Octane rating vs fuel consumption

It was on the Internet so it must be true. Personally and only in my opinion, I've tested the difference between Reg and Prem, each for a month but even that isn't perfect or anything that bears any weight. I got a slightly better mpg with Prem but like .5 better and when you count in that Prem is usually .50 to .70 cents more, it ends up actually being a loss. Plus I really don't notice any difference in performance, think it mostly in my mind even if I do. To me all this is so subjective that people will be discussing this topic forever

Ruger said:

Harblar, did you read those four articles?

Just askin', because I went to the trouble to provide articles from four different sources, they all came to the same conclusions, and it was quite clear that their frame of reference was vehicles with modern engine and fuel management systems.



BTW, the Ford manual makes it clear that peak torque is unchanged regardless of fuel.

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Ruger, have you tested 87 vs 91 for yourself? You can post all the articles you want, but they don't mean much when real world data in the Raptor from multiple end users tells you otherwise.

When my Raptor was stock I saw mpg as high as 15.5 mpg (usually around 14mpg or better) on 91. I never saw better than 11.3 mpg using 87.

My cost for 87 is $.35 per mile. My cost for 91 is $.33 per mile (and that figure includes almost 10,000 miles of driving with long tubes, cold air, a tune, and big damn heavy 36" Toyo's. My current mpg with that setup is around 11.7mpg, which is still better than I ever got with 87. If I loaded an 87 performance tune for my rig, I bet it'd fall down to less than 10mpg running 87.)


Wilson, I've only used E30 once. I was up in Britton and it was either 87/89 or e-30. I didn't have my tuner with me so e-30 was as close to 91 as I could get. It ran ok. The mileage wasn't quite as good, but I'm sure a proper tune for e-30 would help that. It did seem to have a pretty good snap to it.

Yes, Harblar, I have tested the two and found no difference. I've done it several times, too. But of course I know that any test without benefit of calibrated test equipment and a closed course isn't a test at all.

I answered your question. Now you answer the question I already asked you - did you read those 4 articles before you responded? Be honest.

Just for fun, here are some entertaining quotations from the good people who designed and built our trucks:

"If you experience starting, rough idle or hesitation driveability problems during a cold start, try a different brand of "Regular" unleaded gasoline. "Premium" unleaded gasoline is not recommended for vehicles designed to use "Regular" unleaded gasoline because it may cause these problems to become more pronounced." (page 393 under Maintenance and Specifications in the F-150 Owners Guide)

From the F-150 Supplement (page 7):
Engine Information 6.2L V8 Engine
Torque: 434 lb-ft @ 4500 rpm on 87 octane, 434 lb-ft @ 4500 rpm on 91 octane. [NOT a typo. The torque output of the engine is not improved when using 91 octane fuel. Owners who tow frequently take note.)

Ruger just cracks me up.....LOL

Glad to provide the morning's entertainment for you gents.

BTW, how do you precisely measure the amount of fuel actually used in an owner's fuel economy "test?" At the pump? (snicker)

What do you use to accurately measure mileage driven? The odometer in the dash? That's good. How do you calibrate it?

How do you standardize the test drives so that they are the same in all parameters so that they are not a factor in the "test?"

Obviously you make sure that temperature, humidity and barometric pressure are unchanged from test run to test run. I'd be interested in learning how you do that, please.

Okay, enough snark. These questions simply demonstrate that a seat-of-the-pants owner's 'test" is vastly different from a scientific one. The former produces opinions, the latter produces reliable data.

Smile. Enjoy your morning.

Im with ruger on this one...when the differences are around a few cents per gallon, the data is hardly accurate. Too many variables.

I have put 87 and 91 in mine and don't notice a difference.

$1.99 right now for e-85 for my thirsty 5.4 and it runs like a totally different truck on it. but yes MPG suks ***

Agent 00 L said:

The good stuff is the aviation gasoline, 118 Leaded and a pretty blue color!

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Smells good too. Too bad it's $17 a gallon.

E-30 smells good and is clear means it's free of pollutants

Bunch of huffers