13mpg-help!!

Discussion in 'Start Your Journey Here' started by endura, Sep 11, 2007.

  1. Arroba

    Arroba Member

    It's not impossible. In fact, it's the only way it can be.

    If a car is locked in a gear, its wheels (mph) are mechanically linked to the engine (rpm). They vary together linearly until the torque converter gets in the game (or your foot with the clutch).

    If someones sees a non-linear dependence between car speed and engine rpm _while in the same gear_ it's because of a torque converter slipping (if the torque converter is locked and this still happens, then you have a _faulty_ torque converter).

    I repeat: once locked in a given gear, your speed will _always_ vary linearly with engine rpm. That's what a gearbox does.
     
  2. endura

    endura Member

    received the scangauge today. will test out different cruising speeds and see what it shows.
     
  3. 2TonJellyBean

    2TonJellyBean Well-Known Member

    endura, good stuff

    Before you get overloaded in all of the rolling numbers, find out what you consume idling (AC off and AC on). That's important for determining how slow you can coast while idling and still be improving your average. For instance, if you burn gas idling at the rate of 2.5 LPH and you're trying to better an average of 14 LHK, then you wouldn't want to coast much at under 20 KPH (2.5 x 100/20 = 12.5 LHK, at 15 KPH, you'll be hurting your average at 16.7 LHK) unless the engine was off.

    You might also want to keep in mind, that slow acceleration can also hurt FE. I'm sure you'll notice that the only time your truck is improving its average is when it's in OD (or coasting in N). I've found that 60% LOD is better than using low loads on my short commutes (and I kept getting more and more lightfooted and expecting better and better results). Try and get into OD quick and then you can accelerate slower after that.

    Keep a little log for you short commutes. That way you can gauge the effect of different strategies on standard drives like dropping off the kids.

    I'm surprised by the coasting. I'm near the lake in miss and I can coast from the QEW to Lakeshore and then from there again down my street.

    It's the little things... if you're cresting a hill, let the speed slide as you go up it and then you can add it back coming down.

    Have fun and good luck...
     
  4. endura

    endura Member

    1-this scangauge device is a fantastic tool.
    2-I'm showing 17mpg at a steady 70mph cruise.

    peak mpg seems to be what I thought. lowest rpm at which TQ locks in top gear. 28mpg at 38mph.

    at a steady cruise, I tried 3rd and 4th gears to get an idea of fuel consumption increase. It's 2mpg lower in third and the revs are about 900rpm higher. which pretty much kills my plans of changing the rear end as I was looking at a 500 rpm drop which probably gives me 1mpg. not very cost effective.

    certainly is an eye opener.
     
  5. 2TonJellyBean

    2TonJellyBean Well-Known Member

    How many GPH or LPH at idle?
     
  6. endura

    endura Member

    .42GPH, I think.
     
  7. endura

    endura Member

    the fuel economy is about 17mpg at 60mph, and it just gets worse after that. now that I can actually see how much fuel it's consuming in real time, I am even more disgusted with this truck.
    I've got the average fuel economy up to a steady 15-16mpg.
    I weighed everything in the bed. it's about 1500lbs. Quite a bit more than I thought.
     
  8. warthog1984

    warthog1984 Well-Known Member

    If I can offer advice. Go to a Ford dealer, take a "test drive" in a F-150 with 4 doors and a 3.31 rear axle. Out of Sight of the Dealership, plug in the SG-II and get those numbers.

    I really think the difference in FE will be substantial enough to warrant regearing the tranny or rear axle (again, at $1500, you'd save that much in a year or two).
     
  9. 2TonJellyBean

    2TonJellyBean Well-Known Member

    Okay so right off the bat you're up between 15 and 23%, amazing what a ScanGauge and improved skill from feedback can do. Excellent start!!!

    I too would try it out on a 3.31 geared Fiso. A more expensive option would be an external OD bolted to the end of the tranny - that would kick serious butt. Leave it off when urban for easier slower 4th entry and lockup, and then out on the open road it would be engaged and slowly roll that V8 over to maximize the efficiency. You'd have to shut off the ext. OD for hills and it would mess up your odometer in your favor whenever used. Tough part is how it would affect your warranty. Okay... so it's a pipe dream while on warranty at least.

    If you doing a lot of 50 KPH speed limit driving, figure out the slowest speed in which you can get the truck into 4th. Whatever increase in geaing you get will increase that speed. Too relaxed a gear and you might not be hitting 4th in the city or risking tickets doing so and this would effectively bring your overall average down.

    Good work though... the 401 is pretty tolerant of people doing the limit or less through the city so you could try that if you can have an extra couple of minutes between transit points.
     
  10. psic

    psic Well-Known Member

    Seems like you're becoming hooked, welcome aboard :D

    As to the 17 mpg at a steady 70 mph: I haven't done 70 mph in months, and I'm sure there are people here who don't really know what 70 mph IS :D
     
  11. endura

    endura Member

    revised figures.

    taken from scangauge. all variables other than engine rpm constant. 10km distance.

    60MPH/4TH GEAR/2000RPM/AVG. 18.4MPG
    60MPH/3RD GEAR/2850RPM/AVG. 14.4MPG

    -a change from my 4.10 to 3.55 gears drops engine by 250RPM at 60MPH.
    -based on above data, reasonable to assume highway gain of approx. 1-1.5 MPG.

    -not cost efficient at 50/50 city/hwy. driving/yr. at approx. 20000 Miles/yr.
     
    Last edited: Oct 2, 2007
  12. endura

    endura Member

    Ordered a 2007 Honda Ridgeline. Loaded the same stuff from an F150 extended cab with an 8 foot box into a truck with a 5 foot box.

    How is that possible you ask?

    The in bed trunk is HUGE. The tailgate opens sideways so access to the bed is fantastic and there is a ton of space under the rear seats for my tools.

    I wouldnt' have believed it myself but the dealership let me take one home to see if everything would fit.

    Thank you Honda.

    Good bye Ford.
     
  13. ILAveo

    ILAveo Well-Known Member

    Keep us posted on how that works. How is it rated for towing? I'm particularly interested because this winter they will be replacing the F150 I've been driving at work and I might have some influence.
     
  14. donfromnaples

    donfromnaples New Member

    Instead of the expense of changing your gears, try a plus two tire size first which would yield you about 3 mpg. For instance, if your stock tires are 265/65/R17 try a 265/75 or a 275/70 tire size. Lower rpms = improved mpg.
     
  15. donfromnaples

    donfromnaples New Member

    Also, are you running full synthetic oil like a 0W-30 blend? This could give you 1 to 2 mpg as well over stock recommended oil viscosity. Another trick I have had good results with is water wetter in your radiator lowering overall engine temp by at about 10 degrees. I live in Southwest Florida so I can run almost pure water with water wetter in the radiator. If you live in hot climate try an 80/20 mix of water/antifreeze with water wetter. Otherwise a 50/50 mix in cooler climates.
     
  16. 98CRV

    98CRV Well-Known Member

    Way cool! Looking for Ridgeline numbers. Post away!
     
  17. Blake

    Blake Well-Known Member

    Colder is not always better ;)

    I'm trying to find more ways to keep the temps higher as we speak.
     
  18. donfromnaples

    donfromnaples New Member

    Do you have a 195 degree thermostat in your truck?
    Next time you need tires, go for the ones with the best rolling resistance.
     
  19. Vooch

    Vooch Well-Known Member

    this thread proves the point that all cars should have iFCDs - well done with the hypermiling !
     
  20. philmcneal

    philmcneal Has it been 10 years? Wow

    please post a review on the ridgeline truck, i heard it sucks for towing. Wouldn't the underpowered 3.5L be bad for towing and result poorer mpg than a 4.5L V8 that can be in its efficent powerband without being overloaded?
     

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