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Hand Calc vs computer mpg...

Discussion in 'General Tundra Discussion' started by RonW, Jul 7, 2018.

  1. Jul 7, 2018 at 3:22 PM
    #1
    RonW

    RonW [OP] New Member

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    I don't know why nobody trusts technology now days.

    I hand calculated the last two times and it was within .1 of what the computer said.

    Bunch of old folks...:rofl:
     
    Last edited: Jul 7, 2018
  2. Jul 7, 2018 at 3:54 PM
    #2
    Yzed608

    Yzed608 New Member

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    Is this the average MPG you're looking at (I don't know if the 18's have a "since last fillup" option)? I keep track at every fill up, one of the things I record is distance to empty right after I fill it. I've been meaning to calculate how close it is to the MPG from the tank following to see how accurate it is, just been too lazy :anonymous:. My calculated average doesn't match my stated average by about .5-.6MPG, but I missed a couple fill-ups at the start of owning the truck.
     
  3. Jul 7, 2018 at 4:17 PM
    #3
    Black Wolf

    Black Wolf Addicted to petrified wood apparently

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    Yeah...my 07 indicator is average mpg computer calculated from a reset baseline. Maybe new Tundras have that "since last fill up" capability. I've averaged over 15 mpg on trips to my property and my baseline average mph might go from 10.8 to 11.2 temporarily. Has nothing to do with trusting technology. Two totally different methods based on different timelines. Coming out the same in my case would be a fluke.
     
    Last edited: Jul 7, 2018
  4. Jul 7, 2018 at 4:22 PM
    #4
    yoneytan

    yoneytan New Member

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    My truck shows 10.3 but manually calculating its more like 11.5. Either way I think the MPG’s suck. Doesn’t change much for me as I don’t drive so much but still envy of the folks getting 15/16 and higher.
     
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  5. Jul 7, 2018 at 4:27 PM
    #5
    15whtrd

    15whtrd Mr. Blonde

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    My 15 is an overall mpg average unless you reset it after each fill up.
     
  6. Jul 7, 2018 at 4:27 PM
    #6
    Black Wolf

    Black Wolf Addicted to petrified wood apparently

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    My reset baseline goes back four years. No way will it ever remotely be close in updating display to 15+ mpg on freeway drive on a 200 mile trip. If I reset my Tundra, as in disconnecting battery awhile before I left...a new time line would be established and in theory display the mpg pretty darn close to what I can hand calculate.
     
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  7. Jul 7, 2018 at 4:33 PM
    #7
    Black Wolf

    Black Wolf Addicted to petrified wood apparently

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    Mine stays pretty much at 10.8 and rarely goes up because I only make a few long distant trips each year. Most of my driving is city so it's going to always be close to the 10.8 average unless I go to lighter tires, or someone steals my tailgate......(which is McGaurd protected) haha..
     
  8. Jul 7, 2018 at 4:36 PM
    #8
    Black Wolf

    Black Wolf Addicted to petrified wood apparently

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    I trust technology that works. This old fart works with some of the latest and greatest measuring test equipment on the planet, on a daily basis.......:rofl:
     
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  9. Jul 7, 2018 at 4:38 PM
    #9
    Coolhardy

    Coolhardy New Member

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    Is your tundra stock?
    My computer shows 17mpg
    While fuelly tells me 11.5
     
  10. Jul 7, 2018 at 4:41 PM
    #10
    RonW

    RonW [OP] New Member

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    Yeah, the 18s have a "tank average" that resets when you fill up. That's what I'm looking at. That can't be manually reset as far as I know.

    For what it's worth I don't care about mpg much. And if I did it's too late now since I own the truck. I was just curious as to how much off it is.

    I will say it's closer now than when I first got it. It was off by .5 or so then.
     
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  11. Jul 7, 2018 at 4:43 PM
    #11
    RonW

    RonW [OP] New Member

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    Yes, stock except some sweet ass seat covers.
     
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  12. Jul 7, 2018 at 4:47 PM
    #12
    RonW

    RonW [OP] New Member

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    I mean it knows how much fuel is in the tank vs how much was in the tank. And how many miles it went. So it really calculates the same way you do.

    How many miles vs how many gallons used.
     
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  13. Jul 7, 2018 at 4:47 PM
    #13
    yoneytan

    yoneytan New Member

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    My truck is lifted 3/1 with 295/70’s on 18x9 Methods. Seriously considering 488 gears.
     
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  14. Jul 7, 2018 at 4:49 PM
    #14
    RonW

    RonW [OP] New Member

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    But even then it will know how far it went vs how many gallons used.

    Unless the miles driven is that far off due to bigger tires. In which case hand Calc isn't going to be good either.

    Right?
     
  15. Jul 7, 2018 at 4:58 PM
    #15
    yoneytan

    yoneytan New Member

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    I guess you’re right. When my speedo is at 70mph im actually driving 74-75mph. So for instance I drove 221 miles (according to my odometer) since my last fill up which was 20 gallons. That’s equates to 11mpg but in reality I drove more than 220 miles. Not sure how to get the exact miles driven but I’m figuring I did around 235 which would equal to 11.75mpg. I’m sure I’m off just don’t know by how much.
     
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  16. Jul 7, 2018 at 5:10 PM
    #16
    Black Wolf

    Black Wolf Addicted to petrified wood apparently

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    I wish my 07 had that. The only way for me to reset is the battery disconnect pain in the a**. I'm thinking your computer calc should be pretty good based on a new fill up average.
     
  17. Jul 7, 2018 at 5:13 PM
    #17
    Black Wolf

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    Our fuel monitoring system would be as good as it gets if based on fuel weight but that could be a bit pricey I guess.
     
  18. Jul 7, 2018 at 5:17 PM
    #18
    Black Wolf

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    Maybe you should do the battery disconnect and start a new baseline. So your displayed is 17 and recent "fuelly" hand calc 11.5?
     
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  19. Jul 7, 2018 at 5:45 PM
    #19
    Coolhardy

    Coolhardy New Member

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    Good idea. I m putting in dual bettery next week. Will try and see. Yes, displayed 17-18 fuelly so far best is 11.9
     
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  20. Jul 7, 2018 at 5:47 PM
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    BuckWallace

    BuckWallace Ball don't lie.

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    I also compare my own calculation to the truck's computer and am usually within 1 or 2 tenths.
     
  21. Jul 7, 2018 at 5:48 PM
    #21
    Coolhardy

    Coolhardy New Member

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    I just did 488.
     
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  22. Jul 7, 2018 at 5:57 PM
    #22
    Black Wolf

    Black Wolf Addicted to petrified wood apparently

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    Want to see that dual setup when you are done!
     
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  23. Jul 7, 2018 at 6:13 PM
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    yoneytan

    yoneytan New Member

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    How is it different on take off, highway and all around?
     
  24. Jul 7, 2018 at 6:36 PM
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    Yzed608

    Yzed608 New Member

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    https://www.tacomaworld.com/tirecalc

    Put your old tire size in and your new, it will tell you the speed difference. Take the ratio to find your actual distance driven and use that for the MPG calculations.
     
  25. Jul 7, 2018 at 7:04 PM
    #25
    Coolhardy

    Coolhardy New Member

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    Ya, in a week or so i will post. Got all the parts this week, Doing a bunch of mods next week. After that, i m done for this year at least.
     
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  26. Jul 7, 2018 at 7:10 PM
    #26
    Coolhardy

    Coolhardy New Member

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    Hard to tell cause I did gears and Supercharger at the sametime. I also did Auburn LSD. Truck flies now.
     
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  27. Jul 7, 2018 at 7:15 PM
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    RonW

    RonW [OP] New Member

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    I feel like I need a supercharger. I don't know why but I just feel like it.
     
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  28. Jul 7, 2018 at 7:16 PM
    #28
    Coolhardy

    Coolhardy New Member

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    You will love it. Best mod so far.....
     
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  29. Jul 7, 2018 at 7:40 PM
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    Black Wolf

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    You know why.....:burnrubber:
     

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