31 MPG is this for real? 2017 6.2 Denali

Bikemobile · August 26, 2017

Gm Oil Life Monitor

amxguy1970 · August 26, 2017

The best I ever got was 30.2 MPG with cruise control set at 62 mph on flat road. The truck was on V4 mode for the most part of the drive.

But but V4 is useless and doesn't save anymore gas than V8 mode and is much less reliable and eats oil and fails half the time, that cannot be true that it helped get that mpg...

Tyler

wildlyfe200 · August 26, 2017

But but V4 is useless and doesn't save anymore gas than V8 mode and is much less reliable and eats oil and fails half the time, that cannot be true that it helped get that mpg...

Tyler

As much a you may have a bias against V4 mode is does make a difference. I would have had it disabled in my tune if it didn't. Just watch the instant MPG when you are in V8 and V4.

I also have not experienced any failures with V4 mode and/or oil consumption problems.

I can still understand why people would want it disabled.

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Nanotech Environmental · August 26, 2017

But but V4 is useless and doesn't save anymore gas than V8 mode and is much less reliable and eats oil and fails half the time, that cannot be true that it helped get that mpg...

Tyler

Except that it actually does save fuel over V8 mode. It's not even debateable & is provable mathematically, scientifically and from an engineering standpoint as well. Although the early ones had some well known issues, like waaaay back in the 07-11 period, those have pretty much all been addressed for the most part. There just doesn't seem to be near as much chatter about it now as there was 5-8 years ago.

My '17 spends quite a bit of time in V4 and doesn't appear to be using any oil (almost 15,000km on it so far). Time will tell if it decides to fail at some point. However, there seems to be quite a few with 80-100k miles on the 14-up models with few or no issues.

newdude · August 26, 2017

Your DIC is showing MPG for the last 25 miles. So, in 25 miles of whatever driving you were doing, you averaged 31mpg. The more realistic calculation would be your trip A or trip B MPG, or the 450mi setting for the MPG screen you are on.

wildlyfe200 · August 26, 2017

Your DIC is showing MPG for the last 25 miles. So, in 25 miles of whatever driving you were doing, you averaged 31mpg. The more realistic calculation would be your trip A or trip B MPG, or the 450mi setting for the MPG screen you are on.

I totally understand I was only doing 25miles of a straight run as soon as I had to stop or slow down it would have dropped down.

It is still amazing that this truck can do that. I'm sure I could do 25mpg for a long trip driving 55-60mph. Normally I drive 80-85 so I guess it is a little unrealistic for me.

For 450 miles I think i was around 16.2mpg but I do a lot of driving at work moving my tools from place to place. I'm in out of my truck all day until I go home.

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NWI Denali · August 26, 2017

It's the last 25 miles. Totally possible. I bet the last 50 miles is like 24-25 and the last 400 miles to be about 19-21

2014 Silverado Z71

^this

gmissed · August 28, 2017

My best ...25 MPG over 250 miles, hand calculated. Average speed probably in the 65-70 MPH area. 6.2 liter engine.

Ridersfan · August 28, 2017

Shutting your a/c off will even move the bar a little, so I do think that the trucks read accurately when that tracking is recorded

Sierra 5.3 · August 28, 2017

But but V4 is useless and doesn't save anymore gas than V8 mode and is much less reliable and eats oil and fails half the time, that cannot be true that it helped get that mpg...

Tyler

As much a you may have a bias against V4 mode is does make a difference. I would have had it disabled in my tune if it didn't. Just watch the instant MPG when you are in V8 and V4.

I also have not experienced any failures with V4 mode and/or oil consumption problems.

I can still understand why people would want it disabled.

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Except that it actually does save fuel over V8 mode. It's not even debateable & is provable mathematically, scientifically and from an engineering standpoint as well. Although the early ones had some well known issues, like waaaay back in the 07-11 period, those have pretty much all been addressed for the most part. There just doesn't seem to be near as much chatter about it now as there was 5-8 years ago.

My '17 spends quite a bit of time in V4 and doesn't appear to be using any oil (almost 15,000km on it so far). Time will tell if it decides to fail at some point. However, there seems to be quite a few with 80-100k miles on the 14-up models with few or no issues.

I think you guys missed the sarcasm. It seems like he was just stating what others have argued and beat to death, but have no proof of. Or I just missed the seriousness... #AnotherDayAnotherBeer

Nanotech Environmental · August 28, 2017

I think you guys missed the sarcasm. It seems like he was just stating what others have argued and beat to death, but have no proof of. Or I just missed the seriousness... #AnotherDayAnotherBeer

Sarcasm usually isn't obvious in posts, unless the person marks the end of their post with a /sarc or /s......

wildlyfe200 · August 28, 2017

Didn't seem sarcastic to me. I think I fed troll.

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Marv88 · August 28, 2017

I did not buy my truck (2016 5.3L regular cab) for economy however my less than 11 mpg average during non aggressive city driving with lots of stop n go (most of my driving) seems a bit low as does the best of less than 22 mpg on an all highway trip at an average speed of about 65 mph with no load. The service advisor said ithis is normal for "real" mileage but I wonder now after seeing the much better mileage some of you are getting in the larger trucks with larger engines.(?).

redwngr · August 28, 2017

I track every fill on this 5.3L, and have hand checked enough that I know it is close.

The best 25 miles on this truck is 36.x, and yes it was a one time thing, driving out of the mountains (southbound from Yosemite) on 2 lane.

It is common to seen the 'last 25' reach 24-25 mpg.

Fill-ups are normally at or near the fuel light warning being on and are usually 20 - 21, with the 20's installed (slightly less with 18" KO2's).

I don't think it's ever had a complete tank go 24 - 25.

Towing 7 x 14 x tall enough it won't go in my garage from Detroit to Phoenix (and later return) on the interstate at posted (or +5), it was always less than 10 mpg.

I can believe the 30+ for 25 miles mileage posted by the OP, but certainly wouldn't expect it to repeat or be a common occurence.

wildlyfe200 · August 29, 2017

I did not buy my truck (2016 5.3L regular cab) for economy however my less than 11 mpg average during non aggressive city driving with lots of stop n go (most of my driving) seems a bit low as does the best of less than 22 mpg on an all highway trip at an average speed of about 65 mph with no load. The service advisor said ithis is normal for "real" mileage but I wonder now after seeing the much better mileage some of you are getting in the larger trucks with larger engines.(?).

That seems a little low for city driving but I do not do all city driving and have not burnt a tank in the city so mabey someone else can chime in. But 22mpg for highway is spot on. Normally I get 18-19mpg driving 80-85. I was really trying to get 31mpg and it was only for a 25mi straight run. My 400mile average is about 16.5mpg. I drive aggressive at times.

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