water grains

Discussion in 'PSI Superchargers Tech Questions' started by BUTCH, Aug 12, 2014.

  1. BUTCH

    BUTCH Member

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    All,
    last weekend we were running in sonoma CA, we are running a top dragster E.T. was 5.96 to 6.02, the air was pretty good the best was 1400 feet and went up to 2200, My car acted very strange over the weekend so times it would go faster in higher C.A and slow down when air got better, I checked the RH% it was 38% to 64%. and tracked it with B.P. and i just cant get a handle on it, we were off about a .02 on some passes on the e.t. and other times it was dead on.

    also we are tracking the C.A. and make adjustments with in 200 feet to the main jet. the plugs look pretty good maybe 30% to 50 % of the cad is off the face of the plugs,

    we are running a 44 amp mag with a 6 shooter and leah timer, we have adjusted the 60 foot time to 1.0 and it is very stable now, the computer shows that there is not much wheel spin at the hit nor going down the track.


    My question is How to perdict a et on my blown alky dragster, when the water grains change? Or am I just missing something?

    any help would be muchly appreciated

    Thanks again Butch
     
    #1
    BUTCH, Aug 12, 2014
  2. iron468

    iron468 Member

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    #2
    iron468, Aug 23, 2014
  3. Mike Canter

    Mike Canter Top Dragster
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    So what were the Water Grains high and low? Water Grains below 100 normally don't have much effect on the car and normally Water Grains don't swing very fast. Don't get Water a Grains and relative humidity mixed up.
     
    #3
    Mike Canter, Aug 24, 2014
  4. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    top dragster

    I have built and been tuning a screw blown top dragster down here in D4.

    I fought some issues early on with our deal with the car not responding to the air properly. As it turns out, we use an air throttle to leave at part throttle instead of WOT on the two step to save blower belts. I started out with a very small opening - 3/16", and I don't think the air throttle can find that 'spot' consistently against the boost of the blower....the linkage just doesn't have leverage right there. Once I opened it up it got much better.

    Another thing that happens with a Top Dragster that is capable of going quicker than 6.0, is that we usually run them relatively rich compared to a heads up type car. I think that makes them very sensitive to changes in DA. The last time we had the car out, I took the lap top with me to the lanes, ran the air as late as I could get away with, punched it in Jetsize, and I now have jets in .001 increments. I put the exact jet it calls for with as close as I can get the weather. We had an ignition miss end our day at our last race in Norwalk, but we made two runs that were dead on to the thou at 1000'.

    I think any car you dial in you have to watch grains of water and/or humidity more than the DA. Let's not forget wind speed too.

    What kind of weather station?
    Do you monitor head temp?
    Can you post the ET, DA and grains of water for each run to see if there is a pattern.
     
    #4
    Will Hanna, Aug 24, 2014
  5. SoDak

    SoDak Active Member

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    Anyone out there that is also adjusting ignition lead based off of GoW, can you give some educated guess as to how big of a range we are talking? Like is it a 3° change from the driest air to the most humid?

    Also, what is the lowest and highest GoW you've ever seen?

    I've seen 127 GoW for a high
     
    #5
    SoDak, Aug 25, 2014
  6. Blownalky

    Blownalky Top Sportsman

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    I saw 157 GOW at St. Louis this weekend along with 98 degree weather and 4800 feet altitude and didn't have a clue what to do with it as I never saw it that high before, LOL. Obviously, Frankie Taylor and Turkey Al Zafiri (Steve Petty tuning) did as they ran the fastest door car blower and turbo runs in history, a 5.47 @ 263 and 5.46 @ 272 respectively. Those runs were made later at night on Saturday where the DA and OA was better but the GOW was still in the 140's.
     
    #6
    Blownalky, Aug 25, 2014
  7. BUTCH

    BUTCH Member

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    Water grains and et

    Will, All

    Our dragster also has a screw blower and we are also using a air controlled throttle to stage the car, I have the blades set at .125 for staging, and then a 2 step to keep the rpm right where I want the car to stage at, How far open should I adjust the blades for stage?

    I will go through my run data and post the e.t, DA and water grains when I get back to the shop. maybe a week or so work is kind of crazy

    Is there a good hand held weather station that shows water grains ? the one I have does not.

    We also track the left head temp on the motor,


    Thanks again for the help!!!

    Butch
     
    #7
    BUTCH, Aug 26, 2014
  8. Blownalky

    Blownalky Top Sportsman

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    Butch, this is the one I use:

    http://www.altronicsinc.com/racing-...g-weather-stations/performaire-eclipse-1.html

    It's a little pricy but it works pretty good.

    Tom
     
    #8
    Blownalky, Aug 26, 2014
  9. BUTCH

    BUTCH Member

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    Tom

    Thanks
     
    #9
    BUTCH, Aug 26, 2014
  10. SoDak

    SoDak Active Member

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    #10
    SoDak, Aug 26, 2014
  11. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    air throttle

    I would go .250" - at 1/8" the boost at stage wanted to fluctuate from run to run, resulting in inconsistent 60' times.

    I tried to keep the opening minimal to keep it from being too hard on belts. Our car seems to be pretty happy at .250". I don't think the air throttle has enough leverage when the opening is small to find a consistent spot with the blower trying to suck the blades closed.

    We also have the K&R dual air cylinder kit, so that it only goes up on the air throttle once his delay has started. That way it is on the converter the exact same amount of time from run to run instead of the driver having to put the pedal WOT when his side of the tree started.

    In bracket racing, I really think the trailer mounted deal with a pager is the way to go if you can swing it. The weather station is in a constant location and can give you a windspeed number and direction to correlate your runs to.

    I will send you a PM as well.
     
    #11
    Will Hanna, Aug 26, 2014
  12. BUTCH

    BUTCH Member

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    Thanks, Will!!!!!
     
    #12
    BUTCH, Aug 27, 2014
  13. Mark Leigh

    Mark Leigh Member

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    Butch your PM box is full ---------------------------------
     
    #13
    Mark Leigh, Aug 27, 2014
  14. BUTCH

    BUTCH Member

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    Mark, sorry about that, my in box is ready to go

    thanks again

    Butch
     
    #14
    BUTCH, Aug 28, 2014
  15. Blownalky

    Blownalky Top Sportsman

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    My meter has it.
     
    #15
    Blownalky, Aug 28, 2014
  16. SoDak

    SoDak Active Member

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    Do you think it accounts for the moisture in the air or do you adjust for density altitude and then adjust more for humidity?
     
    #16
    SoDak, Aug 28, 2014
  17. Blownalky

    Blownalky Top Sportsman

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    From my understanding in the OA mode, it adjusts accordingly. I just read the altitude, in this case oxygen altitude, and tune from there. I never use the DA feature since I have the O2 feature. My meter does read differently than others I've compared to as it usually reads higher altitude. I just go by it and don't concern myself with the other's readings.
     
    #17
    Blownalky, Aug 28, 2014
  18. SoDak

    SoDak Active Member

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    Do you run blown alky drag racer?
     
    #18
    SoDak, Aug 28, 2014
  19. Blownalky

    Blownalky Top Sportsman

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    Of course, is there anything else, LOL.
     
    #19
    Blownalky, Aug 28, 2014
  20. lucky2wd

    lucky2wd Member

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    YEP........Pulling with blown alky
     
    #20
    lucky2wd, Aug 28, 2014

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