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Technical Blower pulleys size

Discussion in 'The Hokey Ass Message Board' started by Oldfart59, Dec 18, 2020.

  1. Oldfart59
    Joined: Nov 8, 2019
    Posts: 155

    Oldfart59

    Looking for what size of 8mm pulleys to run

    6v92 blower trying to get around 5 to 8 pounds of boost
     

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  2. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 1,678

    Jmountainjr
    ALLIANCE MEMBER

    What application? Most street stuff runs between 10% under driver to 10% over driven relative to crank speed. So you may have to pick a starting point and go from there. Are you sure that's a 6V92 blower?
     
  3. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,038

    Mike VV
    Member
    from SoCal

    Jr.

    You're hooked to the internet...use it...
    One bit of good info I found in about 10 seconds, tooth count, overdrive...and..."approximate" pressure. All right there on one page.
    In another few seconds, I'd bet there are more if you don't like Dyers info.
    But, alas, it's a task that you should be doing..!


    http://dyersblowers.com/pulley_boost_charts.html

    Mike
     
    mad mikey likes this.
  4. Hollywood-East
    Joined: Mar 13, 2008
    Posts: 1,997

    Hollywood-East
    Member

    At a guess I'd say your 15-20 under Driven given pulley size
     

  5. Fordors
    Joined: Sep 22, 2016
    Posts: 5,404

    Fordors
    Member

    The blower in the photo must not be yours, it’s a 4-71. Also, what engine are you building? I think that’s a 250 Chevy is that right?
     
  6. Oldfart59
    Joined: Nov 8, 2019
    Posts: 155

    Oldfart59

    My is a 292 Chevy bored out to a 301

    My blower is a 6v92 blower

    I just don't know what my blower puts out so I would like to be around 5 to 8 pounds of boost
     
  7. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 9,214

    mgtstumpy
    Member

    blower-boost-chart-900.jpg Blowerpulley.jpg
    Charts may assist with pulley sizing to determine over or under drive and boost? Think they're 1/2" pitch
     
    mad mikey likes this.
  8. Who set up the blower? I would think they could tell you what pulleys to use to get what you want.
     
    mgtstumpy and mad mikey like this.
  9. Oldfart59
    Joined: Nov 8, 2019
    Posts: 155

    Oldfart59

    I redid the blower so I don't want to get way to much or no enough

    One guy told me 50 and 55
     
  10. 270ci
    Joined: May 17, 2010
    Posts: 460

    270ci
    Member

    Your 6V92 has the same case ID and rotors as a 6V71 and displaces 338 c.i. per revolution. Your engine uses 301 c.i. in two revolutions.
    Using Dyer's reference charts, you'll want to be 15% underdriven to stay around 8 pounds max boost on your 300 inch motor. Using a 50 on the bottom and a 55 top will only be 9% under. You'll need a 60 top to get closer to 15% under with a 50 tooth bottom, or another combo altogether.
    Post some pics of your set up. Blown sixes are still rare.
     
    Last edited: Dec 19, 2020
    VANDENPLAS likes this.
  11. Oldfart59
    Joined: Nov 8, 2019
    Posts: 155

    Oldfart59

    I will when I get it all together I post pictures when I get it together
     
  12. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,885

    jimmy six
    ALLIANCE MEMBER

    I thought bower guys were like quick change guys... at least 10-15 sets. Hell it’s only money but 9-10 pulleys and play around a lot.
     

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