Hypermiling - I'm Getting 28.8 MPG

Bobv07662 · June 4, 2019

Real world report on a 500 mile round trip last week...no hypermileing here!

Southbound I81 Jersey to Roanoke Va, 80mph got me 22.1 mpg, coming back north 2 days later at 75mph mileage went up to 23.2.

RST 2wd 5.3 8speed, no complaints here.

Wiggums · June 4, 2019

That clearly shows how unreliable EPA numbers are. Sometimes it's spot on, but not always. My Benz barely got EPA's 26 mpg highway while my Silverado easily exceeds it.. 20 mpg highway and I'm getting 26. I'm impressed with the Silverado.

Stex · June 4, 2019

I am amazed at the number of folks that do not realize the dash computation is not that accurate. One needs to fill up at the same pump and run a tank or half and calculate it manually. Camaro forums have been all over this. One can also never reset the overall MPG and run say a year and get a better idea of MPG.

Wiggums · June 4, 2019

9 minutes ago, Stex said:

I am amazed at the number of folks that do not realize the dash computation is not that accurate. One needs to fill up at the same pump and run a tank or half and calculate it manually. Camaro forums have been all over this. One can also never reset the overall MPG and run say a year and get a better idea of MPG.

I'd agree with you if I was still driving the 2012 Ford F-150. Ford's trip computer was every 10,000 miles so I'd reset it every 10k miles. All three times, it was over 23 mpg, usually 23.7 or 23.8, and I can confirm it was overly optimistic by 2 mpg, sometimes 3 mpg. So I got 21 mpg with about 30% city and 70% highway. EPA said it'd get 19 mpg highway so i did better.

It is much more spot on with Chevrolet, the past three times I measured it, it was off by 0.2 or 0.3 mpg either way. And others have chimed in, the 2019 and afterwards, the trip computer is much more accurate.

aseibel · June 4, 2019

30 minutes ago, Stex said:

I am amazed at the number of folks that do not realize the dash computation is not that accurate.

14 minutes ago, Wiggums said:

It is much more spot on with Chevrolet, the past three times I measured it, it was off by 0.2 or 0.3 mpg either way. And others have chimed in, the 2019 and afterwards, the trip computer is much more accurate.

I've been doing hand calcs on most tanks with my 2015 and its nearly always within .25 mpg of the DIC. (granted, the DIC is always higher)

I've also seen others report that the new '19's are spot on.

Wiggums · June 4, 2019

9 minutes ago, aseibel said:

I've been doing hand calcs on most tanks with my 2015 and its nearly always within .25 mpg of the DIC. (granted, the DIC is always higher)

Only 0.25 mpg? Way better than my Ford's trip computer.

My 2012 Ford did 850 miles once on a single tank, all highway, and the trip computer reported 27.5 mpg after all kinds of hypermiling techniques. I got excited until I got to the pumps.. it was off by 3 mpg so I actually got 24.5. Still better than EPA's 19 mpg highway.

So the 28.8 mpg I got with the Silverado.. it could either be 28.5 or 30.1 mpg (I haven't driven much). That's still damn good! Today, I'll be filling it up with the same gas tank and at the same pump today, will find out how much I'm off. The past three times, I didn't use the same pump.

aseibel · June 4, 2019

17 minutes ago, Wiggums said:

Only 0.25 mpg? Way better than my Ford's trip computer.

My 2012 Ford did 850 miles once on a single tank, all highway, and the trip computer reported 27.5 mpg after all kinds of hypermiling techniques. I got excited until I got to the pumps.. it was off by 3 mpg so I actually got 24.5. Still better than EPA's 19 mpg highway.

So the 28.8 mpg I got with the Silverado.. it could either be 28.5 or 30.1 mpg (I haven't driven much). That's still damn good! Today, I'll be filling it up with the same gas tank and at the same pump today, will find out how much I'm off. The past three times, I didn't use the same pump.

I just drove over 1000 miles down to Iowa and back and I was very close to 20 mpg on each of 3 tanks. (Both DIC and hand checked) I was cruising around 72 mph for most of it. 3.42 gears.

My truck has an EPA rating of 22 highway. I believe the EPA test to determine highway mpg is done at below 60 mph. So it makes sense that they would get 2 mpg more at a slower speed.

Anyway, it is known that the truck is not exact with its calculations. I wonder how much coasting throws it off. If you spend more time coasting that the average driver, the DIC often reads 99 mpg during that part, but that isn't technically accurate. No one seems to know the algorithm that the computer uses, whether its a sum of all the instantaneous readings, or what. But doing the math yourself is more exact for your driving- miles driven/ gallons burned. But that also includes any amount of fuel you waste cold starting, idling, remote starting, or otherwise sitting in traffic. So even though your engine is running, if you are not moving, that fuel doesn't contribute to your moving fuel efficiency. The calculation is more representative for your cost of ownership per mile than actual fuel efficiency of the vehicle. The longer your average trip, the more accurate the number should be due to less idling and cold starts.

Edited June 4, 2019 by aseibel

Wiggums · June 4, 2019

22 minutes ago, aseibel said:

I just drove over 1000 miles down to Iowa and back and I was very close to 20 mpg on each of 3 tanks. (Both DIC and hand checked) I was cruising around 72 mph for most of it. 3.42 gears.

My truck has an EPA rating of 22 highway. I believe the EPA test to determine highway mpg is done at below 60 mph. So it makes sense that they would get 2 mpg more at a slower speed.

Anyway, it is known that the truck is not exact with its calculations. I wonder how much coasting throws it off. If you spend more time coasting that the average driver, the DIC often reads 99 mpg during that part, but that isn't technically accurate. No one seems to know the algorithm that the computer uses, whether its a sum of all the instantaneous readings, or what. But doing the math yourself is more exact for your driving- miles driven/ gallons burned. But that also includes any amount of fuel you waste cold starting, idling, remote starting, or otherwise sitting in traffic. So even though your engine is running, if you are not moving, that fuel doesn't contribute to your moving fuel efficiency. The calculation is more representative for your cost of ownership per mile than actual fuel efficiency of the vehicle. The longer your average trip, the more accurate the number should be due to less idling and cold starts.

I have 3.23 on mine and I believe the 2019 V8 is more efficient with the DFM. I don't use the cruise control, I maintain a steady foot on the gas pedal so that the DFM doesn't keep turning on and off. I never use the cruise control, I just wish there was a 30-mph leeway with the cruise control, ranging from 50 to 80 mph, depending on terrain. I hate braking while going downhill and I hate flooring the gas while going uphill. I'm OK with 50 mph to 80 mph, it doesn't have to be exactly 65 mph.

EPA highway gas mileage on mine is 20, I believe, it's a 4x4. I think EPA's testing method includes a full throttle a few times even at highway speeds to stimulate merging into traffic. I don't do that.

Some cars are immune to my hypermiling techniques. I could barely hit the 26 mpg my Benz C300's EPA numbers showed, even going 60 mph for a couple hours. It sucked! My Isuzu Trooper said 19, I was lucky to get 13 mpg! No DIC in the Trooper, all hand-checked.

My 2012 Ford F-150 responded very well to my hypermiling techniques, usually got 3 to 4 mpg better at 21 mpg, but the 2016 F-150 was pretty much in line with EPA numbers, I was lucky to get 18 mpg in a mix while EPA numbers showed 15/19. Both were Supercrew 4x4 XLT's with 5.0 V8.

EPA no longer does the flawed technique which resulted in Prius getting way overly optimistic numbers. I don't know what part was changed though.

I have my car in metric so it measures how many litres for every 100 kilometers. When I'm coasting, I do see zero which would be accurate. Zero litres consumed per 100 kilometres. I don't know why it would not show above 99 mpg which is obviously not accurate.

Philipgonzales3 · June 5, 2019

On 5/31/2019 at 12:00 PM, Wiggums said:

I have to justify the purchase of the Silverado to my girlfriend, boss, and my parents who lecture me whenever they think a purchase is frivolous.

The most common criticism I got for buying a Silverado was the gas mileage so I am now demonstrating to them I am getting the same gas mileage as I did on my 2008 Benz C300, a very tiny cramped sedan with a shitty V-6 and a lousy 228 ponies. Now, I have a big ass V8 with 355 hp, 4x4, and way more space in the back, with the same gas mileage I did on my Benz... so now I can say, "See?"

I've gotten 25mpg on the highway at 65mph. I was impressed. I've always heard about how expensive trucks are as far as far cosumption and blah blah blah. I only drive about 9K a year. About 20 miles a day to work and back but I telework once a week and I'm off once every other week. The rest of the 9k is because we use my vehicle for any trips big or small (mostly small) as my fiancee does not like to drive.

Anyway long story short I went to the Edmunds site and they have a fuel cost calculator based on your vehicle and gas prices in your zip code. My old car was a 2016 focus ST. Little bitty 2.0 Liter (turbo though). It cost me a whopping $2.00 more a week in gas to get to work and back. Basically it's like a 2$ difference per 100 miles. The focus did take premium but I was always on the throttle in that car so I'm sure I was not getting epa estimated mpg's lol.

I'm like man this V8 is a gas sipper! The difference in mpg's is negligible at best in my opinion. And I'm glad.

Wiggums · June 5, 2019

I couldn't be any happier with the fuel economy of my Silverado! I know it will also hold its value very well so I'm going to sleep better at nights.

Bobv07662 · June 6, 2019

My real world mile figures I reported above were from the DIC, the actual measured and calculated mileage was .2 mpg better. The 2019 DIC is very accurate!

Wiggums · June 6, 2019

Just got back and I'm happy to confirm my DIC was spot on. 24.7 and I measured it too. Very very very happy with the mileage I'm getting right now. Excellent resale, gas mileage, spacious interior, cannot complain here!