blower output in cu in

Discussion in 'InsideTopAlcohol.com Tech Questions' started by 3-D, Apr 15, 2009.

  1. 3-D

    3-D Member

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    I have a Kobelco 8-71 Superman and need to know the cubic inches per revolution. Can anyone help me with that?

    thanks
     
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  2. GregM784

    GregM784 Member

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    A theoretical 500CFM
     
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  3. 3-D

    3-D Member

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    you state cfm, what about cubic inches per revolution
     
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  4. TOL

    TOL Active Member

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    If I'm not mistaken, I think the blower size/name says it all. 8 times 71 equals 568 cubic inches. That is only the theoretical displacement, at zero gage outlet boost pressure, ignoring all other factors which would serve to reduce that number. In other words, if you were to slowly turn the snout one revolution by hand, you would theoretically move 568 cubic inches of free air from one side of the case to the other.
     
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  5. secondwindracing

    secondwindracing top alcohol

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  6. Mike Canter

    Mike Canter Top Dragster
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    I don't think that is correct because of different shape rotors. I know that a 14-71 SSI B Rotor moves 625 cubic feet in one revolution.
     
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  7. Chuck Stevens

    Chuck Stevens New Member

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    ? Cubic feet???
     
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  8. tafccrewguy

    tafccrewguy New Member

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    Fuel Injection Enterprises lists an 8-71 at 436 and 500 for a high helix 8-71.Thats off the tune up calculator.
     
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  9. craig moss

    craig moss Member

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    I totally agree well put!!:cool The diesel they originated from made very little boost if any. Their main purpose was to scavenge the exhaust out of the cylinder on a 2 stroke Detroit diesel(theoretical displacement) would be an accurate term
     
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  10. 560Jim

    560Jim Member

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    My understanding of the original blower sizings was that a 6-71 came off a detroit desiel of 6 cylinders at 71 ci per cylinder. I dont believe it has anything to do with blower volume or output.
     
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  11. thjts

    thjts New Member

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    'Blowers'

    Absolutely. That's how there are 4-53s, 6-71s, 8-92s, 8V-71s, 6V-92s, etc. I believe these were never bigger than an '8', as the biggest engine block Detroit (the diesel engine manufacturer) made came in an '8V' (Bigger engines were simply two appropriate blocks bolted together), so the biggest 'blower' was an 8.

    71 series engines are very common, so 71 series blowers are very common as well. Since everyone was using 71 series blowers, this became the defacto standard by which blowers were sized for 10-71s, 12-71s, 14-71s, etc.

    Craig Moss is also right. Their nickname of 'blower' comes from the fact that they were originally used to 'blow' (scavenge) the exhaust gases out of 2-stroke diesel engines. They were driven directly off the camshaft at camshaft speed, hence the low output pressure. Very early ones couldn't be turned fast because they simply weren't designed for high speed and would explode if you did.

    High horsepower 2-stroke diesels actually use a hairdryer to produce boost, they don't speed up the 'blower'.
     
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    Last edited: Apr 16, 2009
  12. Mike Canter

    Mike Canter Top Dragster
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    Actually a scavenger blower on a two cycle diesel was on the exhaust side of the motor and scavenged or sucked the exhaust out which in turn draws more air in. These blowers were commonly used in the diesels on older US submarines and in trains (they used the same diesels). These big diesels had 8, 10, even 12 inline cylinders and V-16 cylinder arrangements. The most common were made by Fairbanks Morse and less by GM. When I was in the Navy (26 years) we chased submarines and had to learn all about their diesels. What used to amaze me on these big diesels was their low RPMs. They only ran from 500 to 720 RPM. This was why they needed the scavenger blowers because at that low of RPM they couldn't get enough air velocity through the motor.


    I mistakenly said 625 cubic feet for the SSI and I meant cubic inches. Sorry.
     
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  13. eli

    eli Banned

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    Standard Blower Output - Cu. In. per Revolution

    Size Rotor Dia. Rotor Length Standard Helix
    Output High-Helix
    Output
    3-71 5.778" 7.482" 205 -
    4-71 5.778" 9.980" 274 -
    6-71 5.778" 14.975" 411- 472
    8-71 5.778" 15.905" 436 -500
    10-71 5.778" 17.000" 466- 536
    12-71 5.778" 18.000" 494 -568
    14-71 5.778" 19.000" 521- 600

    Notes:From Spuds site
     
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    Last edited: Apr 16, 2009
  14. Money Shot

    Money Shot Member

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  15. DMPE

    DMPE Member

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    Each inch of Rotor length nets 14.4321 cubic inch of displacement per revolution.
    A 14-71 having a 19" rotor length will be calculated as follows.

    14.4321 * 19.00" = 274.2099 cubic inches/Rev/rotor

    274.2099 * 2 = 548.4198 cubic inches / rev total

    The above displacement volume is data from my X3 rotor profile, based on NHRA set 5.840 bore diameter.

    Enjoy your day

    Darren
     
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  16. Dave Koehler

    Dave Koehler Member

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    Roots trivia. Detroit Diesel was the benefactor, not the inventor of the roots. The Roots Brothers made the first ones out of wood in the 1850s to use to move air at a mine or some other industrial application. AND they didn't actually come up with the basic design idea. They just figured out a good use for the idea. Someone else whose name I forget actually did the design the early 1800s. If I remember right the first designs were 2 lobe. This all took place in Indiana where there is more than corn.

    Ain't it cool how the stuff we take somewhat for granted now began before the Civil War? Boy, would those old boys be surprised at the uses.
     
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  17. eli

    eli Banned

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    now for the rest of the story

    From Wikipedia, the free encyclopedia


    It is named for the brothers Philander Higley and Francis Marion Roots of Connersville, Indiana, who first patented the basic design in 1860 as an air pump for use in blast furnaces and other industrial applications. In 1900, Gottlieb Daimler included a Roots-style supercharger in a patented engine design, making the Roots-type supercharger the oldest of the various designs now available.
    see more @ roots superchargers on google
     
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  18. Bottlefed

    Bottlefed New to Blowers

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    As long as were on the subject of roots blower uses lets not forget grain elevators.

    R/G
     
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  19. altered boy

    altered boy Outlaw Altered

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    how would you know??















    ha ha... i keed!! i keed!! thanks for the infor darren... very cool :D:D
     
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  20. 560Jim

    560Jim Member

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    Ha Ha good on ya Mike

    I was wondering how you were going to get that 14,000-71 past tech.
     
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