Question about break-in

Boardmember · February 15, 2018

I have ~2700 miles on my odo and manually calculate mpg on every tankful. I’ve changed oil once already and only use Top Tier fuel (usually 87 octane but a couple times I’ve back-to-backed 89 just for kicks)

Im getting about 15mpg, on exclusive highway, about 17. My prior trucks - one with 8sp, one with 6sp - did a lot better than this but had more miles.

What experiences have y’all had with mpg related to break-in periods?

Grumpy Bear · February 15, 2018

My personal experience is that the running average will continue to climb for about 40,000 miles before it levels off. I've keep track of every gallon and mile on every new car/truck/bike I've owned for that last 40 years and it's a pattern that repeats. Your results may vary. (disclaimer of course)

Paintor · February 15, 2018

You are in Mississippi and there was a EPA waiver to use winter blend fuel....less mpg....since august of last year.

When they start selling summer blend fuel in mississippi again you will see a slight increase.

https://www.washingtonpost.com/news/post-nation/wp/2017/08/30/epa-extends-a-waiver-on-motor-fuel-contents-to-apply-nationwide-not-just-to-texas/?utm_term=.09374a9001e3

Boardmember · February 15, 2018

Facinating. I’ve been aware of winter:summer blends, but never known there to be a difference in this state. So therefore, I’m again ignorant...

does ES the winter mix mean 15% ethanol? The pumps remain strictly labeled “up to 10%”.

Is the ethanol the only difference?

Boardmember · February 15, 2018

Grumpy - I had 23 or 27k on my ‘16 and marveled at the efficiency. In October, we bought a house in town and cut my daily commute from 50 to 16 miles. Hopefully it’ll take some time to get to 23-27-40k. Even with youngest kid in college 4 hours away.

I am literally astounded by the potential that this state switches blends. I read the link Paintor attached. Can someone tell me more?

StuartH · February 15, 2018

49 minutes ago, Boardmember said:

Grumpy - I had 23 or 27k on my ‘16 and marveled at the efficiency. In October, we bought a house in town and cut my daily commute from 50 to 16 miles. Hopefully it’ll take some time to get to 23-27-40k. Even with youngest kid in college 4 hours away.

I am literally astounded by the potential that this state switches blends. I read the link Paintor attached. Can someone tell me more?

More info on the blend, there are many different blends across the country. https://blog.caranddriver.com/the-vapor-rub-summer-versus-winter-gasoline-explained/

Grumpy Bear · February 15, 2018

1 hour ago, Boardmember said:

Grumpy - I had 23 or 27k on my ‘16 and marveled at the efficiency. In October, we bought a house in town and cut my daily commute from 50 to 16 miles. Hopefully it’ll take some time to get to 23-27-40k. Even with youngest kid in college 4 hours away.

I am literally astounded by the potential that this state switches blends. I read the link Paintor attached. Can someone tell me more?

The change in summer, winter is actually done four times a year and is a vapor pressure related adjustment for emission's. BTU per pound fuel delta is small. Smaller than the clamor would wish one to believe. It's a tweak in LPG content whose purpose is two fold. Reduce evaporative emissions and adjust for cold start/vapor lock. Yes there are still carbureted motors in North America.

Ripley's Believe it or Not.

Nanotech Environmental · February 15, 2018

14 hours ago, Boardmember said:

I have ~2700 miles on my odo and manually calculate mpg on every tankful. I’ve changed oil once already and only use Top Tier fuel (usually 87 octane but a couple times I’ve back-to-backed 89 just for kicks)

Im getting about 15mpg, on exclusive highway, about 17. My prior trucks - one with 8sp, one with 6sp - did a lot better than this but had more miles.

What experiences have y’all had with mpg related to break-in periods?

Your fuel mileage seems fairly low. Should be low to mid 20's on the highway. What gears are in it? Do you have an exceptionally heavy foot?

The vehicle is already broke in, so nothing will improve further from that standpoint. Personally, I was hitting some of my best mileage in the first few thousand km on my '17 Sierra 5.3 6sp 4x4 DC. My current long term average (over 20,000+miles), including all types of driving; city highway, stop and go, winter, summer, pulling a trailer, etc., is about 19.5 mpg US.

Boardmember · February 16, 2018

So I take it to my local (and close), friendly dealership service department.

What do do I expect them to look for?

Colossus · February 16, 2018

they'll just check the fuel trim readings and injectors and make sure nothing is out of tolerance using the Tech II scan tool.

grizz_wi · February 16, 2018

Sounds like my MPG's, Im hoping its just the winter gas cause this is terrible. My trip on 2/11 was all highway going 65 and 55, DIC said my averago was 19.2

My lifetime average since owning this truck is 14.4, currently have 4500 miles.

Hell my average with my ole 94 is 13.3 and that has a 5.7

Cowpie · February 16, 2018

On 2/14/2018 at 8:44 PM, Boardmember said:

Facinating. I’ve been aware of winter:summer blends, but never known there to be a difference in this state. So therefore, I’m again ignorant...

does ES the winter mix mean 15% ethanol? The pumps remain strictly labeled “up to 10%”.

Is the ethanol the only difference?

Winter vs summer has nothing... zero... to do with ethanol. It is the level of butane added to the fuel formula to improve winter vaporization for combustion. Summer, less butane. Gasoline is a formulation. Butane has a considerably lower BTU content and that is why winter blends typically will show drop off of mpg.

aseibel · February 16, 2018

On 2/14/2018 at 7:04 PM, Boardmember said:

Im getting about 15mpg, on exclusive highway, about 17. My prior trucks - one with 8sp, one with 6sp - did a lot better than this but had more miles.

What experiences have y’all had with mpg related to break-in periods?

Yes, you will probably notice an improvement in the numbers when they bring back the "summer blend". But is your new truck completely stock? or did you level it and put bigger, wider tires on? Any changes you make to the exterior, will likely cause loss of MPGs. Also, driving habits have alot to do with it and fuel efficiency tanks with high speeds. What is your average freeway speed? Your numbers are only a little lower than average, so I'm not convinced there's anything wrong with your truck, maybe some changes you can make.

aseibel · February 16, 2018

53 minutes ago, grizz_wi said:

Sounds like my MPG's, Im hoping its just the winter gas cause this is terrible. My trip on 2/11 was all highway going 65 and 55, DIC said my averago was 19.2

My lifetime average since owning this truck is 14.4, currently have 4500 miles.

Hell my average with my ole 94 is 13.3 and that has a 5.7

Do you remote start often? I don't believe the DIC calculates the fuel burned when you don't have the key in. That could also explain why you saw a 3mpg difference between the screen reading and your calcs.

Its winter in Wisconsin. During these cold stretches I frequently only get 15 mpg for a tank as well. In summer my average is more like 19-20.