2014+ Gas Mileage (MPG) Topic

[gmc_downstream]

I don't know if it's been said in here but with regular gas I was getting roughly 14 mpg don't know the exact number. Then I put premium in and it bumped up to 16.1. I was very surprised

[Dnt]

Premium OH MY GOSH that costs extra cash!!!!!!!!!!!!!! LOL I thought about it but right now I have been running a few tanks of nonethanol 87 octane. Now this last tank I filled up with 10% ethanol 87 octane. Next 3 to 4 tanks will be E85 I did not want to shock the trucks system with all that alcohol and get it drunked up so I am running a tank of 10% before I blast it with the E85. Might try some Premium fuel at some point but I am hoping that these new engine controllers can tune the engine to burn the E85 just as efficiently as the nonethanol fuel. In the past they have not been able to get nearly as good of gas mileage on the E85 it just sounds counter intuitive to me that the E85 produces more Horsepower but burns less efficiently but I never got goods grades is science in school so I guess I just do not have the needed mental capacity to understand that. Several trucks on the Fuelly site now so if they actually keep their data entered correctly we should be seeing real world results pretty soon.

Edited March 9, 2014 by MyFavTruck

[Ton J]

Something of interest:

I record the gallons used, the odometer reading, and the trip computer’s mpg report. Given the vagaries of filling a gas tank to exactly the same level at each fill-up, some variability is understandable.

 

Mark Allen, GM’s director of global energy, mass, and aerodynamics, says some inaccuracy is unavoidable. “The density of fuel varies. We have no way to measure it. Mobil might be different than Shell. Summer gas to winter gas could be a big difference.” And then there are vapor-recovery systems. With modern cars’ sealed fuel tanks, gasoline vapor accumulated in the tank is absorbed by a charcoal-filled canister. Periodically, this canister is purged by the engine. “If the weather is hot, you generate lots of purge,” says Allen. “This unmetered fuel isn’t counted by the trip computer.”

[Jon A]

 

 

First highway trip with the Denali 6.2:

 

 

I have 34" tires and have not corrected the computer. Adjusting for the 7.4% error the actual numbers are 17.3 MPG at a 68 MPH average.

 

This was a round trip from the Seattle area to the top of Snoqualmie Pass (3000 ft elevation) and back again. The engine is still new (fewer than 300 total miles).

 

I'm pretty happy with that. It's rated at 20 for the highway, I've taken off the front airdam, lifted it 2" front, 1" rear, and put much bigger and heavier 34" tires on it.

 

 

 

 

I repeated the same trip above. The truck now has about 1500 miles on it so it's a bit more broken in. I have also corrected the speedo for the tire size and I've disabled AFM completely.

 

 

 

 

 

 

So without the AFM it got 18.1 on the same trip. I calculated by hand as well and it was within .05 MPG (although doing that for such short trips is not very accurate). The engine is a bit more broken in, but I'd say most of the gain was from the simple fact there was less traffic this time.

 

The 400 mile average has several weeks of city driving and since I only live 3 miles from work I only get about 11 MPG on that daily commute.

[strike1st]

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

[Ton J]

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

Any deep North boys noticing this?The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

Any deep North boys noticing this?

 

I almost agree with that statement but its doest get that cold here to much and ive had this problem since the first update which first week of Jan and weather here was pretty good. But I did find emission test from California that General Motors did on the truck and should after 4000 miles and 10 road test 2wd 5.3L 2014 Silverado 12.4mpg in the city on reg. And 17mpg on hwy. Am going upload the page later. And it shows the EPA at 16mpg in city 22mpg hwy but no testing info.

Edited March 10, 2014 by Ton J

[strike1st]

I almost agree with that statement but its doest get that cold here to much and ive had this problem since the first update which first week of Jan and weather here was pretty good. But I did find emission test from California that General Motors did on the truck and should after 4000 miles and 10 road test 2wd 5.3L 2014 Silverado 12.4mpg in the city on reg. And 17mpg on hwy. Am going upload the page later. And it shows the EPA at 16mpg in city 22mpg hwy but no testing info.

 

What are those other test fuel types? I don't touch E85.

[Ton J]

 

What are those other test fuel types? I don't touch E85.

All the test GM did on the Silverado an other trucks before release on the market. as you can see the results of the test. real world. here is the list trucks they by model. based California Emission test but it shouldn't matter because they have the toughest laws on this stuff

[Ton J]

I almost agree with that statement but its doest get that cold here to much and ive had this problem since the first update which first week of Jan and weather here was pretty good. But I did find emission test from California that General Motors did on the truck and should after 4000 miles and 10 road test 2wd 5.3L 2014 Silverado 12.4mpg in the city on reg. And 17mpg on hwy. Am going upload the page later. And it shows the EPA at 16mpg in city 22mpg hwy but no testing info.

 

 

What are those other test fuel types? I don't touch E85.

Top 2 are E85

3 one is unleaded

bottom one are EPA standard that you see on the window.

[Ton J]

 

Top 2 are E85

3 one is unleaded

bottom one are EPA standard that you see on the window.

Little more info

[Ton J]

dealer called afm system was effected by updated and they said instead of using less Gas it's using more. And GM tech heads can't figure it out. Update did something to system.

[iCryWheniGoPoop]

I wish you were closer so I could get a copy of your calibration, then I could see how much different it is from mine. My MPG is everything that GM claims if I'm actually driving like an adult. It's hard to keep my foot out of it though since I started tuning.

 

It's good to hear that they are working on your issue, I hope you get it resolved in a timely manner. I would hate to see you down at the ford dealership because GM is dragging there feet.

Edited March 10, 2014 by iCryWheniGoPoop

[Ton J]

I wish you were closer so I could get a copy of your calibration, then I could see how much different it is from mine. My MPG is everything that GM claims if I'm actually driving like an adult. It's hard to keep my foot out of it though since I started tuning.

 

It's good to hear that they are working on your issue, I hope you get it resolved in a timely manner. I would hate to see you down at the ford dealership because GM is dragging there feet.

You crazy as hell, Ill never buy a Ford. Ill stay with Chevy problems and all I just want it fixed. It was just fine when I first got it. Chevy to end man.

[Bikewhisperer]

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

 

Exactly the same here. The other morning it was -12c or so, warmer than what weve been experiencing lately but same fuel economy as usual. It kept warming up to -5c and on my way home I beat my pathetic 50km record set on my second tank of fuel ever. Nice and warm today, just above melting, and I am probably using 25-30% less fuel than I ever have.

 

WFT is up with that? It's like a switch was flipped at -5c.

[strike1st]

 

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

 

Exactly the same here. The other morning it was -12c or so, warmer than what weve been experiencing lately but same fuel economy as usual. It kept warming up to -5c and on my way home I beat my pathetic 50km record set on my second tank of fuel ever. Nice and warm today, just above melting, and I am probably using 25-30% less fuel than I ever have.

 

WFT is up with that? It's like a switch was flipped at -5c.

 

EXACTLY! GM needs someone looking at this...even though the southern boys in this thread think we're nuts...this is a real issue in the cold!

 

Where is the GM service Rep? They seem to show up in every other cotton picking thread on this site?!