high speed shake?
     
    #4
    Mike Canter, Jun 5, 2015
  5. blownapex

    blownapex Member

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    watergrains/wheelspeed

    yes to much wheel speed at 1.00 seconds
    I needed less at .80 to 1.20 probably but really needed more in 60 ft and after the shift
    more timing may have fixed the 2500 ft /107wg but it would have to be lowered on the 500 ft day

    any suggestions on adding timing
    like 50-60 wg add .5 degree
    60-70 wg add .5 degree
    1/2 degree for every 10 wg
    1/2 degree for every 20 wg
    or forget timing and just keep leaning when water grains are high

    davenport keeps the engine happy but doesn't get your power you lost back, in bad air

    thanks mike we don't have our buddy bill barrett to help anymore (rip)
     
    #5
    blownapex, Jun 5, 2015
  6. Mike Canter

    Mike Canter Top Dragster
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    That amount of change in weather and your car's performance indicates that you need a transmission gear change.

    Yes. RIP Dr Bill Barrett
     
    #6
    Mike Canter, Jun 5, 2015
  7. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    jet

    i stick with the alky pro or jetsize recommendation, but I do know some tuners have told me they use a formula to lean or richen the main jet based on grains. If your baseline run was at 70 grains, they would lean/richen it 2 per every 10 grains of water plus or minus.

    Now before anyone goes leaning on their stuff, I don't know exactly what they were using to come up with a main jet and how much their method accounted for grains.

    I do push my tuning modifier a little more when it's humid. That is the same concept.
     
    #7
    Will Hanna, Jun 9, 2015

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