89 Octane

MrSticker said:

Im surprised at the magnitude of the mpg increase here, but not the concept. 07XLN explained here a while back that the Ecoboost engine technology has the ability to adjust engine operating parameters and optimize combustion to the octane level. For example the timing can be advanced for higher octane fuels without knocking ... More efficient combustion and better mpg. He can explain it a lot better than me. I'm an antique trying to catch up with new technology.

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It’s not so much that it changes to run better with higher octane it’s more that it’s designed to run on higher octane, and it’s peak power output and fuel economy (manufacturer figures) are achieved on premium fuel. When you put in lower octane fuel the motor retards timing. It’s all in the Variable Cam Timing on these modern motors.

Put 93, in it on our trip out to PA averaged 17.3 MPG. I averaged 14.1 going back and forth to work using 87.

Around me 87 octane is hovering about $2.98/gallon. 93 is $3.65 to $3.75/gallon. $15.00 or so extra per tank for 93. I use 87 most of the time with an occasional 93 fill up. 93 only when towing.

My '16 Expy I only run Top Tier fuel such as Shell Premium or Mobil since the day I drove it off the lot. I like the all around engine performance that makes up for the missing 2 cylinders. Makes the truck fun to drive.

Always run BP Ultimate 93 octane. Clear fuel that will keep the system cleaner. That’s right from a chemical engineer in the family. I run nothing but BP 93 and I also have a K&N air filter. 21 MPG average now with 9400 on the clock..

Helo driver said:

Always run BP Ultimate 93 octane. Clear fuel that will keep the system cleaner. That’s right from a chemical engineer in the family. I run nothing but BP 93 and I also have a K&N air filter. 21 MPG average now with 9400 on the clock..

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BP is also my choice of fuels, we have company cards for BP, Shell and Mobil. All my vehicles have K&N air filters.

I ran tanks of 87, 89, and 93 in my 2017 to check the mileage. I don't have the numbers in front of me, but the higher the octane, the better the MPG. Ran a bit stronger too. I calculated the cost per mile for each. 89 was about $.15 a mile and 93 was about $.17 a mile to drive.

Yep, the EcoBoost engines are well documented to put out more power and get more mpg with higher octane fuels. The question remains a matter of economics. Dan's experience indicates 93 octane costs 12% more per mile than 89. And, I'm sure, even more than 87 which runs fine in my truck.

Ya gotta decide what's good enough for your use. For me that's good ole 87. I have another car that requires (and is tuned for) 93 Octane and this runs a consistent 60¢/gallon more than 87 here in Virginia regardless of the price of 87.

-- Chuck