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Thread: $EE Instantanious Fuel Consumption

  1. #1
    Fuel Injected! Terminal_Crazy's Avatar
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    $EE Instantanious Fuel Consumption

    Evening all,
    Following this thread: http://www.gearhead-efi.com/Fuel-Inj...-thing!/page56

    I don't think Steveo got to put it into EEHack.

    As an interest, I've written a filter for my software to average the fuel usage & calculate the transmission gear for each mph on a log.
    Data is calculated as min, max & average fuel consumption.
    There is no minimum count filter for the averages yet so any cell can get a count.

    This was a short log from today which I found surprising.
    I've never been able to convince myself whether lugging it in 6th or a light load in 4th is best or makes much difference.




    Thanks
    Mitch
    Attached Files Attached Files
    Last edited by Terminal_Crazy; 02-22-2019 at 11:15 PM. Reason: add report
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  2. #2
    LT1 specialist steveo's Avatar
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    nice job!

    i was planning to do it but never got around to it, believe it or not i suck really badly at math.

    when i tune these days i forget actual economy calculation (which is painful to look at with a V8 anyway) i would go by MAP and injector bpw for maximum fuel economy during cruise. if ya aim for more vacuum and less injector pulse it's as good as it gets

  3. #3
    Fuel Injected! Terminal_Crazy's Avatar
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    I’ve kept a log of all fuel used since i bought this car. First drive home was about 200 miles on motorway but i didn’t know how much fuel it had. My logs guesstimate 29mpg which i thought was a little high, 25 being more likely.
    Average for the car rapidly dropped to 17 but only used for short trips and tooling about.
    Since the rebuild that’s edged into 16 although most of that is in the garage which has reduced my figures.
    Fuel consumption hasn’t really been a consideration. To see a tuned motor get over 30mpg is pretty cool.
    It’s quite happy in 6th at 25mph.

    Mitch
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  4. #4
    Fuel Injected! Terminal_Crazy's Avatar
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    Steveo
    What setup is required to buid EEHack and Trimalyzer?

    Tia
    Mitch
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  5. #5
    LT1 specialist steveo's Avatar
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    just qt 5.x. you can install it with the mingw compiler and it's free. the ui is all done with qt creator so you can visually edit ui controls

    https://www.qt.io/download

    source code is all on github (although the latest trimalyzer isn't yet).

    https://github.com/resfilter/

  6. #6
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    I’ve kept a log of all fuel used since i bought this car.
    In a land of Opel/Vauxhall 2.2 litre "big block" engines, I'm guessing the 5.7 is an undesirable engine? If so, I wouldn't mention the potential fuel economy in public. I'd want an inexpensive market for spares.

  7. #7
    Fuel Injected! Terminal_Crazy's Avatar
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    There are still a lot of US vehicles over here.
    Back in the 70’s and 80’s there were loads of Muscle cars and big cruisers.
    We had lots of US airbases around the country at the time.
    Cars were cheap hi performance.
    Once the air bases started closing late 80’s the jap imports started appearing and trends changed a bit.
    Both my cars came from RAF Mildenhall about 200 miles away.
    My old 305 camaro did 20mpg. Headers manifold and holley it would do 30.
    I got it down to 12.
    Had a 74 2.8 twin cam mercedes that only did 20
    A 1100 mini that only did 20
    So if i can get over 20 on a run i’m happy.
    Nice to know I can get 30+ if i baby it on a decent run.

    Mitch
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  8. #8
    Fuel Injected!
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    I had some formulas for tunerpro long time ago but were too awkward so I made this one. They seem to work fine. Tested in tunerpro.
    It is for instantaneous fuel flow, I never figured the average but there you need total distance travelled which is not so easy to calculate in tunerpro.
    When the speed is zero they output wierd results. The perfect one will be able to switch to L/hr or G/hr when the car is not moving.


    (((((A*60/(B*1.61))*((C*2)+(D*2)))/1000)*(E*0.12599788))*0.001335292)*100 = l/100km

    2.3521/((((((A*60/(B*1.61))*((C*2)+(D*2)))/1000)*(E*0.12599788))*0.001335292)) =US gpm

    2.82481/((((((A*60/(B*1.61))*((C*2)+(D*2)))/1000)*(E*0.12599788))*0.001335292)) = UK gpm

    A=RPM
    B=MPH
    C=LBPW
    D=RBPW
    E=Inj fuel flow in G/hr


    Here is explanation of the formula

    RPM*60/(MPH*1.61) this part calculates how many revolutions the engine makes for 1 km with vehicle speed of 1km/hr

    (lbpw*2)+(rbpw*2) total BPW in ms for one engine revolution. Since we have 4 injectors opened for 1 crank revolution 2 from left and 2 from right.

    When we multiply the RPM*60/(MPH*1.61)*(lbpw*2)+(rbpw*2) we get the total [bpw]open time of injectors for 1 kilometer in miliseconds.

    We need to convert to seconds so the whole thing is divided by 1000


    (g/hr[fuel flow]*0.12599788) here we convert fuel flow from gallons/hr to grams/second

    (A*60/(B*1.61))*((C*2)+(D*2)))/1000)*(E*0.12599788)) this part gives us grams of fuel for 1 kilometer

    than we multiply it with
    *0.001335292 to convert fuel from weight to volume or grams to liters.

    At the end we have liters per 1 kilometer so a multplication by 100 gives us l/100km.

    The other two formulas convert the result to US gallons per mile and UK gallons per mile
    Attached Files Attached Files
    Last edited by kur4o; 02-24-2019 at 12:18 AM.

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