Question about 2016 6.2L GMC

Icecreman · May 31, 2016

Has anyone done any MPG calculations using premium vs. regular in the 6.2? I was thinking about this today as I filled my 6.2 for the first time. I got plus thinking it was 91 octane only to see is was 89 after the guy started filling it (I've been driving a diesel for the last 10 years so I forgot plus was 89, and we don't pump our gas in Jersey so I didn't see the number).

I'd be interested to see some actual mileage results although I'll probably just run premium.

bdbake01 · May 31, 2016

This will be a HIGHLY contested topic, but I have repeatedly, tank after tank, on the EXACT same commute, lost 3+ mpg going from 91/92 to 87.

GMC-AT · May 31, 2016

I believe it... but again, assuming you can afford to drive a 50K truck to begin with - the cost of premium fuel should be easy.

Binobanbino · May 31, 2016

I've been using premium fuel in the 6.2 since I got it. GM recommends using premium I will continue using premium.

dreisenauer · June 1, 2016

I went from an 04 sierra to a 6.2 with 3.23 gears. It's an awesome upgrade. The 04 was decent but the new one handles a 7000 lb trailer like the old one handled 3500 lbs. And the 6.2 gets ~30% better mileage towing so far. I've always run premium to date.

CadillacLuke24 · June 1, 2016

The 6.2 should run ok, on 87, but I'd almost bet money that premium will return better fuel economy. I've waged the same debate wtih my dad regarding my Cadillac (with the Northstar). I've seen 2-3 mpg increase when running premium (which is what it was tuned for).

Albytruck · June 1, 2016

Let's get to the real question.... you are buying a 50K truck and you are worried about a few bucks extra in fuel cost? Run the premium gas - it what GM recommends, plus you take full potential of the beast. IF you are worried about nickels and dimes..get an S-10 with a 4.3

Did I say was going to run 87? Uh, no. What did I say I was "worried" about? Ummm, nothing in my post.

Take your 4.3 comment and shove it GMC-AT. No need for sarcasm around here.

Looking for info on the 6.2 as there are not many in my area. One of the dealers I called and talked to that had one in stock couldn't answer my question about the rear end gear ratio.

Once again it was a question, does my post say anything about being worried?

Thank you to those who have given mature responses and actually answered my questions.

TJay74 · June 1, 2016

OP, TJay is incorrect, you do not HAVE to run premium and it will not damage the engine if you don't. It will just reduce the power and mpg some though, there is a difference between Required and Recommended and some people don't quite understand that.

Good luck, my 5.3 runs good and am very happy with it, it has plenty of power. If I was towing close to the limit I would consider a 6.2 but I am not a fan of 20's and leather and all that stuff. Maybe one day they will allow the 6.2 to trickle down the model range like everyone has been asking, until the 5.3 is great. I should go try to find some E85 and see how that changes it.

Tyler

Sorry, seems you are incorrect here. Manual states in black and white letters that anyone who went thru the 6th grade can read and understand. States to use 91 octane or higher and that if 87 octane is used that audible knocking can be heard which can damage the engine. I bought my 2016 on 3/8/16, dealer didn't listen to me and put 87 in mine, you could hear the engine pinging as I was going over an overpass as the sound reflected off of the retaining walls. My HP Tuners logs also show the ECM is picking up knock on 87 and 89, when it get hot enough it will even get some knock while on 91.

So with that, do as you want. If you want to go around trying to convince owners of 6.2 that they can run 87 then more power to you, just makes you an internet troll in my eyes. There are too many of us in here that have done the research with the correct tools and know better to run anything less than 91 octane all the time in the 6.2 trucks. Heck the 5.3 trucks shouldn't even run anything less than 89 to be honest.

redwngr · June 2, 2016

New here,

I have an 04 Silverado Z71 Crew Cab. I am looking at 2016 Sierra Crews.

I like the 5.3 but I am really interested in the 6.2L .

The question is does the 6.2 require Premium fuel? I have not actually driven one yet.

Also when I look on the dealer web page and also open up the window sticker it does not mention what the rear end gear ratio is on the 6.2's,

Thanks in advance

How do you 6.2 owners like the engine and 8 speed tranny

Albytruck

6.2 standard is 3.23's

6.2 with NHT, gets 3.42's

1300c · June 2, 2016

6.2 standard is 3.23's

6.2 with NHT, gets 3.42's

^This and definitely run premium gas.

After driving 6.2 trucks with both rear ends we ordered one with the max tow package. It's worth the extra money to me to get the higher tow rating (11,800 vs 9200lb), and extra cooling capacity. Also the bigger mirrors which allow a lot better visibility along with the back up lights that are great.

Albytruck · June 3, 2016

Thanks for all of the information it is greatly appreciated.

Srode1 · June 3, 2016

The 6.2 should run ok, on 87, but I'd almost bet money that premium will return better fuel economy. I've waged the same debate wtih my dad regarding my Cadillac (with the Northstar). I've seen 2-3 mpg increase when running premium (which is what it was tuned for).

Well I just did a test on the better gas mileage on a 740 mile trip. First tank (409 miles) mostly 75mph except construction zones where the speed limit dropped to 45 or 55, there were a few, and driving through big city with lower speed limit, and one 10mile trip to a residential area to visit someone on the way briefly - with 87 octane I got 21mpg on the trip computer, hand calculated 20.45mpg. Fairly flat terrain, no wind to speak of.

2nd leg (334 miles) was again 75mph on 93 octane which about an hour into the drive started getting a quartering tailwind, some construction but little. One big city with reduced speed limit, then the last couple hours turned to full tail wind, not quartering - don't know the wind speed was just looking at the occasional flag direction, but I would guess 5-10mph. Headed into a town at the end, through a bit of city residential traffic to fill up. The trip computer said 21.4mpg, hand calculated 20.86mpg.

Price difference in fuel in this case was 10% more. Fuel economy difference - 2%

Of course a test like this with N = 1 on each tank and not exactly the same conditions has a pretty large margin for error, but in general, there doesn't seem to be any reason to think the higher grade fuel will make any real difference in fuel economy on the highway with a 6.2, when running empty. Pulling a load or around town, that might show more of a difference. If the engine was knocking on the 87 octane the ECM should have detuned the engine and the fuel economy difference should have been more noticeable in my opinion.

CadillacLuke24 · June 4, 2016

Well I just did a test on the better gas mileage on a 740 mile trip. First tank (409 miles) mostly 75mph except construction zones where the speed limit dropped to 45 or 55, there were a few, and driving through big city with lower speed limit, and one 10mile trip to a residential area to visit someone on the way briefly - with 87 octane I got 21mpg on the trip computer, hand calculated 20.45mpg. Fairly flat terrain, no wind to speak of.

2nd leg (334 miles) was again 75mph on 93 octane which about an hour into the drive started getting a quartering tailwind, some construction but little. One big city with reduced speed limit, then the last couple hours turned to full tail wind, not quartering - don't know the wind speed was just looking at the occasional flag direction, but I would guess 5-10mph. Headed into a town at the end, through a bit of city residential traffic to fill up. The trip computer said 21.4mpg, hand calculated 20.86mpg.

Price difference in fuel in this case was 10% more. Fuel economy difference - 2%

Of course a test like this with N = 1 on each tank and not exactly the same conditions has a pretty large margin for error, but in general, there doesn't seem to be any reason to think the higher grade fuel will make any real difference in fuel economy on the highway with a 6.2, when running empty. Pulling a load or around town, that might show more of a difference. If the engine was knocking on the 87 octane the ECM should have detuned the engine and the fuel economy difference should have been more noticeable in my opinion.

Hmmm maybe not as noticeable as I would have thought. Granted, a DeVille and a Silverado are two entirely different beasts, but still.

At least in my DeVille, over the same 250 mile route, with fairly similar weather conditions each time, Regular (85 around here) would return 25 mpg consistently. Premium would return 27 mpg.

Perhaps the 85 octane would be explanation. I dunno.

At any rate, I'm running premium. I love that launch pedal

fedmogul89 · June 4, 2016

I'm actually really curious to see if any previous Ram owners from who owned a 2014-2016 model like the 6.2 8 speed over the 5.7 8 speed. I have the 5.3 6 speed, so I cant attest. But i owned a 2015 Ram 1500 and I really loved the 8 speed. Thought it functioned pretty fluidly and didn't shift hard at all. Does the 6.2's 8 speed have the "adaptable" function where it adjusts to your driving and the gear shifts over time?

Dnt · July 1, 2016

I just traded my 2014 5.3 6spd last friday and this 2016 Denali with the 6.2 8spd drives like a totally different truck. The 8 spd is buttery smooth when compared to the clunky "does not know when to shift" 6spd. This truck puts a big smile on my face every morning when I turn the key. On the first 700 miles it is averaging 21 mpg and that is with 100 miles of dealer test drive miles before I got it and I have pulled a 2000 lb trailer for over 100 miles of that 700. I suspect it will be in the 23 24 mpg range on long trips or maybe better! I think everyone has heard about the GM lawsuit payments for overstating mileage on their vehicles? I believe that GM may currently be "understating" mileage............................. Kudos to GM they have done one heck of a job on this 6.2 8spd with 3.23 gearing and I do not mean to be so exuberant but dangit this Denali interior is friggin awesome LOL.