2.0 MPG gas mileage tests (so far) and differences using 87 vs 92 octane

[Big Kahuna]

Everyone is all over the map with their gas milage so everyone can take this data with a grain of salt. It's simply my data.

XLT 4K AWD FX4 Ecoboost - 80% highway 20% city

Autostop Eliminator installed so my vehicle never turns off at lights.

Hand calculated numbers below. Car was very close on calculations.

Only did two tanks of gas of each so this is very preliminary data.

92 Octane - 28.0 MPG avg (car showed 28.3)
87 Octane - 27.0 MPG avg car showed 27.2)

$3.85 for 92 octane x 16 gallons = $61.60
$3.45 for 87 octane x 16 gallons = $55.20

If I use 87 octane for a fillup I save $6.40.

16 gallon tank - so with 92 I might get 16 miles more distance per tank

$3.45/27mpg = $0.127 x 16 = $2.032 to get the extra 16 miles with 87 octane

$6.40-$2.03= $4.37

So by my calculations if I use 87 octane I save $4.37 every fill up. Fill up every 10 days avg = $159.51 per year saving for using 87 octane.

Things I noted -

• Manual recommends 92 octane for best MPG performance and overall engine performance/HP but 87 is acceptable per the manual
• The engine definitely seemed slighly noisier and more "ticky" when running 87 vs 92 but this could also be a placebo effect
• I didn't notice any difference in performance but I drive like a grandma most of the time. It will be interesting to try towing with both octanes at some point.

I plan to own this truck for 10+ years and plan to run 92 as turbos are desgined to run better with higher octane. My view is that although the car has knock sensors it was designed to work best with 92+ and running it that way for 10 years may result in less wear in the long term. The 10 year cost for gas difference would be $1500 at current prices. Everyone can make their own assumptions about whether or not that is worth it vs possible repairs or wear.

If I only planned to have the truck for 5 years or didn't have the extra dough to spend on gas I would definitely roll with 87 octane. If gas prices continue to go up I might go that route as well. Lots of variables.

Sponsored

 

[Naranjita]

Everyone is all over the map with their gas milage so everyone can take this data with a grain of salt. It's simply my data.

XLT 4K AWD FX4 Ecoboost - 80% highway 20% city

Autostop Eliminator installed so my vehicle never turns off at lights.

Hand calculated numbers below. Car was very close on calculations - showed 28.3 for 92 octane and 27.2 for 87.

Only did two tanks of gas of each so this is very preliminary data.

92 Octane - 28.0 MPG avg
87 Octane - 27.0 MPG avg

$3.85 for 92 octane x 16 gallons = $61.60
$3.45 for 87 octane x 16 gallons = $55.20

If I use 87 octane for a fillup I save $6.40.

16 gallon tank - so with 92 I might get 16 miles more distance per tank

$3.45/27mpg = $0.127 x 16 = $2.032 to get the extra 16 miles with 87 octane

$6.40-$2.03= $4.37

So by my calculations if I use 87 octane I save $4.37 every fill up. Fill up every 10 days avg = $159.51 per year saving for using 87 octane.

Things I noted -

• Manual recommends 92 octane for best MPG performance and overall engine performance/HP but 87 is acceptable per the manual
• The engine definitely seemed slighly noisier and more "ticky" when running 87 vs 92 but this could also be a placebo effect
• I didn't notice any difference in performance but I drive like a grandma most of the time. It will be interesting to try towing with both octanes at some point.

I plan to own this truck for 10+ years and plan to run 92 as turbos are desgined to run better with higher octane. My view is that although the car has knock sensors it was designed to work best with 92+ and running it that way for 10 years may result in less wear in the long term. The 10 year cost for gas difference would be $1500 at current prices. Everyone can make their own assumptions about whether or not that is worth it vs possible repairs or wear.

If I only planned to have the truck for 5 years or didn't have the extra dough to spend on gas I would definitely roll with 87 octane. If gas prices continue to go up I might go that route as well. Lots of variables.

I ran one tank on 87. Didn't like it. Been running 92 ever since. I can afford it. I have run 92 in almost every turbo I've ever owned. Seems to run better. And I'm still paying way less for fuel than my Lincoln pickup.

Now queue the people telling us we're stupid and wasting money...

 

[Big Kahuna]

I ran one tank on 87. Didn't like it. Been running 92 ever since. I can afford it. I have run 92 in almost every turbo I've ever owned. Seems to run better. And I'm still paying way less for fuel than my Lincoln pickup.

Now queue the people telling us we're stupid and wasting money...

The interesting part is that I didn’t start the 87 test on purpose. My wife filled it up and I was on a trip and got back and thought, the truck seems more noisy than I remembered. Then we figured out she had put 87 in it so I figured I’d do the test. In my opinion it definitely performs better with 92 but if you want to save money the MPG argument doesn’t hold up and 87 is the way to go.

 

[Allen King Jr]

Great write up, easy to read and understand!

 

[Jimmy P]

Great job, very pertinent info, interesting to us EB owners, easy to follow. I love a well-written article that boils down tech info.

I'm still under 1k miles; on my 3rd tank, 1st was dealer fill-up which I'm sure was regular, 2nd fill was 92 octane, 3rd was 87 octane. I thought I noticed more noise on start-up/warm-up with 87, but the truck is still new to me. Also, it seemed not quite as punchy but I have no acceleration times to support/compare. I'll use 92 in next fill and see what I observe.

BTW, this is my 1st turbo ever, so I appreciate the reminder about potential longevity on higher octane fuel. The minor savings with 87 does not sway me. I want what's best for the truck (and me!).

 

[Nighowl2000]

Mines also noisy at startup but it's a direct inject. Just make sure to change oil at 5-7k not 10k +. Also I live in Canada right now and it's $1.50 a litter (about 5$ a gallon) so worth me sticking with 87 octane.

 

[pxpaulx]

Thankfully I don't have to make this choice at the moment...

Regular gas stations - $3.35 for Regular
Costco - $3.09 for Premium

 

[WhiteMaverick12]

Appreciate this information. Curious, would using octane booster be cheaper? I've always assumed it was far inferior to premium fuel.

 

[pxpaulx]

Agreed this is a critical component. It also allows comparison to the EPA testing process - with a time+distance driven component, it helps to provide additional context, though there are still other factors at play (cold starts, short trips) that can only be anecdotally provided.

 

[WhiteMaverick12]

Thanks for this info!

 

[Portcqb]

Everyone is all over the map with their gas milage so everyone can take this data with a grain of salt. It's simply my data.

XLT 4K AWD FX4 Ecoboost - 80% highway 20% city

Autostop Eliminator installed so my vehicle never turns off at lights.

Hand calculated numbers below. Car was very close on calculations - showed 28.3 for 92 octane and 27.2 for 87.

Only did two tanks of gas of each so this is very preliminary data.

92 Octane - 28.0 MPG avg
87 Octane - 27.0 MPG avg

$3.85 for 92 octane x 16 gallons = $61.60
$3.45 for 87 octane x 16 gallons = $55.20

If I use 87 octane for a fillup I save $6.40.

16 gallon tank - so with 92 I might get 16 miles more distance per tank

$3.45/27mpg = $0.127 x 16 = $2.032 to get the extra 16 miles with 87 octane

$6.40-$2.03= $4.37

So by my calculations if I use 87 octane I save $4.37 every fill up. Fill up every 10 days avg = $159.51 per year saving for using 87 octane.

Things I noted -

• Manual recommends 92 octane for best MPG performance and overall engine performance/HP but 87 is acceptable per the manual
• The engine definitely seemed slighly noisier and more "ticky" when running 87 vs 92 but this could also be a placebo effect
• I didn't notice any difference in performance but I drive like a grandma most of the time. It will be interesting to try towing with both octanes at some point.

I plan to own this truck for 10+ years and plan to run 92 as turbos are desgined to run better with higher octane. My view is that although the car has knock sensors it was designed to work best with 92+ and running it that way for 10 years may result in less wear in the long term. The 10 year cost for gas difference would be $1500 at current prices. Everyone can make their own assumptions about whether or not that is worth it vs possible repairs or wear.

If I only planned to have the truck for 5 years or didn't have the extra dough to spend on gas I would definitely roll with 87 octane. If gas prices continue to go up I might go that route as well. Lots of variables.

If you plan on keeping it 10 years make sure you are doing aggressive oil changes with full synthetic or you will be due for induction cleaning before 10 years. They are only direct injection and don't have a port injector to help clean the valves like some of the redesigned ecoboost engines.

 

[rlhdweman]

My question is, were both fuels E-10, as where is live the 87 is E-10 & the 91 is mostly not, & even though most of my vehicles don't need or require 91, they get 10%-15% better mpg with the 91 because of no ethanol content.

Sponsored