Triple challenge

Discussion in 'Start Your Journey Here' started by SentraSE-R, Dec 1, 2008.

  1. SentraSE-R

    SentraSE-R Pishtaco

    Thanks Sean,

    That explanation of open v. closed loop makes sense. Has anyone done any research on whether the OBD-II learning affects our mileage? If hypermilers train their OBD-II brains to expect us to run in open loop the majority of the time, does that affect the transitioning to closed loop?

    I did take your FAS key off advice, and let my idle speed drop to 1000 rpm before keying off. After I pulse, my rpms plateau at 1300 rpm for a few seconds, then drop to 1000 rpm. That's when I key it off. Idle is at 700 rpm, but I haven't waited for the engine to drop that low. I think I'd be ready for another pulse by then.

    I can't wait to see how my wife's AT Elantra handles our upcoming Christmas trip. It got 38.5 or 38.6 mpg over 800 miles on cruise control at 55 mph to my mom's this Fall. I'm hoping for about a 5-6 mpg improvement this trip, hypermiling. There doesn't seem to be much I can do with it other than substitute NICE-on for FAS, and DWL and DWB. P&G for 400 miles each way seems like a lot of work, and potentially hazardous with the high-volume Christmas traffic. I see about 8-10 mpg improvement in my MT car hypermiling over cruise control, so 5-6 mpg seems doable with an AT auto.

    I like your hypermiling to chess/billiards analogy. I'm a decent chess player, and have played enough billiards to know what to do. A college friend held the student union title for several of the table games. He could play opposite-handed, and beat me. I learned a lot from him.
     
  2. SentraSE-R

    SentraSE-R Pishtaco

    Well, I waited until the rpms dropped to my idle speed of 700 rpm after pulsing. It's not that far after the 1000 rpm plateau. After pulsing, and the shift to neutral, the ICE plateaus at 1300 rpm, drops to a 1000 rpm plateau, then drops to 700 rpm idle speed. So I'll try that on my next P&G test.

    I filled my gas tank today, and it took nearly a gallon more than predicted by my SG, about a 16% error. I didn't recalibrate my SG this time, as the fill level at auto pump shutoff may be the problem. It also fits with my SG's performance in the past. It seems to overestimate city driving when calibrated for highway driving, and it underestimates highway driving when calibrated for city driving.

    I drove miles on the freeway in open loop, and my car took forever to enter closed loop. On another part of the drive, my car entered fuel cutoff well under 2500 rpm in 6th gear - at about 1600 rpm. Time to throw some of my suppositions out the window.
     
    Last edited: Dec 20, 2008
  3. SentraSE-R

    SentraSE-R Pishtaco

    Well, today I filled the tires on my wife's car in preparation for our 800 mile roundtrip Christmas trip to my mom's. They're only rated to 36 psi. While I was at it, I filled my car's tires to 51 psi, since that's their sidewall max pressure. The last time I filled them, I inflated them to the recommended 44 psi. I was shocked to find they had all dropped nearly 2 psi/month since my last check in May. I've been getting suboptimal mileage all summer. I wonder how much better my mileage would have been had I kept my tires inflated to their max over the past 4800 miles? I think I'll be making a trip down to Monterey soon to check my mileage and handling with the properly inflated tires.

    I'm expecting over 40 mpg with her AT Hyundai Elantra, since I got 38.6 mpg with it, using cruise control at 55 mph. 40.5 mpg would be 150% of the car's EPA combined estimated mileage, and would put me into the Elite Hypermiler ranks for driving her car. 45 mpg would make me ecstatic.
     
    Last edited: Dec 24, 2008
  4. SentraSE-R

    SentraSE-R Pishtaco

    My mileage results driving my wife's Hyundai Elantra last week disappointed me. I drove most of the 800 miles with cruise control set at 50 mph, and used NICE-on during the major downhills. Despite my efforts, I only got 39.6 mpg. My biggest mileage killer was driving the pre-dawn hours in the dark with headlights and windshield wipers on (rain sprinkles and fog in the morning). The car's average trip mileage never rose to an indicated 40 mpg before our morning rest stop. After that, I was able to push it to an indicated (and optimistic) 42-44 mpg on the uncalibrated SG. SG calibration ended up at 13.5%.

    I guess I should actually be pleased that my results weren't worse than my Fall mileage results, since temperatures were probably 20ºF cooler this trip, and I was powering my headlights much of the time.
     
  5. SentraSE-R

    SentraSE-R Pishtaco

    I found my car's P&G sweet spot today. Using the SG pulled from my wife's car, and resetting all parameters back to my car's, except for the 13.5% calibration and my engine size increase to 3L, I ran 3 tests. First was a cruise controlled lap (1/2 of my 19 mile test route). It came out 45.8 mpg, compared to 39 with its previous calibration. I can't remember if the previous value was with an uncalibrated SG for the 2.5 L engine, or using some earlier calibration figure, but as a baseline, my current trip average mileage value is about 15% high. Then I did a lap pulsing in 4th gear from 25-40 mph, and got 61.2 mpg. I backtested with my previous 5th gear 35-50 mph P&G regimen, and got 50.4 mpg. My previous best with the earlier calibration was 46 mpg, so today's value is about 10% high compared to earlier efforts. Allowing for a 15% high estimate, I'm still getting better than 50 mpg with this new P&G regimen.
     
    Last edited: Jan 9, 2009
  6. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Now you're talkin'!! Looks like it matches up pretty well with what I see in my Elantra (see post #39 on this thread to refresh) I'm guessing your gearing is pretty close to mine if you're seeing those numbers. :)
     
  7. SentraSE-R

    SentraSE-R Pishtaco

    Yeah. I'm stoked. I almost wish I had my old daily commute with my carpooler again so I could play the mileage game. As it is now, I hope for sunny days and an excuse to take the car out for a drive, so I can experiment with different techniques. When I go to the bank now, I park a block away, at the top of a block long downhill, so I can get a free block and a half of zero gas used. When I drive home, I can roll 2-1/2 blocks around two corners to end up parked in front of my house. Driving to my wife's office earlier this week, I drove about a mile and a quarter of 17 mpg driving to get to the top of a hill, and I coasted the remaining 1-3/4 miles to her office, getting nearly 37 mpg for the total 3 mile trip.
     
  8. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    My friend, you've been bitten by the bug! ;)

    (Nice scope, by the way -- what's your favorite celestial object?)
     
  9. SentraSE-R

    SentraSE-R Pishtaco

    Thanks, as always, Sean. I appreciate your encouragement and the advice I've received from the members here. I could have saved myself a lot of trial and error if I'd listened to you and tried your Elantra P&G regimen. I just figured Wayne's review of the Toyota Corolla XR5 made it sound really close to my car in performance and engine size, so I'd try his P&G routine.

    It's difficult to pick a favorite celestial object, because I have favorite double stars, favorite galaxies, etc. My favorite object is probably Messier 42, the Great Orion Nebula, because it's full of amazing detail. Following is a photo I took of it with another of my scopes. If I lived in the southern hemisphere, the Eta Carinae Nebula would probably be my favorite.

    [​IMG]
     
  10. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    :) You learned more the route you took. ;)

    Good choice! That's a lovely structure -- and not bad for photography, either! What did you use for tracking?

    Mine's the crab nebula. :)
     
  11. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    For the record, what was the routine you used first, that didn't work so well?
     
  12. SentraSE-R

    SentraSE-R Pishtaco

    I stacked a series of short (90 second) exposures, so I didn't have to autoguide the mount. It's a Losmandy G-11.
     
  13. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    I'm impressed!
     
  14. SentraSE-R

    SentraSE-R Pishtaco

    What didn't work for me compared to a 39.0 mpg cruise-controlled baseline was:
    40-55 mph deltas in 6th gear with aggressive LOD of 80-90% (38.4 mpg) - a net loss

    What didn't work very well (~4% improvement)
    10 mph deltas, pulsing in 6th gear from 35-45 mph (41-42 mpg v. 39 mpg with cruise control)

    What initially worked were:
    35-50 mph deltas in 5th gear (40.5-44 mpg) - a 4-13% improvement

    Above tests were with 38.5% SG calibration. Then I reset the SG to default and started over again with my engine size, speed correction, etc. After a roundtrip to Reno, I ended up with 28.5% SG correction. Using the new correction, I started maximizing my glides, and raised my 18.8 mile test route's mileage to 46.2 mpg, with the 10% lower correction factor, and pulsing from 35-50 mph in 5th gear. With the easier correction factor, my real mileage is probably still about 44 mpg.

    Unfortunately, I changed parameters again, having put my SG in my wife's car for a Christmas trip. This week's tests changed tire pressure from underinflated 33 to 51 psi, increase in indicated engine size from 2.5L to 3.0 L, and the 13.5% SG correction factor that I used in my wife's car.

    That changed my current calibration cruise control run mileage to a highly optimistic 45.8 mpg, about 17% higher than the original 39 mpg.

    A 35-50 mph P&G regimen in 5th gear gave me 50.4 mpg, about 15% higher than my 44 mpg norm for my 5th gear 35-50 mph P&Gs. Again, this confirms my current calibration is about 15-17% too optimistic. It also confirmed this regimen is only 13% better than baseline.

    What worked best was a 4th gear 25-40 P&G delta, yielding an indicated 61.2 mpg yesterday, and 62.9 mpg today. Even allowing for a 17% optimistic calibration, that's still 52.3-53.8 mpg. 53 mpg is a 36% improvement over my 39 mpg cruise-controlled baseline, and triple the 13% improvement that my 5th gear P&G gives me. It's obviously my car's sweet spot.

    Interestingly, I tried a 28-40 mpg 4th gear P&G, which should have kept me within a 1500-2300 rpm range, but only got 57.4 mpg indicated (would be 49.1 mpg actual), or 26% better than baseline. Apparently there's enough coasting gain in the 25-40 mph delta to make up for the wasted gas accelerating from 1300 rpm to 1500 rpm (roughly 25-28 mph).
     
    Last edited: Jan 10, 2009
  15. SentraSE-R

    SentraSE-R Pishtaco

    My car really likes to go slow. I reset my SG calibration to 30.5% temporarily until I get a better calibration figure with the SG set to a 3.0 L engine. This current calibration should estimate mileage slightly on the low side.

    I ran half of my test drive with cruise control at 35 mph, instead of 40. I got 44.7 mpg v. 39.0 mpg. Then I ran it with CC @ 35 mph in 5th gear, and mileage dropped to 41.7 mpg. One more CC run @ 35 mph in 6th, and I got 46.9 mpg while averaging 31 mph on all the runs.

    My car is also thirsty when pushed. I did an aggressive P&G between 25-40 mph @ 85-90% LOD, and got 53.5 mpg. A less aggressive P&G between 25-40 mph @ 74-82% LOD got 54.9 mpg, with avg speed 25-28 mph, respectively.

    I took the car on the freeway, with cruise control on a level stretch of highway for about 3 miles to the next exit and back, and got about my normal mileage - 38-40 mpg. Pending more calibration fine-tuning, the limits of my thirsty 2.5 L engine are becoming apparent.

    Highway
    72 mph CC = 26 mpg
    62 mph CC = 30-31 mpg
    55 mph CC = 38-40 mpg
    55 mph CC + FAS with lots of hills = 46 mpg

    Stop and go
    40 mph CC (35 mph avg) = 39 mpg
    35 mph avg P&G = 44 mpg
    35 mph CC (31 mph avg) = 45 mpg
    28 mph avg P&G = 54 mpg

    This weekend I'm taking my wife's AT Elantra to the Central Valley w/550 lbs of people loading it down, and taking a friend's MT Toyota Corolla to Monterey w/a similar load (the car is so full of junk, the suitcases will have to go on top of the junk in the back seat). The Corolla may surprise me. The Elantra won't.
     
    Last edited: Jan 13, 2009
  16. SentraSE-R

    SentraSE-R Pishtaco

    I may be nearing the end of my parameter testing, as I think I've tested different P&G regimens thoroughly and found them repeatable. Today, I eliminated 26 mph 4th gear cruise control, narrow delta low speed P&G, high speed P&G, and high speed P&G NICE-on.

    I tanked up again, and got 47.2 mpg over 174 miles, excellent mileage considering the cold temperatures and the fact I was experimenting with mileage techniques. My SG calibration is 24.8, only 1% below what it was when I had the engine size set for its actual size of 2.5 L.

    26 mph 4th gear was in the low 40s over about 1/3 of my test route, so I aborted the run. It was going to be below my 45.8 mpg baseline at 35 mph in 6th gear. I switched to a low delta P&G between 25-30 mph, and got mid 30s results. Again, this was not fruitful, so I aborted the test.

    I ran 1/4 of a test drive with CC @ 40 mph in 6th, and got almost 45 mpg. Apparently today's warm weather and my inflated tire pressure of 51 psi helped raise the baseline today

    A full 9.4 mile half run with my 25-40 mph P&G regimen got me 59.0 mpg, my best completely calibrated test drive.

    Normally, I run these tests on a frontage road paralleling a highway. Today I ran a parallel round trip on the highway at 55 mph in cruise control, and got 39.0 mpg, which is consistent with my thousands of miles of freeway driving last summer.

    Then I reran the test with high speed P&G, pulsing from about 50-65 mph using 6th gear. The results were 40.2 mpg. That's slightly improved, but only a 3% improvement over straight cruise control.

    On the way to the start of the highway loop, I tried high speed P&G NICE-on, and got poorer results than the two other freeway tests..
     
    Last edited: Jan 14, 2009
  17. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    You should be able to do better on the highway than that, but HS P&G is a very finicky animal. Basically, you have to keep the trip average up and watch it like a hawk to ensure that the end of every glide leaves you with a higher number than the end of the previous glide. At those speeds it is very difficult to get the right pulse rate and the margin of error is very small indeed. Any inattention and you'll get worse mileage. I use NICE-ON for HS P&G and at the speeds you are quoting I can usually manage 53-56mpg on reasonably flat roads. I don't like to drive that fast, but it is doable. I would guess that with your car upper 40's should be possible.

    Heck, over the summer I drove an Acura TLS with its monster engine and 6spd, used P&G with FAS at the speeds you've listed while using 6th and I got 43mpg out of it over ~22mi. This was with huge chrome wheels, super wide and sticky tires, spacers behind the wheels, and every gadget you can think of weighing that thing down. I was also working with a gentle uphill for about 3/4 of that trip as well.

    Keep trying -- I think there's more in there for you.
     
  18. SentraSE-R

    SentraSE-R Pishtaco

    Friday's trip was actually just around the bay, about 120 miles total, in my wife's car. I forgot to recalibrate speed, which was 3% off. Mileage was about 38 mpg indicated, down a little from my 39.1 mpg average, and my 39.6 mpg best with her car. It was a relatively sort trip, and we had a 300 lb. passenger, so all-in-all, I was satisfied with my results.

    Now I'm in Monterey, driving a friend's 2007 Toyota Corolla MT, which is EPA rated 28/37 mpg city/highway. I got about 48 mpg indicated before our first morning break, and about 52.5 mpg after the break. Piddling around birding with lots of stops and gos got me about 43 mpg. The limits are so much higher with Casper Milquetoast engines ;)
     
  19. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Nice! I'm enjoying your progress. :thumbs_up:
     
  20. SentraSE-R

    SentraSE-R Pishtaco

    Final mileage for the Monterey trip in the Toyota Corolla was an actual 413 miles on 9.524 gal = 43.4 mpg. I forgot to write down the SG's tank estimated gallons used before erasing it, but the SG correction factor would have been a guess, anyway. My friend filled the tank about 25 miles before I started driving her car, and she didn't reset the trip odometer on the car, but she does log her cumulative odometer reading. I reset the trip odometer early in the morning of the first day of the trip. it and the SG showed 374 miles traveled on the tank, and the SG showed about 8.6 gallons used, IIRC. Adding another 37 miles traveled, and another .9 gallon of fuel used, the SG correction factor and mileage attained would have both been very close to the SG's values observed.

    My stop and go birding hurt the trip mileage considerably. My initial impression was that the Corolla's trip mileage wasn't that much different from my best tanks on my SE-R, but closer examination reveals the truth. Indicated highway mileage with the Toyota was about 50 mpg, while my Nissan might get 40 mpg under the same highway conditions. I tried most of my bag of tricks with the Corolla - everything except establishing a P&G routine for local driving. The 10 mpg better highway mileage with the Corolla indicates i would have gotten about 33 mpg with my Nissan on the same trip driving the same way - not an unreasonable assumption, in hindsight. I know I can increase my car's local driving mpg over 50 mpg with P&G, but I wasn't using it with my friend's Corolla.

    When my friend finds the time, she'll call me with a couple of her recent tank miles and gallons figures, and I'll have a better guess on whether my hypermiling made much difference. There's too much variability in drivers, % of city/highway mix, etc., but at least I'll know if I beat her typical driving average mpg. I sure hope so. I'd like to have something to show for the anemic performance of the Toyota's 1.8 L engine. Accelerating in it felt a lot like driving a car attached to a slingshot - mushy and weak.
     
    Last edited: Jan 20, 2009

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