Whipple A980 Nozzle Area Calcs.

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Scooby1, Mar 16, 2019.

  1. Scooby1

    Scooby1 New Member

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    Hey guys, firstly thank you to everyone on here for the great source of information.
    It has helped me to run our very low budget aussie k boat racing team with very few issues and i am very greatful for your help.
    With our 16/71 hh i have been using the .36 x boost number method of determining nozzle area and have found this a very safe calculation to use. I have actually found .33 closer for what we need but i think that is due to the lower compression (9 to 1)on our endurance type application.
    We are now in the process of switching to a Whipple and aiming for 25 to 28 pounds of boost.
    My question is would i be safe to assume this .36 x boost calc is still the one to use, or is it too lean?
    Thanks in advance and once again for all the great advice that you guys post.
    Cheers Jamie.
     
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  2. Mike Canter

    Mike Canter Top Dragster
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    Yes, the calculation will be the same.
     
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  3. Scooby1

    Scooby1 New Member

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    Thanks Mike will continue to use the formula.
    Cheers Jamie
     
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  4. Mike Canter

    Mike Canter Top Dragster
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    I have used it with roots, screw and whipped blowers. The engine doesn’t know what is sitting on top
     
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  5. Scooby1

    Scooby1 New Member

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    Its been handy for me too over a variety of combinations.
    Also would i be correct in assuming a whipple at a relatively lower overdrive (around 30 to 35%) that we will run is going to be more efficient than a rootes pretty much everywhere and apart from the appropriate loop (on a 990) i was not looking to be running a high speed in the system?
    Thanks for the replies.
     
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  6. Dale H.

    Dale H. Member

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    The port nozzle stagger is likely different
     
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  7. WIDEOPEN231

    WIDEOPEN231 Member

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    when I went from hi helix to whipple I basically flipped the fuel system. 2 went to 7 say flipped front to rear and side to side. It worked as good starting point. Whipple is way more efficient piece. Off base tuneup and I was 5.60 to 5.70's out the gate and this was in 1996 so way back when.LOL
     
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  8. Scooby1

    Scooby1 New Member

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    We are going from a 16 HH to the screw i was about 8 nozzle sizes smaller at the back. I guess the front of the whipple gets a lot more fuel than the back?
     
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  9. nitrowannabe

    nitrowannabe Member

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    Re read his post. Your small # 7 becomes front # 2. The screw discharges to the rear doesn't it ?
     
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  10. Scooby1

    Scooby1 New Member

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    Yes it does but after 25 years of doing the opposite i have to be told twice lol :)
    Cheers guys
     
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  11. MKR-588

    MKR-588 Member

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    Can you please explain the .36 x boost rule for working out nozzle area?
     
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  12. Scooby1

    Scooby1 New Member

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    The formula of .36 x boost figure is a gpm starting point for the motor.
    Example .36 x 50 pounds = 18 gpm required to motor
     
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  13. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    That's not nozzle area, that's gpm.

    Nozzle area is a function of pump size and boost to create a desired fuel pressure and curve.
     
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