My 6.2L mileage experience

[Blueinterceptor]

I was using ethanol free fuel for these results

 

[Blueinterceptor]

89 octane ethanol free Wawa gas

next I post some results for 93 octane premium with ethanol

 

[Blueinterceptor]

These were Highway miles only
with the exception of the of the driver summary which had 4 miles of non highway miles included

 

[GoNoGo]

My '23 Suburban HC with 6.2L trip-2 meter has never been reset since leaving Arlington factory.. so Hwy miles, rural miles, city miles, idling at drive-thru windows, occasional 10 minute morning warm-ups and etc is a Lifetime combined 16-mpg using only good Premium gas.






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[swathdiver]

We get better mpgs with some ethanol in the fuel. It cools the fuel down and acts as a knock retardant.

 

[Blueinterceptor]

We get better mpgs with some ethanol in the fuel. It cools the fuel down and acts as a knock retardant.

I haven’t experienced any knocks yet.

 

[Doubeleive]

I could drive it for a day and knock that in half

 

[swathdiver]

I haven’t experienced any knocks yet.

Not saying yours is but knocking is very hard to detect by ear these days, have to use a scan tool which gives more accuracy.

 

[Blueinterceptor]

Not saying yours is but knocking is very hard to detect by ear these days, have to use a scan tool which gives more accuracy.

I did not know that.

 

[DuraYuk]

Its not terrible for highway. My duramax averages 22 in the city and 30mpg on the highway. Lifetime mpg is somewhere around 26 with mostly city driving. Best I've gotten is 34mpg on the highway at about 75 mph.

 

[WalleyeMikeIII]

My '23 Suburban HC with 6.2L trip-2 meter has never been reset since leaving Arlington factory.. so Hwy miles, rural miles, city miles, idling at drive-thru windows, occasional 10 minute morning warm-ups and etc is a Lifetime combined 16-mpg using only good Premium gas.






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This matches my experience perfectly, including throwing in about 15% of the miles towing my 4500lb boat on the highway. I have only ever run Premium in mine.

 

[WalleyeMikeIII]

We get better mpgs with some ethanol in the fuel. It cools the fuel down and acts as a knock retardant.

The key to knock elimination is use the recommended octane to prevent detonation...Manual says minimum 91 for the 6.2.

93 is difficult to find in MN, but if I can get it, I'll use it. Usually get the 92 at Costco.

 

[swathdiver]

I did not know that.

A scan tool or OBDII adapter and phone app can even tell which cylinder and how many times.

 

[GoNoGo]

The Duramax Burb shows trip-2 lifetime (since factory) of 24-mpg but only has 1700 miles and may not be fully broken in.

Wish my '06 Silverado 6.6L Duramax got 24-mpg (rather than 14) LOL !!