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

[Jmav2152]

Turbos
Turbos don't do anything with A/F or the ratio. They just provide pressurized air. The throttle body/injectors are what take care of the mixture. I get your point on pre-detination but these motors are tuned for 87 and should have zero issue with that.

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[Jmav2152]

My bad i thought you were replying to my post above. I'm picking up what your putting down now.

 

[mamboman777]

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.

Nice work. Thank you for sharing. Seems about right and I respect you for your thoroughness.

 

[JASmith]

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

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

But Costco also has cheap Regular. Hemi is rated for mid-grade, so I do regular for most of the year and premium during peak summer scorching heat.

 

[Vinhnguyen54]

One more thing to think about Premium fuel has much more cleaning additives then regular.
Especially if you are using top tier gas. Always get gas at costco normally less than 10 cent per gallon difference vs regular at other stations. If you plan on keeping the Maverick till the wheels fall off then, IMO its totally worth it. On Mini Cooper S it would get 3-4 MPG better with premium, so the cost difference was really Nil. Will be putting 93 in my Mav!

3-4 mpg difference?! I didn't know premium can make such a huge diff on a stock tune.

 

[JSanchez]

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...

It’s not stupid if your gas is as cheap as you’re stating. California is at least a dollar more expensive. Arco is roughly 4.35 for the cheap stuff, Costco is roughly 4.24.

 

[Naranjita]

It’s not stupid if your gas is as cheap as you’re stating. California is at least a dollar more expensive. Arco is roughly 4.35 for the cheap stuff, Costco is roughly 4.24.

At Fred Meyer when I fueled up tonight it was $4.09 for 92 octane, and $3.84 for 87.

 

[BlueSnake77]

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.

I would change it sooner. With the ecoboost, I would change the oil every 4k miles. The hybrid every 5k. I would never go over 5k on oil changes, the heck with what the manual says.

 

[Guv]

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.

It will indeed help the turbo. When lower octane fuel causes the ECU to retard timing several things happen:
Spark timing is retarded, this can cause increased exhaust gas temperatures. When you retard timing, higher exhaust temps will increase boost, adding to the problem
This will cause the ECU to richen the fuel mixture (not good for MPG) to lower exhaust temps or
Close the throttle, open the wastgate or a combination of all above .
Lowering turbo boost pressure is the goal to let the engine get out of knock
If you are a conservative driver (light on the gas), the above situation is less likely to occur.

 

[nick112288]

What amazes me is some of you are happy with mileage that is the same as my 95 Ram diesel!

Granted it's 2wd and completely stock but even then it's got 4.10 gears and will get hand calculated 26mpg on the highway and 21 to 24 mix depending on how much city I do!

I was considering the 2.0 AWD but I'd have to get around 30 on the highway to be worth it to me.

 

[Sjbuck2021]

I've run 87 in all the vehicles I've owned with the exception of a vw which I used 89. Once in a while I filled up with 92. Absolutely no difference in fuel economy or engine noise. Also 87 contains the same amount of detergents as 92...no difference except octane level. Run 92 in the eb and 87 is perfectly fine for the hybrid.

 

[uh50]

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.

Great question. It'll be interesting to see the answer.

 

[NJBob]

You are correct. I have a 69 Z/28 that requires 95 octane. Octane booster turns the plugs orange. Used to use Sunoco 260 think that was like 97 Octane.

 

[jc888888888]

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

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

Here in Florida BJ,s wholesale club sells premium 93 octane ,fo apx( give or take a penny or two) the same cost as regular at other service stations.

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