Fuel requirement calculation?

Discussion in 'PSI Superchargers Tech Questions' started by WJ Birmingham, Jan 2, 2008.

  1. WJ Birmingham

    WJ Birmingham New Member

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    Ok, here goes.

    Trying to figure out the maximum size fuel pump I need. See if these numbers jive with you guys.

    To sustain 1 HP you need 0.7073 BTU per second

    Therefore 2100 HP = 1485.33 BTU per second

    Methanol has 8600 BTU per pound and weighs 6.63 lb/gal...

    So based on that, 1 gallon will sustain 2100 HP for 5.79 seconds?

    60 seconds divided by 5.79 = 10.36 GPM

    Is that right? Sure doesn't seem right.

    HELP!?
     
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    Last edited: Jan 2, 2008
  2. crashly

    crashly Member

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    WJ...
    here is a few post from a fuel math question i asked a while ago...

    http://www.insidetopalcohol.com/showthread.php?t=9091&highlight=travis

    it was regarding a turbo meth engine, but mike canter put some great ideas across...

    also, a rough formula i have heard is 5 gal per 1000 hp
    therefore your 2100 hp requires approx 10.5
    i have not flowed this formula .... so take it as a guess...

    cheers
    ash
     
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  3. WIZBANG

    WIZBANG Member

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    Hmmm, I have the following:
    Blown Alcohol 440 cu in Chevy
    8-71 makes 25 lbs
    I put 11.2 gpm in it ???????
     
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  4. WJ Birmingham

    WJ Birmingham New Member

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    Crashly;

    Thanks much.

    So, according to Mike's figure of ".00529"... 2100 * .00529 = 11.1 GPM...

    Now, knowing that pressure is nothing more than excess volume...

    How much excess volume do I want? 13GPM, 15GPM, 18GPM?
     
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  5. crashly

    crashly Member

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    i would at a guess go with 11.1 to be safe

    you can always take fuel out...
    depends on how good your blower is, camshaft, ignition etc etc...
    1.85 to 2 bsfc would be a est figure.

    the other figures i gave as a guide only !!
    5 gals per 1000 hp .......many blower guys qoute this figure over here.

    i mainly work with turbo mech injected meth engines...
    we run between at about the 1.2 bsfc figures ( no blower to sustain..)

    cheers
    ash
     
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  6. crashly

    crashly Member

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    WJ

    the 13 gal pump probaly is a end 110. they not flow 13 gals, more like 12.2 to 12.4 gals

    the 15 gal pump is a end 990 ? and 18 gal is end 1100 ??
    size pump depends on how big / many bypasses you have to get rid of fuel at idle.... and fuel requirements ( gal / min )in the rpm range...

    go a bit bigger for pump wear and safety..
    cheers
    ash
     
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  7. fasttimesracing

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    i have a 540 with a ssi f rotor and a msd 20 mag. with dart heads that flow around 400. the blower is spinnig 35 over at this point. i run a 990 pump with a pump sizer in it to get the mani jet size down in the high 90s. no hs yet. runs good
     
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  8. SoDak

    SoDak Active Member

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    Evidently tractorpulling is enough of a different load. We run about 1.3 BSFC, these are BBC's, Dart 360's, SSI HH F-2 8-71's, SM IV.
    I can't imagine the big chamber with a big dome sticking into it is efficient. After all, thats what BSFC is saying,,, how much of your fuel energy turns into flywheel energy.

    Any ideas why mine is so low?

    One thing might be this; on average, we hit about 8000 RPM within the first 3 seconds,(this is controlled by the driver) then the load will pull the motors down to about 7000 over the next 8-9 seconds.
    Most of you guys are excellerating the engines.
     
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  9. KDavidson

    KDavidson Member

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    Crashly,

    Go to Spud Miller's web site, Fuel Injectionn Enterprises. Use his calculator, BUT use it wisely. I run the car, read the plugs and put in the pertinent info and then make changes off his calculator. It's a nice way to keep things in the safe zone. BUT you need to know your pump flow #'s and other items.

    Keith
     
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  10. WJ Birmingham

    WJ Birmingham New Member

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    Called Gorr and Enderle...

    Jim @ Enderle said a 990...

    Ralph said to use the baseline of .3 GPM per PSI. 990 or 1100 with pump saver.
     
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  11. AnimalCrew

    AnimalCrew New Member

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    I don't remember what the difference in cost is, but it's easy to put in a loop (pump sizer) and the 1100 covers you if you decide to put more blower on it like we are doing now. Or if you want to bypass more fuel with multiple lean outs.

    Buy one pump and cover yourself for the foreseeable future.

    Troy.
     
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  12. WJ Birmingham

    WJ Birmingham New Member

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    I concur. Just purchased a Hilborn -4 (17.1 GPM) from Santo (BLOWN INCOME on this forum)...

    I'll use it with a pump saver and have a cushion.
     
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  13. Eric David Bru

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    You mean a pump sizer. :)

    EDB
     
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