2017 Civic Sedan 1.5t 6mt steady states

Discussion in 'Honda' started by Carcus, Dec 12, 2016.

  1. Carcus

    Carcus Well-Known Member

    Suburban driving update: ...

    Old technique: Slower acceleration, skip shift, get to 6th gear - targeting 45 mph, shift to neutral and coast when I can. = 40 to 45 mpg

    New technique: Quicker acceleration, skip shift, get to 5th gear and hold just under 40 mph with some pulse and glide, "engine brake" staying in gear in 5th for some of the deceleration . = 45 to 55 mpg.

    iow, suburban driving with old technique would yield low 40's, new technique looks like 50+ is possible. There was a lot of time when I should have been in 5th instead of 6th, and coasting down in gear likely has a fair amount lower fuel flow than coasting down in neutral. (I have not hooked the scan gauge up to verify)

    /no engine off in any of this
     
    Last edited: Aug 11, 2017
  2. BillLin

    BillLin MASS: 2018 Bolt EV and 2017 Prime

    ...but effectively off when coasting in gear, right? Very hybrid like! :)

    Edit: Great job adapting!
     
    Last edited: Aug 11, 2017
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  3. Carcus

    Carcus Well-Known Member

    It would seem so, .. Here's a Honda discussion (Fit, not civic) ..... which makes me wonder just what all the 1.5t parameters might be where an "in-gear coast" would use less fuel (0 fuel(?)) than an out of gear coast".
    https://www.fitfreak.net/forums/general-fit-talk/62367-fuel-cutoff-control-2.html

    Well, .... thanks. It took me longer than it should have to discover that, but hey ,... better late than never.
     
    Last edited: Aug 11, 2017
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  4. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    On my (Fit, not Civic), the fuel cut parameters are simple: engine braking above 1200 rpm. It also adds a lot of drag which is why I do all my coasting in neutral unless downhill or needing to stop anyway, like a red light.
     
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  5. Carcus

    Carcus Well-Known Member

    Are your neutral coasts ice on or ice off?
     
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  6. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    Off. Which adds its own challenges. My 5 mile commute often doesn't get it up to full operating temperature (177F this morning). That means the whole trip is spent in the fuel-thirsty warmup mode.
     
  7. Carcus

    Carcus Well-Known Member

    Another 91 octane E0 verification, steady state mpgs increase by about 5% to 7% vs 87 E0. 87 E10 is roughly 5% to 7% worse than 87 E0.

    I'm still averaging 45 mpg on mostly 87 E0.

    Guessing:
    If I was using 87 E10 then it would probably be about 42 mpg.
    If I was using 91 E0 then it would probably be about 46-47 mpg.

    I may try to run several tanks of the high grade $tuff to confirm.
     
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  8. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Carcus:

    That is an incredible increase!!!

    Wayne
     
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  9. Carcus

    Carcus Well-Known Member

    Yeah, I'm not sure I believe it myself, ... but although this last check was a quick one, .. it came out just like before.

    So I'll run at least a few tanks of 91 E0 this spring/summer and see ....
     
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  10. Carcus

    Carcus Well-Known Member

    The numbers are in :
    (data from : 20 mos. and 20,000 miles, 47 fill ups)

    87 E10: 43.4 mpg
    87 E0: 45.5 mpg
    91 E0: 46.8 mpg

    4.7% increase in mpg -- 87 E10 to 87 E0
    2.9%
    increase in mpg -- 87 E0 to 91 E0

    My E10 fills were what I consider high quality fuel (I.e. shell) ... so I suspect cheap 87 E0 would be another 2 or 3% less mpg (not verified, .. but I really don't want to run the cheap stuff (Racetrack, Quicktrip) through my car)

    /put another way -- a near 8% mpg increase due to fuel has been verified, and I suspect a full on "worst fuel to best fuel" comparison would show a 10% to 12% increase in mpg.
     
    Last edited: Aug 1, 2018
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  11. Jay

    Jay Well-Known Member

    I see similar increases in FE from E10 to E0 with my Acura RSX. I'm embarassed to tell people how much better E0 is in my car because the math doesn't work out that it should be that much better, but there it is. My suspicion is that E10 is not really E10 but much higher ethanol content.
     
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  12. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    I smell an ethanol conspiracy. But I see conspiracy everywhere.
    It's not paranoia if you KNOW they're out to get ya.
    Anyway , I'd have to go way the heck out of my way
    to find E0 here in the Land of Madigan.
     
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  13. Carcus

    Carcus Well-Known Member

    ... complicated by the fact that denaturant is added (in varying amounts) to the ethanol, and also effects mpg...
    .... further complicated by the fact that there's different types/amounts of "special additives" , and also effects mpg
    ... further complicated by the fact that there are summer and winter blends, and also effects mpg

    ,.. so yah, you can see trends by keeping track with a mileage log, but getting a firm handle on what's going on out there is complicated

    /having said all that, I still think the EIA's "3% mpg loss ( E10 vs E0)" lies somewhere between highly questionable and flat out wrong.
    https://www.eia.gov/tools/faqs/faq.php?id=27&t=4
     
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  14. Carcus

    Carcus Well-Known Member

    Got a chance to drive an '18 sedan 1.5t with the CVT. So compared to the 6mt: -----

    I would say good city mpg with the CVT is a little easier to attain for the average driver.
    Highway mpg takes a hit, ... a roughly 6%+ drop on the quick steady state test I did.
    /Honda rates both vehicles at 42 mpg hwy, ... imo, ..the real number on the 6mt sedan should be 45 mpg. -- Honda probably held it back for marketing purposes.

    Highway rpms do stay noticeably lower -- 200 to 500 rpm .. which results in a little less noise in the cabin while cruising down the highway.
    //the cvt seems to be a fine transmission, well behaved, good mannerisms ,. . no real complaints.
     
    Last edited: Aug 6, 2018
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  15. RedylC94

    RedylC94 Well-Known Member

    If the engine spins more slowly, yet burns more fuel under the same conditions, that would seem to imply a lot of power is wasted in the transmission. Is there another explanation?
     
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  16. Carcus

    Carcus Well-Known Member

    That would've been/was my first guess.

    But the city(suburban) mpg's come pretty easy with the CVT... just drive the car normal/gentle and I'm getting 45+, ... I kind of have to think about it .. work a little for that with the 6mt. So I'd think if it was the CVT (transmission losses) that was causing the mpg loss , it would show at low speeds/ accel-decel- as well as on the highway.

    So another guess would be that maybe Honda sacrificed a little mpg on the higher speed (highway) by letting the car lug on the turbocharger in order to keep the rpm walking down -- so the driver doesn't get as much "rubber band" sensation on rolling hills on the highway (?_

    /the car doesn't have much of a "boost gauge" (11 bars I think, and I almost never have it displayed),... but I did notice that (I think) I'm hearing the turbocharger work a little more with the CVT car
     
    Last edited: Aug 7, 2018
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  17. Carcus

    Carcus Well-Known Member

    Update on the CVT (vs MT)--

    Highway mpg -- (imo) -- It's the lower rpm's (read cvt transmission computer control), resulting in increased turbocharger use that drops the mpg about 6% on the highway @ 70 mph, more at 65 mph, and probably not much of a difference at 75 mph. I would imagine the discrepancy between 6mt and CVT would be larger in rougher conditions (cold, strong headwind).

    City mpg -- advantage CVT here, put the car in eco (which I think helps keep it out of the turbocharger) and drive normal/conservative -- the CVT is quick to pick the right ratio --- it's easy to get mpg well above EPA rating (i.e into the 40's)

    /all this is based off of an iFCD comparison (no calibrated scan gauge), so ..take my results with a grain of salt
     
    Last edited: Aug 7, 2018
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  18. RedylC94

    RedylC94 Well-Known Member

    It would've been easy to program the CVT to do a better job picking the right ratio than than the average human driver does. I still suspect the mechanical efficiency of CVTs is lousy, compared a manual, or even a modern step-shifting automatic.
     
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  19. Carcus

    Carcus Well-Known Member

    Well, that's what I thought before I drove this one for a couple days.
    A quick search says the metal belt pusher type cvt can exceed 97% efficiency -- much better than the old belt type cvt's:


    "Variations in the hydraulic pump displacement that are determined by the required ratio adjustment dynamics show that with a sufficiently small pump, peak efficiencies exceeding 97 percent are possible."
    Maximum Transmission Efficiency of a Steel Belt Continuously Variable Transmission | Request PDF. Available from: https://www.researchgate.net/public...Steel_Belt_Continuously_Variable_Transmission[accessed Aug 07 2018].

    Figure. 13 Calculated transmission efficiency of metal V-belt with FEM pulleys
    http://www.simulia.com/download/pdf2010/Saito_SCC2010.pdf

    Your Next Vehicle Is More Likely To Have A CVT: Here’s Why
    https://www.washingtonpost.com/cars...a1863229397_story.html?utm_term=.44b3c8af8caa
     
    Last edited: Aug 7, 2018
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  20. Carcus

    Carcus Well-Known Member

    High speed highway, 87 E10 vs 93 E0

    A couple of long highway trips, both targeting 75+ mph, similar winds, temps in mid 40's.
    87 E10: 39.9 mpg
    93 E0: 44.5 mpg

    so a 10%+ difference

    (these are hand calculated numbers at the pump)
     
    Last edited: Jan 3, 2019
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