6.2 MPG

drucker · August 31, 2020

My service engine light came on last Thursday afternoon so I figured I would try and experiment and it worked this time. I went to the lake and this town doesn't have high octane gas because most stations have non-ethanol in the place on 93 octane. After running non-ethanol for about 50 miles my service engine light cut off.

Last Friday I cleared my trip calculator and went out of town (168 miles) and got 20.8 mpg on 93 octane.

I waited until my low fuel light came on and filled up with 90 octane non-ethanol. I cleared my trip calculator again drove the same route (168 miles) home and got 22.6 mpg.

TNTSierra · August 31, 2020

4 minutes ago, drucker said:

My service engine light came on last Thursday afternoon so I figured I would try and experiment and it worked this time. I went to the lake and this town doesn't have high octane gas because most stations have non-ethanol in the place on 93 octane. After running non-ethanol for about 50 miles my service engine light cut off.

Last Friday I cleared my trip calculator and went out of town (168 miles) and got 20.8 mpg on 93 octane.

I waited until my low fuel light came on and filled up with 90 octane non-ethanol. I cleared my trip calculator again drove the same route (168 miles) home and got 22.6 mpg.

So with lower octane you got better FE? Interesting. I’ve been told by my neighbor by my lake house who is the sales manager at Billion Auto that he has never put premium fuel in any of his 6.2L’s that he has owned or driven from lot and has never had a problem running just regular unleaded. I have always just put premium in my 6.2L because I want the maximum amount of performance out of it. Would love to hear what others are doing.

drucker · August 31, 2020

2 minutes ago, TNTSilverado said:

So with lower octane you got better FE? Interesting. I’ve been told by my neighbor by my lake house who is the sales manager at Billion Auto that he has never put premium fuel in any of his 6.2L’s that he has owned or driven from lot and has never had a problem running just regular unleaded. I have always just put premium in my 6.2L because I want the maximum amount of performance out of it. Would love to hear what others are doing.

I have always ran 93 in mine. I have 38xxx miles with lifetime 18.1 mpg. I have never cleared my trip A just so I can compare it with my 2014 5.3 which had 14 mpg.

BlancoSilverado · August 31, 2020

Going up hill/headwind (on average) for trip one, going down hill/tail wind (on average) for trip 2.

I took a trip going south for 80 miles then immediate north after picking up a new bicycle(under tunnel cover). i was getting 24-25mpg on the way there and 16-18mpg on the way back. The wind was that aggressive and it was on average down hill on the way there.

** Take the trip again but reverse the type of fuel you were using and see what happens. **

Edited August 31, 2020 by BlancoSilverado
** added more info**

drucker · August 31, 2020

29 minutes ago, BlancoSilverado said:

Going up hill/headwind (on average) for trip one, going down hill/tail wind (on average) for trip 2.

I took a trip going south for 80 miles then immediate north after picking up a new bicycle(under tunnel cover). i was getting 24-25mpg on the way there and 16-18mpg on the way back. The wind was that aggressive and it was on average down hill on the way there.

** Take the trip again but reverse the type of fuel you were using and see what happens. **

I have taken this trip several times and I have never gotten over 21 mpg either direction with with 93. Most of the time it will be around 19.5-20.5 mpg. I usually go to the lake about once or twice a month. This is the first time I have used non-ethanol.

Edited August 31, 2020 by drucker

ThatredneckguyJamie · August 31, 2020

I drive to work up hill in the snow both way in the Florida heat with a strong Santa Ana headwind. I'm getting around 18.3 average per the trip for the life of my truck about 8k miles. I've manually checked the mileage and it's usually been .2+/- accurate. I have run 93 since my first tank.

SkiDooNick700 · August 31, 2020

Isn't there a difference between a 93 octane 10% ethanol vs 90 octane no ethanol? I'm not a tuner or anything but 90 octane is practically "premium".

I think you'd be better off running 90 ethanol free vs 93 with ethanol, but I have no evidence to support this.

Generally these ethanol free fuels are noticeably more expensive than 10% ethanol so I always opt to fill with the 10% mix, plus, thats all thats available around me lol.

Colossus · September 1, 2020

Eh... the ethanol won't hurt fuel economy as much as it will performance. On direct Injection engines, turbocharged, and supercharged engines, it is strongly advised to run premium for several reasons.

1. Premium fuels from top tier stations will have the greatest amount of additives in them to help keep the fuel system clean and to help with carbon deposits. Carbon deposits are a BIG issue on DI engines and in addition to running top tier fuel, you should also be looking at having carbon cleaning services performed every year or so. And no, this is not a gimmick or snake oil- it is a proven FACT.

2. The computers on modern vehicles often will take advantage of the higher octane to adjust timing and other parameters to allow for better performance and often, better fuel economy.

3. These DI engines from all of the manufacturers were designed around and programmed around premium fuel, which is why you find the recommendations in the owners manual to be running premium. Sure, they will run off of 89/87, and for us up here at altitude, 85, octane, but even with knock sensors, sometimes you sure as hell hear the knocking!

blckblt · September 1, 2020

I have run both 90 eth free and 93 in my truck. 93 seems to be better performance wise and higher MPG.

Colossus · September 1, 2020

One more thing I've noticed which obviously you folks are seeing. Some vehicles just flat out run better on different grades of octane! Some do great with the best fuel economy on mid grade, some do best on premium, and some you won't notice any difference at all and can get away with regular grade. Here in Colorado we have 85, 87, and 91. Down at sea level, that would translate to 87, 89/91 and 93. (I've seen some 87/89/93 and some 89/91/93) While the Because fuel burns differently the higher you go in elevation, (and performance decreases due to less oxygen density) my pre-GDI non-turbo/supercharged engines ran best with 85. But these were lower compression engines too for the most part.

I could run 85 Octane in the 71 Buick Riviera with the 455, the 85 Nissan Stanza with the 2.0L 4 banger, the 88 Plymouth Voyager(aka Dodge Caravan) with the Mitsubishi 3.0L, the 1991 Buick Regal and 1994 Pontiac Grand Prix with the 3.1L (series II and III) The 1992 Ford Exploder with the trusty 4.0L, The 1996 Dodge Caravan with the 3.3L, The 1993 Caprice 9C1 Police Package with the 5.7L, the various Clown Victorias I've owned all with the 4.6L, (some police interceptor, some not, but essentially the same 4.6L engine) My 1999 Silverado, 2005 Sierra, 2007 Sierra, with the 5.3L, and the 2001 Sierra with the 4.8L, a 2013 Impala with the 305HP 3.6L direct injection engine, and my current beater, a 1997 Lumina with the 3.1L that I drive to keep miles down on the Duramax.

Out of all of those vehicles, Only my 97 Lumina seems to do slightly better with premium 91 from Costco vs standard 85 Octane. Why? I have no clue.

Now, when I did run E-85 the few times in my 2013 Impala, it made a VERY noticeable difference in performance (as well as reduced fuel economy, but duh to that) But that was a direct injection flex fuel engine which was designed to take advantage of that E-85. (Remember that E-85 means the amount of ethanol in the fuel, not octane rating) But between 85 octane and 91 octane, I did not notice too much except the occasional slight pinging on certain brands of 85 octane fuel. Each station brand such as Shell, Phillips 66, Chevron, Costco uses their own detergents/add packs which get added at the terminal where the tankers fill up, and then head out to the station. The base fuel may come from the same refinery but the ad packs/detergents added to the fuel going into the tanker are brand specific or meet a certain requirement, so the tanker truck driver or terminal technician will add the additives specific to the delivery station and it's octane rating as the fuel is added to the tanker, or once the tanker has been filled with the base fuel and then the additives are dropped in the sections of the tank based upon what octane rating is in there as higher rated octane generally gets different additives vs whats in base regular grade. What is dropped into the ground tanks at your neighborhood Phillips 66 is not going to be the same thing as what is dropped into your ground tanks at your local grocery store fuel island. The base fuel and octane may be the same, but the additives are not, and the additives are what makes the big difference.