screw blower belt

Discussion in 'PSI Superchargers Tech Questions' started by skauto, Jan 17, 2014.

  1. skauto

    skauto Member

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    What is the best tooth configuration to run with a screw? 8mm? 11mm? etc... and what is the most common pulley combination to run 92 over say with an 8mm belt?
    Thanks
     
    #1
    skauto, Jan 17, 2014
  2. Mike Canter

    Mike Canter Top Dragster
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    Most use both 8 and 11mm. 11mm seems to last the longest. If you use a Two Step then life is short. 8 mm with a Two Step will get you three runs. 11mm can get you seven.
     
    #2
    Mike Canter, Jan 17, 2014
  3. lucky devil

    lucky devil Member

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    what about 14mm on roots K11 ?
    ​
     
    #3
    lucky devil, Jan 17, 2014
  4. AFC357

    AFC357 New Member

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    Back in my IHRA FC days....we wouldn't push it pas 5 runs...just to be "safe" ...If ya banged a burst panel...change the belt! But this was High OD and RPM
     
    #4
    AFC357, Jan 18, 2014
  5. Blownalky

    Blownalky Top Sportsman

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    Run a 8MM 1600 GT PS 84MM belt. At 92% over and not leaving on the MSD but on an air throttle and the belt will last all year. I figure the extra width is a little stronger over the 75MM and the "Problem Solver (PS)" belt is stronger to boot. Use a 34 top and a 65 bottom so it is actually 91.2% over. The height of the combination will dictate the length and that in combination with the diameter of your idler will let you vary pulley numbers to get to where you need.
     
    #5
    Blownalky, Jan 18, 2014
  6. Soldierboy0098

    Soldierboy0098 Active Member

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    memories

    Ah IHRA, How I miss you. Tim you should come and run with us, its a lot more fun and the same technology.

    Trev

     
    #6
    Soldierboy0098, Jan 18, 2014
  7. Mike Canter

    Mike Canter Top Dragster
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    Back in those days the belts were not as strong and a lot cheaper. On today's NHRA FC you can get 14 runs out of a belt. It is the Two Step with the screw blower that kills the belt. An air throttle is not always the answer either. I don't feel it is as good off the line.
     
    #7
    Mike Canter, Jan 18, 2014
  8. overkill69

    overkill69 Member

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    The two step doesn't kill the belt...it's when the throttle blades are wide open against it. I use the air throttle in conjunction with it and belts are a non issue.
    Mike, have you ever done any back to back testing? On a roots and screw car i've switched back and forth and really saw no change. The screw car was going .99 60ft and I didn't even change the tuneup. 13 lbs of boost vs 35 at the hit and the car ran the same.
    I've researched this quite a bit and all i've gotten is the airthrotttle was abandoned because of consistency.
    The quickest 60ft i've ever seen with a air throttle is .93 on a px car. If that's a performance compromise i'll take it.
     
    #8
    overkill69, Jan 19, 2014

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