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Driving for economy

Discussion in 'Racing and Driving Techniques' started by K2e2vin, Apr 26, 2006.

  1. K2e2vin

    K2e2vin Senior Member

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    I've been shifting at 2000-2500rpms to keep noise down(but like 25%-50% throttle). Is shifting this low hurting or helping fuel economy?
     
  2. eg6sir

    eg6sir Supa Mod Moderator VIP

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    good question.. i have been wondering the same thing.. my gas seems to disappear rather quickly and i drive the speed limit..
     
  3. wanderinman

    wanderinman Senior Member

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    I was also wondering the same thing. Moreso whether riding 4th or 5th around town is better. I use less throttle in 4th, but spin more RPMs.

    Does anybody know of a fuel flow gauge that can be hooked up, it would be the easiest way to tell if you are actually using more/less fuel.

    EDIT- K2e2vin, just noticed your from Raleigh as well, are you from here?
     
  4. Citizen_Insane

    Citizen_Insane Senior Member

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    Well...thing about it from a completely scientific standpoint. The injector is told how long to fire based on 2 things: RPM and Load. For anyone that's tuned, you'll know this because its how fuel maps are set up.

    So, to get optimum gas mileage, you'll want to use as little throttle as possible and keep your RPM's to a min.

    Since I drive rarely, I'm on the throttle hard all the time up into the high RPM's and don't give a shit I only get 25mpg. (lol, I complain about getting 25 from a modified car).
     
  5. VTECin5th

    VTECin5th Administrator

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    It's kinda weird but when i was driving at 85mph (almost 5k rpm) i got 45-50mpg, and at 70 (4.5k rpm) i got 35-40mpg.
     
  6. K2e2vin

    K2e2vin Senior Member

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    I'm wondering the same thing; my cousins BMW has that "economy" gauge(e36 and e46 generation 325i), and my mom's Chrysler has a digital one.

    Yea, I'm from Raleigh, born and raised. I live in the southeastern area of Raleigh.
     
  7. wanderinman

    wanderinman Senior Member

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    Well, think about it this way. Instead of putting fuel into a motor think of it as painting a line on the road. If your spraying a very small line going 80 mph that line is going to be long as all getout. A very slightly small line going 10mph slower is not going to be as long (miles per gallon of paint).

    Usually though gas mileage does go way down as you get faster due to drag and whatnot, so that is an interesting result.




    As to K2e2vin, I moved here about 15 years ago, used to live in NE raleigh now I am out in Cary near the fairgrounds. Where did you go to high school?
     
  8. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Your engine might be operating in a more efficient state at the higher engine speed, and at a time when the drag force difference between the two speeds isn't that great. As you reach your torque peak, your engine is making more torque with less fuel (per lb/ft), so it's actually possible to be more efficient at higher speeds. It's weird but true.
     
  9. VTECin5th

    VTECin5th Administrator

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    This is exactly what i thought Cal, it even sounds better the closer i get to 4900-5100 rpms, the engine gets more of a 'solid' breathing sound and the gas mileage is like wh0a.
    I usually get around 30-35 in the city 35+ on the freeway.. slightly higher on acetone.
    The 48s-50mpgs were with a full car+passenger and no Acetone, i can't complain for b16 gearing.
    My buddy's coupe went from 210mpTank to 330mpTank on 2 ounces of Acetone in 10 gallons of gas .. :)
     
  10. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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  11. VTECin5th

    VTECin5th Administrator

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    Read @
    http://SmartGas.net

    I didn't believe it either so we tried it.
    the coupe is a miracle story, we all noticed better gas mileage but 210 to 330 is not what we expected either.
    4/4 cars now are running better :)

    I <3 Chevron :ph34r:
     
  12. EGProject

    EGProject YEEEEAAHHHHH

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    Clayton needs to build me one of those DPFI D15B2 wonders.

    60mpg :ph34r:
     
  13. K2e2vin

    K2e2vin Senior Member

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    I went to Enloe HS. I used to work at the CookOut that's around that fairground(Western Blvd, near NCSU campus).


    Alright, so it's best to cruise at around where torque starts peaking out? What about shift points for city driving? And what's the best way to deal with consecutive hills?
     
  14. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Time to read... 210 to 330 really does sound WAY too good to be true.


    Huh? What's this? More info!
     
  15. VTECin5th

    VTECin5th Administrator

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    I read Acetone will clean the combustion chambers, we just guessed they were really dirty or somethin.
    My car went from about 120 to 150 for 4 gallons in city driving.
    60mpg sounds better though... [​IMG]
     
  16. TurboMirage

    TurboMirage YEEAAAHHH VIP

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    the acetone experiment in the mirage was a success, but given the fact the motor is ready to shit, i got a ~40 mile increase.
     
  17. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    I'll be trying it out in the truck.
     
  18. Celerity

    Celerity Well-Known Member

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    Less throttle = less fuel used.

    I take my cars to 3500 or 4000 every shift, but it takes me time to get there. I don' tgive it a lot of gas.
     
  19. flydex28

    flydex28 Senior Member

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    Well that was certainly interesting...has anybody used this "ScanGauge" that he was talking about ...or anything like it? I think I might want to try this.
     
  20. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    It's just an OBD2 scan tool. The Nissan guys like to use one plugged into their "consult" ports. Get a Honda OBD2 scan tool and you'll be able to do the same thing.
     
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