Arrgh! Summer Mileage

Discussion in 'Honda Hybrids' started by jmelson, Jun 23, 2009.

  1. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    I personally am used to the heat (grew up in SC), but the Insight mostly isn't. It did go through some 100+F days last summer and worked just fine -- though assist happy.

    It is good thinking, but any charge/assist cycling should show up on the display. I'm seeing similar sluggishness in my Insight but in that case I know it is charging because 1) my Calpod disabling switch gets me back to normal operation -- something I unfortunately didn't notice until right at the end of my trip home yesterday and 2) the car never reaches 20 bars no matter how much regen I use. I'm going to do a 12V pull to force a full recalibration event -- the computer seems to be confused.

    Speaking of which, Jeff -- does the car still perform better in the mornings when it is cooler? Mine does not so it makes sense to go after the computer -- how about you?
  2. psyshack

    psyshack He who posts articles

    I don't think so unless the car has a stealth agenda concerning regen. I work very hard to stay out of the pack for the most part except when it comes to pulling hills and some lights when traffic is stacked up and folks are fuming behind me. <<< That is when fake shift can be your friend IMO. And honestly,,, i don't glide the car like I thought I would. I get some free regen then look twords SAMBA. Even with assit extending glides the car is no where near as good as the Accord in a full blown fas, Civic or MZ3. It's glides even using assit are about on par with the Ranger in a fas. Really pretty sad IMHO. And a fas in my book is worthless in the car.

    I have been wanting to do some coast down testing in the HCHII and tie it to this data.
    And this.

    I will do the test in full fas mode and glide / assist.

    It is to my surprise taking me longer to figure out this car than I would have ever thought. And honestly there have been some emotional and mental road blocks along the way. As of late I've went from flipping the CVT input device off and wanting to put my fist through the Navi screen or just flat out pulling over and walking. To yelling the Serenity Prayer when my frustration level with the car peaks. :)
  3. psyshack

    psyshack He who posts articles

    Car is great in the cooler mornings. Normal as a matter of fact. Assist regen ratio hasn't seemed to change a bit. And honestly I have not heard the fan run a lot cooling the electronics. It has it's own little sound. The wife can even hear it. It's most notable after a hard glide regen or a hard assist. Then its gone. Which is really rare when I'm at the wheel. I like to see that pack full and stay up there. So I tend to drive for the pack and all that it brings. Also I have yet to see a recal or a hard forced regen in the car. I've explained the behavior and reality's of such actions taken by the car to the wife and she reports not seeing one either. Maybe today will be the day as she will be driving back from Stillwater in the heat of the day. They are forecasting record heat today, between 102 and 105 depending on were your at. There is a slight breeze out of the south today. But the wind should not affect the wife much today as she will be traveling in a eastern direction with the lay of the land diffusing some of that for her.

    When she gets home I will get in the car with it hot and take it out for a spin and look at the IAT. Then check them tonight after it's cooled down a bit.
  4. hansonclan

    hansonclan Member

    My car is behaving the same as psyshack's. It operates normally in the morning, but the drive home after a 100F+ heat soak is difficult. Almost every day I get a forced charge, even when my SoC is 5+, it seems to take forever with a 2-3 bar forced charge for the SoC to increase, and then the SoC suddenly increases to 8 bars which, until the last few weeks, I had only seen once before - usually 7 is max. Sometimes the SoC will drop to 1-2 bars (as in a recal) shortly after the forced charge begins, but normally not. Very frustrating, because to me it doesn't appear that my battery needs a charge, but it's force charging anyway. Also, it seems reluctant to accept regen, i.e. in a situation where I might normally see full regen under braking, I only see 2-3 bars.

    This behavior is different from last summer's when I would get about a weekly recal, i.e. SoC drop to 1 bar, forced charge brings SoC back up to 7 bars within a few miles. A/C use would almost guarantee a recal.

    I can't explain why the car is behaving differently between last summer and this, except that the dealership may have squirted a software mod when I had the oil changed last month. It does seem though that this car doesn't really like the heat (or cold, for that matter).

    Having said all that, I am currently on one of my best tanks - 64.8mpg indicated, 575 mi on this tank so far with 4 pips remaining. It acts a little funny in the heat, but it's still better than the cold.
  5. ALS

    ALS Super Moderator Staff Member

    Based on the original post and the experts on HCHII input I feel you are getting about the right mileage you should be getting using E10. Based on testing by members on this board most have seen a drop between 8 and 12 percent using E10 over regular straight gas.
    Lets say using the E10 you see a drop of 10% your cars EPA rating to 40.5 mpg.

    The EPA tests their cars at 60-70 degree air temperatures and use pure gasoline.

    It's easy to beat EPA numbers at 60 mph if your running "straight gas" and the temperature is under 70degrees.

    I know it is frustrating not to see 50 plus mpg on a regular basis but you have two variables beyond your control working against you. If your seeing high forties at the pump using E10 then your doing well. Don't trust the on board factory display. Others have already warned you on their inherent inaccuracy.

    My 960 Volvo gets 29.25-29.75 mpg highway at 65 mph on straight gas. I'm lucky to see 27 mpg on E10 on the same route and speed.
  6. jmelson

    jmelson Well-Known Member

    I got up to about 56 MPG on the last full tank with my 2008 HCH-II that got wrecked. That wasn't as hot weather as we're having now, and I'm sure that has an effect. That was using E10, the only stuff we can get here. I've never gotten better than 52 MPG on the first part of a tank with the 2009 HCH-II, and am now getting 46-47 MPG per full tank. The trip fuel consumption display has been quite accurate on both of these cars, certainly always within 1 MPG of the calculation from the pump.

    The problem with St. Louis is it has a short fall and a REALLY short spring. Some years, spring is just one day between winter and summer! This year it was a bit more gradual.

  7. psyshack

    psyshack He who posts articles

    Hello all

    I did get a chance Sunday to do some testing. The heat wave was broken Sunday. We got a weak cold front come through thank goodness. The wife did not get home until late Saturday night. So no testing was done at that time.Here is how the test went off. I drove from our home in Okmulgee south to Henryetta and back. The round trip is 25.9 miles. I ave. both going and coming. First trip was on a cold engine with no A/C, second trip was a hot engine with A/C. Ambient air temp was 87f. A/C set to Auto 82f, recirc on.

    No A/C: 63.7 mpg, IAT 55-60 mph 94f, 30-45 mph 102f, Ave. speed 44 mph. SoC 6-7 bars.

    With A/C: 58.9 mpg, IAT 55-60 mph 98f, 30-45 mph 105f, Ave. speed 44 mph. SoC 7-8 bars.

    These numbers will be my baseline and referenced when we get some very hot summer temps in the future. The A/C hit was 4.8 mpg on this test. Safe to say a 5 mpg hit. This I find to be just a tad high. The hit in the Ranger, Accord, R-18 Civic and MZ3 are right at 4.0 mpg

    Also of note the No A/C test was run with the two front windows all the way down. The With A/C test was run with the windows up and the car completely buttoned up. If you put a lot of stock in aero, then the mpg number with no A/C could of been higher if I had ran with the windows up. Windows up for all the testing might have shown a larger delta between the two.

    Temps might climb up to the higher 90's today. Will just have to see. But no 100 plus temps expected for at least a week or better. I also came down with a stomach bug Sunday night and its still running it's course. It hit the wife last night. So we are both feeling poorly right now and off work.

    We will be waiting on higher temps here and to get feeling better.
  8. msantos

    msantos Eco Accelerometrist

    Hi Jeff;

    You were obviously running the AC very conservatively and with a steady foot, otherwise I suspect the MPG hit would have been a bit higher than 5 MPG.

    That is the thing with these cars (including the Prius). After all is said and done , it remains a game of minimums where even the slightest deviation in variables will cause dramatic differences in the MPG results. Its like an acrobatic act on the high rope. The higher the rope, the more significant the tiniest breeze will become.

    Also on this note, the higher the baseline MPG the greater the amplitude of the perceived loss (a 5% loss in a 50MPG car is not the same as a 5% loss in a 25 MPG car).

    Anyway, for as bad as summer can be, you have to wait for winter to show how truly dramatic the FE swings can be in this car. :eek:


  9. jmelson

    jmelson Well-Known Member

    Just a followup - We have had most of a week of cooler weather and the mileage has been creeping up. I am up to about 48.3 MPG so far. So, the past week's heat was definitely a major factor in the crummy economy I was getting earlier. Still, I'd like to get over 50, but it seems pretty hard to do.

  10. jmelson

    jmelson Well-Known Member

    Another followup - how long does it take the engine computer to remap the mixture tables after you change fuel grade? I live in an EPA enforcement area (St. Louis, MO) so I can only get E10 or other oxygenated fuel here. I took a couple of road trips in the past months and probably got pure gasoline while there. Then, arriving back in St. Louis, I had really LOUSY gas mileage. It looks like a dip of 5 MPG, from a normal of a little better than 51 MPG down to 46 or so.

    The ONLY thing that has changed is time - driving habits, speeds, temperatures, etc. have not changed much at all, but mileage has suddenly started creeping back up in the last week. So, it seems like maybe it takes ~750 miles for the computer to readjust the mixture after going from pure gas to E10.

    The only other car I ever had that showed something like this was a 1986 MR2, my first fuel injected car. (An awful mileage pig, by the way, due to insane "performance" gearing.) I actually took it back to the dealer after a fuel change due to rotten idling, engine shutdown at idle, etc. They correctly diagnosed it as change in fuel type, it took most of a tank to recalibrate, then ran fine.

    So, has anyone else seen this, a temporary poor mileage condition that corrects itself after about a tank and a half when changing back to E10?


  11. psyshack

    psyshack He who posts articles


    Our HCHII has only had one tank of booze gas in it. And that was the dealer tank purchased at QT. Only real gas since. The second tank was about 3 mpg better than the first. That is easy to write off to the car breaking in and us getting use to it.

    But,,, I have had booze gas in the 05 Accord, 06 Civic and the 07 MZ3. All three of those cars showed a 3 to 4 mpg hit as soon as you started driving. The 06 Civic loved premium in the winter. But floundered on it in the summer.

    Most modern cars adjust very fast to fuel changes. As for the Yota you had. I bet there was some water or other trash in the gas that caused the issue's.
  12. jmelson

    jmelson Well-Known Member

    Well, I came back from a road trip where I am pretty sure I got pure gasoline. I had AWFUL mileage on the first tank after I got home, around 46 MPG for the whole tank. Next fill-up I started out getting about the same poor mileage, and then when about half the tank was used up the mileage started to improve, going from 46 now up to 51 MPG and still rising. This is with E10 here at home. I can't detect any change in other conditions that might have caused it (driving style, tire pressure, temperature, route, etc.)

    As for the '86 Toyota, it did it enough times that I'm pretty sure it wasn't water, just that the computer didn't adapt well to fuel type change.

  13. ematzen

    ematzen Well-Known Member

    Hi Gang - I'm new to this forum also. Good thread. I just purchased a used 2006 civic hybrid and have been averaging 36.5 MPG or so. Mostly city driving, I live in Houston, so AC is always on. Although I am interested in maximizing mpg, I am also interested in being comfortable, so the AC is set to 76. It's HOT in Houston.

    Tires are filled to 40psi. The charge/assist seems to be working correctly, and I am getting comfortable with the process.

    Any idea if my 36.5 is unreasonably low? Anything I should do? I just changed the oil to mobil 1 0w20. I think the last oil change was a little over-filled.

    According to the dealer, the car has received all the appropriate updates.

    Any thoughts?

  14. Dream'R

    Dream'R Well-Known Member

    Welcome, EMatzen!

    In case you haven't yet read the "sticky" by Msantos about optimal use of your A/C, start there. Another valuable guide is Tarabell's report linked to the home page.

    There are a great many factors which affect your mpg. Hot weather adds its own set of additional challenges.

    Extracting the most out of your HCH-II involves learning how to "glide" where you apply just enough pressure to the gas pedal to eliminate regen but not so much as you 'refire' the gas engine. The fuel consumption display (iFCD) will give you a clue and also the slight lurch you will feel when this happens.

    I would think that you will get to 40+ mpg fairly easily and approach 50 mpg when it cools off to the 70's.

    Good luck. You will learn a lot about your car from those who share their knowledge and experience on this site.
  15. Chuck

    Chuck just the messenger

    Also my 1st thought.

    Warm weather more than makes up for the E10 (or more likely, I use E10 year round)
  16. psyshack

    psyshack He who posts articles

    With my new SG in hand I can start testing again.

    My gut is telling me HCHII really does not like high or low ambient intake air temps. This morning as the wife and I left for work with the new SG setup at Waynes defaults. It was 66f. WTF is up with that for Ok. in August, WOW!!!!!! Within 1/2 mile the water temp was up to 178f and I had Auto stop at my first stop sign om less than a half mile. With in 3 miles the cooling system was cycling at 205f. And intake air temp was at 89f. After 5 miles it was 30f above ambient temp.

    I wonder if HCHII and think about it a lot concerning intake temps. Would it work better with a CAI in the summer months and a WAI mod in the winter? From what I;ve seen it does not like to be baked like a real Insight mill, R-18 powered Civic or a K24 Accord......
  17. Kacey Green

    Kacey Green Well-Known Member

    Mine does best in 70 to 80sF anythig in the 60s or below is bad MPG the 90s and above are decent but I start thinking about AC and the numbers are already down so whats a little electric AC...

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