required gpm

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by WIDEOPEN231, Jun 19, 2017.

  1. WIDEOPEN231

    WIDEOPEN231 Member

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    Working with fella on his TA/D. He has new enderle dual gear pump 19.5 gpm. Its on 509 ci AJPE Olds, 14-71 littlefield 54%. I figure it needs 13 gpm to motor. Figured checking with few of you guys on what you think.

    Asking because as he has it now my calculations he is at 12.2 to motor.

    While at it what pressure are you running at? Computer show his at 93. I like to be around 15e0 or above.
     
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  2. Mike Canter

    Mike Canter Top Dragster

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    How much boost at 8000 rpm. When you say 13 GPM needed then what DA is that at and what rpm?

    The standard pressure out of the pump before the BV is 125-130 psi at 8000 rpm
     
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  3. WIDEOPEN231

    WIDEOPEN231 Member

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    43 @ 8200 Da was right at 1200'.

    Normally on my stuff little higher than 130p psi around 150,mainly because Ralph set it up that way and most his flow charts work off 150 psi and operating close to it kept me from having to run new flows for lower pressure when I wanted to calculate actual flow to motor.
     
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  4. Mike Canter

    Mike Canter Top Dragster

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    13 GPM with 43 lbs of boost at 1200 ft is lean. i would start out with 14.4 GPM and get a plug reading and go from there. A lot depends on the camshaft.
     
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  5. WIDEOPEN231

    WIDEOPEN231 Member

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    not crazy about autolite plugs they run. Even now they do not show any heat.
    Computer readings cpl cylinders in 920 range. 12.2 to 12.5 gpm to motor,1/8 mile only reason got by with it. Most of the time I would call 920 fat(not 1/8 mile. This motor has hurt pistons with temps at 1000*.My thoughts bad placement of sensor or computer readings to slow to catch spikes from pump issue(old pump enderle 1200). It is what it is for now.

    As for cam ,no idea.Motor was bought injector to pan,used. Normally I would build my own combo,but as said this is someone else's deal.
     
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  6. Mike Canter

    Mike Canter Top Dragster

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    You cannot read Autolight plugs for combustion chamber temps. You need to switch to an NGK plug probably a R5671A-10 or a 6061-10. It takes fuel to make power so running a motor lean is not good and does damage if something small goes wrong. I would highly recommend not tuning by EGTs and tune by reading the plugs.
     
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    Last edited: Jun 20, 2017
  7. WIDEOPEN231

    WIDEOPEN231 Member

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    Agree on NGK's.Again not my car. Never had problem using EGT's,but then I always verify temps and plugs agree and bearings just for another opion.
     
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  8. bob szabo

    bob szabo FC / altered

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    While it may be late in the response, I ran some numbers through our ProCalc on this combination; examining the air to fuel ratio (afr) as a tuning tool that we used for years; we detemined nozzles & main bypass combinations for 93 psi, approx 1200 ft DA, moderate blower wear, at various GPMs to the motor per the thread; and did a data analysis using Excel program tools; note the following:

    upload_2017-7-28_21-30-52.png

    Air to fuel ratios in the low 3's are about as rich as we have seen in high blower OD combos. Less than that may drop holes and/or drop power.

    Air to fuel ratios close to 4 to 1 are about as lean as we have seen in blown BBCs, usually with less blower. Air to fuel ratios in the mid to high 4s will bang a blower.

    We had a lot of success tying air to fuel ratio to plug readings in our blown car through the years. Once a good air to fuel ratio was found, we could reproduce our spark plug readings at any DA or blower overdrive by jetting to maintain that air to fuel ratio.

    A pdf of the Excel file we generated from our ProCalc jetting calculator for the analysis is attached. We assumed 16 nozzles with an average diameter that was needed for the fuel pressure and fuel to the motor goal.

    Note: That was done without knowing the specific nozzle distribution or the number of nozzles. However to meet those goals, the nozzle area would be specified regardless of nozzle distribution.

    That and a lot of other data are shown in the jetting, blower OD, and DA record that is attached. Email or call if you have any more questions.

    Bob Szabo
    bob@racecarbook.com
    http://racecarbook.com
    http://airdensityonline.com
    (916) 419 6649
     

    Attached Files:

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