HOW TO: Improve your MPG

Discussion in 'How To' started by VTNomad, Aug 5, 2006.

  1. Okura_hubby

    Okura_hubby Full Access Member

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    If your engine has more power (avalable power), then that means to go 55mph your engine is not working as hard, thus burning less fuel. Because it is more effecient. It is producing more power per stroke/cycle so it requires less cycles to do the same job.

    I saw your thread on altitude. The higher you go, the less air is available, so your engine becomes less efffecient I would think an engine would be more effecient at lower altitudes where air is thicker and the engine can gain more power per stroke. Also you pointed out less air means less air resistance. This is true, I know the Liby is a brick with high suspension so not exactly aerodynamic so not sure how fast you would need to go to notice a difference. And you would probably be burning more gas to get that fast since the altitude has less air for the engine..

    RPM is not constant with HP. Depending on many factors that change dictate how fast RPM's must be to equal same HP. Forgetting wind, terrain and driving habbits.. To go at a said speed requries X amount of HP. Depending on Temperature and Altitude will dictate how much air per cycle the engine can process which will determine how much HP each cycle produces. So the cooler and lower you go the thicker the air the more effecient the engine.

    But the problem is everything is in a constant state of change. Temperature, your location (altitude), your driving habits, duration of your drive. It all affects things.
     
    Last edited: Sep 13, 2011
  2. tjkj2002

    tjkj2002 Full Access Member

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    Modern FI virtually eliminates the efficiency difference between sea level and high altitude,the power difference is there but the efficiency is virtually the same.
     
  3. Okura_hubby

    Okura_hubby Full Access Member

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    I was watching a Top Gear show where they drove these trucks up some mountain somewhere, where the air was so thin they were having head ack's.. And they noted their engines were sucking for HP.

    Your engine is nothing more than a pump. So if there is less air for it to pump, then less HP.. So to get the same results Speed or torque or whatever you will need to apply more gas (decreasing effeciency)..
     
  4. tjkj2002

    tjkj2002 Full Access Member

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    Not with modern FI,yes HP will be reduced but the effeciency will not.Reduced power is the by product of "leaning" out the fuel/air mixture to keep the same effeciency.
     
  5. Okura_hubby

    Okura_hubby Full Access Member

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    After I posted this I read some other threads on other forums. And people were reporting they actually got highter MPG when they went higher elevations..

    And it made sense. The computer was reading the air density (thinner) so it leaned out the fuel mix. Saving fuel. Computers.. Got to love them.. Ha .. But I suspect since less air and less fuel the engine is not producing the same HP per RPM.. Less bang.. If not then why not lean out the engine and bring in less air so its more effecient all the time.. Hmm
     
  6. tjkj2002

    tjkj2002 Full Access Member

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    To much heat,bye-bye pistons and heads.
     
  7. Okura_hubby

    Okura_hubby Full Access Member

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    Your comment about more heat is based on more RPM's? Or is it something else?
     
  8. tjkj2002

    tjkj2002 Full Access Member

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    The leaner the fuel/air mixture the more heat in the combustion chamber.

    A rich fuel/air mixture will naturally runs cooler and a lean fuel/air mixture naturally runs hot.
     
  9. ndz

    ndz Full Access Member

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    I bought a drop in K&N filter. that gave me an extra 3-4mpg. Then i broke off the tab that used to be where im pointing. that gave an additional 4-5mpg.

    IMAG0038.jpg

    edit: i should mention my old paper filter was ready to be changed out
     
    Last edited: Sep 19, 2011
  10. tommudd

    tommudd Moderator Staff Member Moderator

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    So you are saying by installing the K&N and breaking off the air intake you got 7-9 MPG more :happy175::happy175:
    Come on now
     
  11. danh7029

    danh7029 New Member

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    You forgot pumping up the tires to the safest maximum pressure,
    Clean air filter, and good engine tune
     
  12. tjkj2002

    tjkj2002 Full Access Member

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    Never air up your tires to max PSI unless it's the rear tires on a 3/4+ pickup used for towing with E range tires.Less contact area which means less traction and effects handling.
     
  13. baer jeeper

    baer jeeper Full Access Member

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    hmm did exact same thing also changed the spark plugs(cause they were worn out) also went to synthetic oils engine and diffs. according to packaging i should have seen a 12-15 mpg gain.. :smokin: back to stock mpg 20-21mpg no where near the possible 30ish lmfao
     
  14. samlesher

    samlesher Full Access Member

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    For those with a manual transmission, I have read quite a few arguments between those who say you should coast in neutral to save gas (when going downhill, etc) vs. those who say it's actually more efficient to stay in gear at all times.

    Does anyone have two cents to offer on that, specifically in regards to the NV-3550?
     
  15. tjkj2002

    tjkj2002 Full Access Member

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    If going downhill stay in gear,not only for safety but it will actually shutoff the fuel going into the engine if your not stepping on the gas pedal.If in "N" your still using gas since the engine is idling.
     
  16. sevenhelmet

    sevenhelmet Full Access Member

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    Hey, I didn't know that! Cool.
     
  17. pure_mahem

    pure_mahem New Member

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    Could always switch to Diesel or propane, lol!
     
  18. Liberty65

    Liberty65 New Member

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    2005 with a six speed tranny....Wow I had know idea they made them with that. What kind of mileage are you getting on the highway @65mph? Do you have an intake or exhaust upgrade? Thanks.
     
    Last edited: Feb 3, 2013
  19. baer jeeper

    baer jeeper Full Access Member

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    #1 should be maintenance :p
     
  20. Lightningdan

    Lightningdan New Member

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    If you live in an area that sells ethanol fuel, stop using it and use straight unleaded, you should see a gain of 2mpg more without the corn in your fuel. I know here in South Dakota, if I run the ethanol fuel my mileage suffers for it.