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Discussion Starter · #41 ·
I don't think I would have the patience to drive 800 miles at 60 MPH or slower unless I was on seriously twisty back roads. In that case I wouldn't be watching my fuel economy because I'd be having too much fun pushing the car's cornering limits.
 

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Discussion Starter · #42 ·
825 Estimated Range

Trip 5 of 27

Estimated Range Left: 676 miles
Driven: 149.3 miles
Estimated Total Range: 825 miles
Range buffer: 25 miles / 0.5 gallons
MPG: 54.5

No movement in the gas needle. I expect it to start moving on my way home this afternoon. At 140 miles on the tank the estimated range was 660 miles. Each mile I drive now with no gas needle movement will add to the buffer.
 

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Discussion Starter · #43 ·
835 Estimated Range

Trip 6 of 27

Estimated Range Left: 657 miles
Driven: 178.3 miles
Estimated Total Range: 835 miles
Range buffer: 35 miles / 0.7 gallons
MPG: 53.2

Still no movement in the gas needle. I expected it to start moving on my way home this afternoon, but when I went back an reread my post about 715 miles on a tank I noticed that I reported the needle starting to move at 250 miles. This means either near the end of the day tomorrow or on my way to work on Wednesday.

Here are the pictures of Trip 1 and the overall odometer from this afternoon. I have no idea why they uploaded sideways.

IMG_20130819_163856.jpg IMG_20130819_163904.jpg
 

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Trip 6 of 27

Estimated Range Left: 657 miles
Driven: 178.3 miles
Estimated Total Range: 835 miles
Range buffer: 35 miles / 0.7 gallons
MPG: 53.2

The more you drive the more your estimated rage goes up lol nice.
 

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Discussion Starter · #45 ·
Trip 6 of 27

Estimated Range Left: 657 miles
Driven: 178.3 miles
Estimated Total Range: 835 miles
Range buffer: 35 miles / 0.7 gallons
MPG: 53.2

The more you drive the more your estimated rage goes up lol nice.
Until the gas gauge starts to move, the range will fluctuate around 660 miles - higher in the morning and lower in the afternoon. It's a downhill drive in the mornings. Since the range is based solely on the average MPG until the gas gauge starts to drop, my estimated total tank range will continue to climb. At the rate it's climbing I might be able to hit 800 miles without triggering the low fuel warning system (light or DIC message).
 

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001.jpg 003.jpg 002.jpg You got me thinking about trying it also.. The second pic is almost from the day I picked up the car..Hopefully I can make it but traffic will play a big part...This little diesel keeps shocking me with the fuel mileage...I'll try for better pics an Friday... I have a feeling I'll see the low fuel light on before I make it home Friday..It's about 65 miles one way to work
 

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Discussion Starter · #47 ·
Sperry, you have to keep the average DIC MPG above 52 to have a shot at this. If you didn't fill into the fill pipe you have to keep the average DIC MPG above 54.
 

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Quick question, maybe a sillyone with an obvious answer;

When i slow to a stop or any time i slow, i down-shift. Are you just putting it in neutral and utilizing only brakes to increase mpg? and also (since you said your commute is downhill 1 way) are you also popping it into neutral and coasting as much as possible? Just curious how you are driving it.
 

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Discussion Starter · #49 ·
884 Estimated Range

Trip 7 of 27

Estimated Range Left: 676 miles
Driven: 207.9 miles
Estimated Total Range: 884 miles
Range buffer: 84 miles / 1.7 gallons
MPG: 54.2

Still no movement in the gas needle. I will be very surprised if my "Estimated Total Range" continues to climb at this point as I think I saw a hint of needle motion when I hit a bump this morning. I fully expect it to drop back to the 840-850 range. The afternoon trips give me a more accurate picture of how the car is performing. I do remember when I hit my 715 mile tank that once the needle started to move the reported fuel level drop was very linear with respect to miles driven and I have come to depend on this feature of this car.
 

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Discussion Starter · #50 · (Edited)
Quick question, maybe a sillyone with an obvious answer;

When i slow to a stop or any time i slow, i down-shift. Are you just putting it in neutral and utilizing only brakes to increase mpg? and also (since you said your commute is downhill 1 way) are you also popping it into neutral and coasting as much as possible? Just curious how you are driving it.
My commute is an out and back - I posted both a description of my commute and the elevation profile earlier in this thread.

I don't coast in neutral unless I'm doing a very slow shift, i.e., I started a shift in anticipation of traffic and guessed wrong, or I when I'm stopping and I would need to downshift past third gear when I was cruzing in 5th or 6th. From cruzing speeds in 4th and lower I'll shift all the way to 2nd before putting the clutch in for the stop. During decelerations to a stop I frequently skip a gear to ensure longer periods of DFCO between shifts. Skipping a gear can put more wear on the clutch so these tend to be longer shifts to give the ECU a chance to stabilize the engine speed followed by a relatively quick clutch release to reduce clutch slippage.

Coasting in neutral with the wheels disengaged from the transmission requires the ECU continue firing the injectors to keep the engine turning. This consumes about 0.2L/hour. Coasting in gear allows the wheel spin to keep the engine turning and the car will actually turn off the injectors. You can feel the injectors turning off and then back on. To see it, put your car in Metric (select the menu button until you get to the options screens - rotate the selector knob until you get a display that will say US/Metric/Imperial. Press the button on the end of the stalk and then rotate the selector knob until Metric is selected. Press the button on the end of the stalk. Now press the menu button until you are back to the normal trip information displays. Rotate until you see your instantaneous speed, range, and fuel economy. Now find a road with a slight downhill (1-2% is all you need) and has a speed limit above 50 MPH and drive down it in 6th gear using Cruze control. Pay attention to two things - your butt dyno and the instant fuel economy. When you see the display drop to 0L/100KM, your car has turned off the injectors. This is Deceleration Fuel Cut-Off (DFCO). Also, if you're paying attention to your butt dyno you will actually feel the car enter DFCO by a tiny, sudden surge/drop in acceleration about two seconds before the display shows 0L/100KM. About one second before the display leaves 0L/100KM you should feel a tiny, sudden surge in power from the car as it turns the injectors back on.

DFCO will be entered anytime you (or the Cruze control) let off the throttle for at lease one second the engine speed is above 1500 RPMs at the end of that second. The car will exit DFCO when you (or the Cruze control) press the throttle, you push in the clutch, or the engine speed drops to 1250 RPM. Gear doesn't matter - the Cruze will even enter DFCO in 1st. Automatics will maintain DFCO across downshifts.

The Cruze can turn the injectors off and then back on in less than a second, which is too short a time span for the display to report, but not too short for the butt dyno to report it. This is why some members have complained both here and to their dealerships that their car surges when descending long shallow grades. The car is repeatedly entering and leaving DFCO. This is normal and the car is operating as designed.

Other members have had success in using coast in neutral for fuel economy, so the choice here is yours. I was taught to drive by a pair of SCCA certified instructors and coasting in neutral was drilled into me as a big no-no. Also, I'm not convinced that coasting in neutral will coast enough further to cover the 0.2L/hour idle fuel use. I suspect in general driving the two methods will return the same real world results.
 

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001.jpg 002.jpg todays update, still looking pretty good.. golfing tomorrow so have a longer drive through some construction areas... at the very least I should be joining the 700 club
 

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Discussion Starter · #52 ·
893 Estimated Range

Trip 8 of 27

Estimated Range Left: 656 miles
Driven: 236.9 miles
Estimated Total Range: 893 miles
Range buffer: 93 miles / 1.9 gallons
MPG: 53.2

Still no movement in the gas needle. I'm going to stop guessing what the estimated range will do or when the gas gauge needle will start to move.

IMG_20130820_162111.jpg IMG_20130820_162046.jpg
 

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Discussion Starter · #53 ·

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Discussion Starter · #54 ·
Trip 9 of 27

Estimated Range Left: 643 miles
Driven: 267.4 miles
Estimated Total Range: 910 miles
Range buffer: 110 miles / 2.2 gallons
MPG: 53.9

Range started to drop right at 248 miles when I made my hard right (40+ MPH to avoid loosing too much momentum) onto C-470 and started accelerating up to the freeway. I saw a range as low as 636 miles this morning. Prior to this point I hadn't seen the range drop below 650 miles. The gas needle did indeed move 18 miles later while decelerating on and descending the exit ramp from the freeway near the end of my drive this morning, but looking at the pictures you can't tell when sitting on level ground. In this regard the Cruze is like all the other GMs I've driven and show lower fuel levels when pointed downhill. I hadn't noticed this before. The daily fluctuations in the average MPG are starting to even out as well.
 

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Good job Mike.

Sent From An Antique,
My Original Droid.
 

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Discussion Starter · #56 ·
Trip 10 of 27

Estimated Range Left: 599 miles
Driven: 296.4 miles
Estimated Total Range: 895 miles
Range buffer: 95 miles / 1.9 gallons
MPG: 53.4

The gas gauge needle is still above the "full line" but it is definitely moving now. The DIC reports that I have used 5.6 gallons. This gives me an estimated 10.5 gallons left in the tank. Remember, I filled to the top of the fill pipe before I started. Each day 800 miles is looking more and more achievable. In fact it's starting to appear that I'll be able to fill up at the end of this at my normal gas station which would put the tank around 840 miles.

IMG_20130821_161807.jpg IMG_20130821_161819.jpg
 

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Discussion Starter · #58 ·
Trip 11 of 27

Estimated Range Left: 575 miles
Driven: 326.9 miles
Estimated Total Range: 902 miles
Range buffer: 102 miles / 2.0 gallons
MPG: 54.0

So 900 is definitely out of the question unless I can quickly figure out how to get my roundtrip to 55 MPG or higher. I think I can get 830 miles and have just the low fuel warning light on but have the car still displaying range. The next round trip is iffy - 888 miles.

As a slight humorous thought - gas prices went down at my normal station yesterday. Normally with 300 miles on my tank I would have stopped since I know they tend to jump up on Thursdays. If I had stopped first click would have been less than a gallon based on where my gas gauge was pointing.

It appears the gas gauge in the ECO MT is calibrated to show "Full" at 10.5 to 11 gallons. Anyone who thinks their tank is full and the needle is below the center of the "Full" line has at most 10 gallons in their tank.
 

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Discussion Starter · #59 ·
I passed another Cruze ECO this morning and I was hypermiling. I don't know if it was a gas or diesel burner though.
 
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