Kickin' it up a notch

Discussion in 'Start Your Journey Here' started by Bruce, Jan 17, 2007.

  1. diamondlarry

    diamondlarry Super MPG Man/god :D

    Wayne, It probably won't be me anytime soon. All I can come up with is:WOW! That is some great detail. It kind of inspires me to go back through my route and see if there are any areas I can improve in.

    Bruce, If you don't mind, I think I may adapt your method of reporting segments ie, A,B,C, etc. Much less typing. :)
  2. Bruce

    Bruce cheapskate

    Thanks for the comments and compliments, all.

    psy - yeah, there appears to be a no-man's land for steady state between 4th
    unlocked (~27-30) and 4th locked (~44 MPH), FE-wise. It seems better to
    hang out at one or the other but not in between, at least when cruising
    without FASing. 4th locked appears to have a slight edge, at least on the
    iFCD (50-60 MPG vs 40-50).

    I was struck by your comment in one of your Okie FAS videos that the
    Civic wouldn't FAS quite as far as the Accord, which makes sense...the
    Accord weighs about 500-800 lb more and probably has comparable
    rolling/aero resistance, and coastdown times would be a function of the
    weight per total friction. It goes against all recommendations for
    maximizing FE, but I'm tempted to try adding 500 lbs just to see what it
    does for glides and DWL. I know my wife's Saturn LW300 sure keeps its
    momentum a lot better over small hills. Of course, all this goes up in smoke if
    I use the brakes at all, but I can DWB nearly all of my commute.

    At this point, I'm still in the other direction -- nothing in the car, and I
    pulled the rear seat to knock off another 50-100 lb.

    If I could increase the glide times, I'd be more likely to use them on
    flats or uphills. Right now, I can't get a glide long enough to be
    worth a FAS unless it's on a downhill. Warm weather will help this
    somewhat, since it'll reduce rolling and aero losses, so I expect I'll
    be able to FAS in a lot more places once the temperatures warm up.
  3. psyshack

    psyshack He who posts articles


    Don't add weight to the car. Maybe just use the dainty wife and children for a test. ;) The Accord is a coasting machine. I don't think Ive ever seen a car that coast as good as the Accord. Now the Civic on the other hand is awful. Throw in a head wind,, and your wasting time and effort. ( for me anyway )

    As a motorcycle rider at times. Ive become very aware of road surface's. There is a campaign in Oklahoma to build the cheapest uneven roads that can be had. Then if its concrete. They come back over it and grind it level and leave these tiny little grooves that run with the direction of the road. Make the ride smooth but increases rolling restence like a mofo. Its truly awful. This has ruined alot of my FAS'ing on some of the hwys. If its not a concrete road and asphalt. They use the course's cheapest stuff they can find. The effect is the same if not worse. I cant change my route much. Get very far off the beaten path on my daily grind and travel times double. And I'm not xcel.... LOLOLOLOLOL.

    Maybe load driving will be your savior?

    Good work

  4. Bruce

    Bruce cheapskate

    After a few days of expressway driving this week, I tend to think you're right. It certainly works a lot better on unfamiliar roads.

    On Tuesday, I was driving between facilities on an expressway that was mostly flat except for long notches where it crossed under cross streets. I'd accelerate to 60 by the edge of the downhill, FAS down the hill to 50 by the time I hit the bridge, hold speed up the hill until I hit 55 again, then go to a constant TPS. With all the extra pulsing that was required, I have a hard time believing I came out ahead over just holding constant throttle through the dip.

    After some more time on the expressway, I concluded a FAS wasn't worth the bother unless I was on a downhill steep enough that I was getting up to 60-65 MPH at very light throttle, in which case I wouldn't mind bleeding off some speed anyway.
  5. Bruce

    Bruce cheapskate

    In another thread, Wayne wrote:

    Which raises an interesting question: how did you determine that this speed and gear would maximize fuel efficiency on an extended climb, and how can I do the same in my car? In other words, is it possible to use the iFCD information to maximize fuel efficiency in real time on an extended climb, and if so, how?
    Last edited: Feb 24, 2007
  6. xcel

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

    Hi Bruce:

    ___You have been doing some research, haven’t you ;) One of my own personal unwritten rules when driving an IMA equipped Honda hybrid is to stay out of assist at all costs. This is not so much a FE issue but a pack longevity issue. If there was a pack that was going to last 15 + years, the Little Red Beauty’s was the one. A side effect is the FE got stupid quick … I would also never run one so high so as to engage VTEC up or around 3,000 - 3,250 + RPM’s either as that was not only a waste of an ICE, it was a waste of fuel.

    ___Since this was my first and last real climbing experience in her, I was going to do my darndest to maintain her current 104 mpg average while crossing the country for my last drive and was working out these things in my head with the iFCD feedback guiding/leading the way. In the manner described, she would hold 50 + mpg during the climb while I could double that by FAS’ing a similar distance down the backsides of each of those monsters out east. As long as there was a truck lane, I was repeating this over and over until I finally reached my destination about 40 miles from the coast. IIRC, I increased her FE from 103.8 to 104.x when I arrived using the method as described through those mountains?

    ___Good Luck

  7. Bruce

    Bruce cheapskate

    One other question...I've been told that acceleration to a steady state speed and acceleration in a pulse require different rates for optimum FE; slower is better for steady state, whereas an engine load of 70-90% is optimum for a pulse.

    Why is that? The engine consumes the same amount of fuel for a given acceleration rate, so why wouldn't a single acceleration rate consume the least amount of fuel, regardless of application?
  8. xcel

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

    Hi Bruce:
    ___You have been told this? Where did you read that ;)

    ___Three things … Remember a P&G releases the ICE from any duty as well as any fuel consumption on the back side in a FAS/EV-Glide/Glide but it is absolutely imperative you receive the maximum glide distance w/ no fuel consumption to make it work properly. Accel fast into a back up and you just accelerated at 2 - 10 mpg and then threw it all away while hitting the brakes to come back down. The slow and steady would have yielded a much larger buffer in which to FAS or slow in fuel cut back down … Second item. A slow increase keeps FE at a higher rate until the slower speed steady state speed is reached. A higher load pulse is burning fuel like mad but you are burning fuel during the steady state cruise also which is completely different then a P&G. See Tarabell’s HCH-II article for proof of concept. There is no non-fuel consumption portion and the high load/extremely poor fuel consumption just never gets made up. Third item. ICE and drivetrain wear. Accelerating with a higher load pulse is putting the colas to the fire so to speak. There are high forces seen throughout the drivetrain and those forces are not kind to any of the components that see the higher loads. Think an all-city taxi cab vs. an all highway delivery service driver. Which vehicle would you like to purchase used with 100K on the ticker? The all-highway miler of course just do to the fact it was mostly steady state highway cruise vs. the continuous cycle of an all-city like daily grind. I HS P&G the Accord but my accel’s are usually in the 2,100 RPM range (sometimes a bit more but not much) with glide distances that can be scary long. For longevity, take it easy and she will pay you back in dividends time and time again.

    ___Finally, with your SG-II, go do the test runs similar to those designed for Tarabell. P&G is just a completely different animal then accel’s to a steady state cruise. In your Prism it may work out differently but it doesn’t in the non-hybrid Accord, Ranger or HCH-II.

    ___Good Luck

  9. Bruce

    Bruce cheapskate

    :) I was too lazy to hunt down the quote, but I'm sure you can guess. :)

    I agree that lower accelerations have a better chance of success and have been using the lowest throttle settings that will get me to a target speed lately (7% to 30 MPH, 9% to 45 MPH); max RPM's have been under 2100-2200 for most rides. I still haven't had a chance to do any acceleration testing.

    One other the last oil change, I put in a quart of 5-20 and three of 5-30 (all Mobil 1 synthetic) because that's what I could get locally. The manual recommends 10-30, 5-30 or 0-30 depending on weather conditions. I've mail-ordered a bunch of 0-20 and 0-30 Mobil 1 for the next change, and am considering a 50-50 mix. I'm a bit concerned that I'd have insufficient journal pressure and some blowby (the engine's at 112K) if I threw in straight 0-20. Any thoughts, recommendations or experience with a similar setup?
    Last edited: Apr 9, 2007

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