Selecting the Right Octane Fuel for vehicles

[Old Ranchero]

I've never understood why there is debate. Ford says 87 octane is fine. For max power or towing Ford says use premium. That should be the beginning and end of the conversation.

Actually in the Ecoboost its better overall performance (not just max) AND better MPG running on 91. There just isn't any downside to it unless the minor extra cost breaks the bank for some reason.

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[TheWizziard]

I pull up to the gasoline pump and select the regular button.

 

[ejouie]

Actually in the Ecoboost its better overall performance (not just max) AND better MPG running on 91. There just isn't any downside to it unless the minor extra cost breaks the bank for some reason.

Unless you can notice a difference, it's a waste of $ for most of us. See the full quote below.

https://fueleconomy.gov/feg/octane.shtml

this seems especially relevant in consideration of never ending "debate" and opinions on what is best for our Mavericks. Enjoy!

Selecting the Right Octane Fuel

What is octane rating?

Gas pump showing octane options
Octane rating is the measure of a fuel's ability to resist "knocking" or "pinging" during combustion, caused by the air/fuel mixture detonating prematurely in the engine.

In the U.S., unleaded gasoline typically has octane ratings of 87 (regular), 88–90 (midgrade), and 91–94 (premium). Gasoline with an octane rating of 85 is available in some high-elevation areas of the U.S. (more about that below).

The octane rating is prominently displayed in large black numbers on a yellow background on gasoline pumps.

What octane fuel should I use in my vehicle?

You should use the octane rating required for your vehicle by the manufacturer. So, check your owner's manual. Most gasoline vehicles are designed to run on 87 octane, but others are designed to use higher octane fuel.

Why do some manufacturers require or recommend the use of higher octane gasoline?

Higher octane fuels are often required or recommended for engines that use a higher compression ratio and/or use supercharging or turbocharging to force more air into the engine. Increasing pressure in the cylinder allows an engine to extract more mechanical energy from a given air/fuel mixture but requires higher octane fuel to keep the mixture from pre-detonating. In these engines, high octane fuel will improve performance and fuel economy.

What if I use a lower octane fuel than required for my vehicle?

Using a lower octane fuel than required can cause the engine to run poorly and can damage the engine and emissions control system over time. It may also void your warranty. In older vehicles, the engine can make an audible "knocking" or "pinging" sound. Many newer vehicles can adjust the spark timing to reduce knock, but engine power and fuel economy will still suffer.

Will using a higher octane fuel than required improve fuel economy or performance?

It depends. For most vehicles, higher octane fuel may improve performance and gas mileage and reduce carbon dioxide (CO2) emissions by a few percent during severe duty operation, such as towing a trailer or carrying heavy loads, especially in hot weather. However, under normal driving conditions, you may get little to no benefit.

Why does higher octane fuel cost more?

The fuel components that boost octane are generally more expensive to produce.

Is higher octane fuel worth the extra cost?

If your vehicle requires midgrade or premium fuel, absolutely. If your owner's manual says your vehicle doesn't require premium but says that your vehicle will run better on higher octane fuel, it's really up to you. The cost increase is typically higher than the fuel savings. However, lowering CO2 emissions and decreasing petroleum usage by even a small amount may be more important than cost to some consumers.

What is 85 octane, and is it safe to use in my vehicle?

The sale of 85 octane fuel was originally allowed in high-elevation regions—where the barometric pressure is lower—because it was cheaper and because most carbureted engines tolerated it fairly well. This is not true for modern gasoline engines. So, unless you have an older vehicle with a carbureted engine, you should use the manufacturer-recommended fuel for your vehicle, even where 85 octane fuel is available.

Can ethanol boost gasoline's octane rating?

Yes. Ethanol has a much higher octane rating (about 109) than gasoline. Refiners usually blend ethanol with gasoline to help boost its octane rating—most gasoline in the U.S. contains up to 10% ethanol. Blends of up to 15% ethanol are available in some areas, and several manufacturers approve using this blend in recent-model vehicles.

 

[realshelby]

Knock sensors in engines detect detonation......

So, especially in EcoBoost engines under high boost pressure, your knock sensor will not be telling your engine ECU to retard timing as often when using 91+ octane vs 87 octane. Under load, your Ecoboost WILL make more power with 91+ octane. Since the engine ECU is happy that there is no detonation, it will maintain a more aggressive spark timing curve even at cruise and part load. This, and only this, is the reason running 91+ octane can net higher miles per gallon.
Fine. But do NOT think running 87 octane is bad for your engine. It IS recommended for regular use.

Bottom line is economy. Those of you that run 91+ Octane are paying more for fuel per mile than those using 87 octane. Do the exact math on this over time before writing a reply please. I have on a 3.5 Ecoboost and the cost to run premium fuel is notably higher per mile driven even with the slight increase in mileage.

I could never prove a difference in either power OR fuel mileage in the 2013 Cmax I bought new when trying 93 octane over 87 octane. Not surprised as that engine is naturally aspirated.

 

[olderbudwiser]

As it pertains to Hybrids if one uses the ice so little fuel sits for extended times, I would just look for non-ethanol fuel. There is an additional cost to pay for non-eth but if sitting in your tank for long periods it may be worth it. One should be able to find non-eth from 87-93 at various stations.

 

[realshelby]

Hybrids still use fuel! I simply don't see a reason to treat their fuel any different than any ICE vehicle. They have a system built to handle Ethanol, being fuel injected it is a fully sealed system so there is no air getting in to begin degrading fuel. Even 3-4 months without refueling should not degrade the fuel.
I would go several weeks without fueling the Cmax. Never an issue.

 

[GPSMan]

I would recommend 93 for the hybrids, simply because how long the gas is likely to stay in the tank. EBs should be fine on 89 unless you WFH like me.

This is bass ackwards.
I don't know how else to say it without getting banned. Please do not do this.

Hybrids are least suitable. Have the least need for higher octane due to the Atkinson cycle engine, and the fact the engine is never at high load.

Ran 85 octane in mine in Denver, for 14 years and 236,000 miles in my hybrid Escape. Even towed 3400 lbs with the hybrid Escape while using 85 octane. Never a dime of trouble.

I think it is impossible for hybrids to knock & ping (unless you get one with bad programming from the factory )

As an octane BOOSTER some markets have MORE ethanol in the premium than the regular gas.

If premium is 20 or 30 cents more, they are boosting with ethanol. If premium is 60, 80, or even 90 cents more, they are not boosting with ethanol so you're gonna pay out the ass for getting more gas.

 

[crgator]

Actually in the Ecoboost its better overall performance (not just max) AND better MPG running on 91. There just isn't any downside to it unless the minor extra cost breaks the bank for some reason.

It probably doesn't break the bank, but at $0.65 a gallon more, that's $7.80 more for a 12-gallon fill-up. I don't think the slight increase in mileage would offset that much of an increase in the cost of a fill-up. So unless using 91 prolongs the life of the engine (a lot) I don't see the need to spend that extra money when it runs great on 87. Shoot, I'll use that $7.80 to buy a six-pack of Guinness.

 

[commadorebob]

This is bass ackwards.
I don't know how else to say it without getting banned. Please do not do this.

Hybrids are least suitable. Have the least need for higher octane due to the Atkinson cycle engine, and the fact the engine is never at high load.

Ran 85 octane in mine in Denver, for 14 years and 236,000 miles in my hybrid Escape. Even towed 3400 lbs with the hybrid Escape while using 85 octane. Never a dime of trouble.

I think it is impossible for hybrids to knock & ping (unless you get one with bad programming from the factory )

As an octane BOOSTER some markets have MORE ethanol in the premium than the regular gas.

If premium is 20 or 30 cents more, they are boosting with ethanol. If premium is 60, 80, or even 90 cents more, they are not boosting with ethanol so you're gonna pay out the ass for getting more gas.

Sorry, I was just posting nonsense as a joke and it fell flat. I honestly put 87 in everything until it hits 150,000 miles, then I move up to 89 simply because I have found it recovers some performance.

 

[GPSMan]

Makes much more sense.

 

[MavDave]

https://fueleconomy.gov/feg/octane.shtml

this seems especially relevant in consideration of never ending "debate" and opinions on what is best for our Mavericks. Enjoy!

Selecting the Right Octane Fuel

What is octane rating?

Gas pump showing octane options
Octane rating is the measure of a fuel's ability to resist "knocking" or "pinging" during combustion, caused by the air/fuel mixture detonating prematurely in the engine.

In the U.S., unleaded gasoline typically has octane ratings of 87 (regular), 88–90 (midgrade), and 91–94 (premium). Gasoline with an octane rating of 85 is available in some high-elevation areas of the U.S. (more about that below).

The octane rating is prominently displayed in large black numbers on a yellow background on gasoline pumps.

What octane fuel should I use in my vehicle?

You should use the octane rating required for your vehicle by the manufacturer. So, check your owner's manual. Most gasoline vehicles are designed to run on 87 octane, but others are designed to use higher octane fuel.

Why do some manufacturers require or recommend the use of higher octane gasoline?

Higher octane fuels are often required or recommended for engines that use a higher compression ratio and/or use supercharging or turbocharging to force more air into the engine. Increasing pressure in the cylinder allows an engine to extract more mechanical energy from a given air/fuel mixture but requires higher octane fuel to keep the mixture from pre-detonating. In these engines, high octane fuel will improve performance and fuel economy.

What if I use a lower octane fuel than required for my vehicle?

Using a lower octane fuel than required can cause the engine to run poorly and can damage the engine and emissions control system over time. It may also void your warranty. In older vehicles, the engine can make an audible "knocking" or "pinging" sound. Many newer vehicles can adjust the spark timing to reduce knock, but engine power and fuel economy will still suffer.

Will using a higher octane fuel than required improve fuel economy or performance?

It depends. For most vehicles, higher octane fuel may improve performance and gas mileage and reduce carbon dioxide (CO2) emissions by a few percent during severe duty operation, such as towing a trailer or carrying heavy loads, especially in hot weather. However, under normal driving conditions, you may get little to no benefit.

Why does higher octane fuel cost more?

The fuel components that boost octane are generally more expensive to produce.

Is higher octane fuel worth the extra cost?

If your vehicle requires midgrade or premium fuel, absolutely. If your owner's manual says your vehicle doesn't require premium but says that your vehicle will run better on higher octane fuel, it's really up to you. The cost increase is typically higher than the fuel savings. However, lowering CO2 emissions and decreasing petroleum usage by even a small amount may be more important than cost to some consumers.

What is 85 octane, and is it safe to use in my vehicle?

The sale of 85 octane fuel was originally allowed in high-elevation regions—where the barometric pressure is lower—because it was cheaper and because most carbureted engines tolerated it fairly well. This is not true for modern gasoline engines. So, unless you have an older vehicle with a carbureted engine, you should use the manufacturer-recommended fuel for your vehicle, even where 85 octane fuel is available.

Can ethanol boost gasoline's octane rating?

Yes. Ethanol has a much higher octane rating (about 109) than gasoline. Refiners usually blend ethanol with gasoline to help boost its octane rating—most gasoline in the U.S. contains up to 10% ethanol. Blends of up to 15% ethanol are available in some areas, and several manufacturers approve using this blend in recent-model vehicles.

Probably really good information but for me.... TLDR, . I might take a bit of an old school approach here but. Turbo = the highest octane available, or at least ethanol free if it's close. I have yet to see the internals of a boosted engine with 100k+ that has run regular or even plus fuel that has been ok. Most are absolutely trashed, and I plan on keeping mine until the wheels fall off. As I typically do. If I were driving a hybrid I wouldn't think about putting anything but the cheapest fuel available.

 

[JimParker256]

<< snip >>
If I were driving a hybrid I wouldn't think about putting anything but the cheapest fuel available.

And that would also be a mistake, considering that lots of gas stations have E85 and 85-octane gasoline as their "cheapest fuel available". Both the hybrid and ecoboost call for 87 octane minimum, and E-85 is severely frowned upon..

It's fine for the turbo guys to "blow" their money on higher octane fuel (see what I did there?) if they believe it works better or somehow keeps it cleaner. But Ford specifically recommends against using fuels with lower-octane ratings than 87, or fuel with more than 15% ethanol, and specifically calls out E85 as not to be used, warning that those could cause issues that would not be covered by the warranty..

 

[MavDave]

And that would also be a mistake, considering that lots of gas stations have E85 and 85-octane gasoline as their "cheapest fuel available". Both the hybrid and ecoboost call for 87 octane minimum, and E-85 is severely frowned upon..

It's fine for the turbo guys to "blow" their money on higher octane fuel (see what I did there?) if they believe it works better or somehow keeps it cleaner. But Ford specifically recommends against using fuels with lower-octane ratings than 87, or fuel with more than 15% ethanol, and specifically calls out E85 as not to be used, warning that those could cause issues that would not be covered by the warranty..

I stand corrected... I wouldn't run E-85. What I should have said is the cheapest regular 85(ish) octane fuel available.

 

[Old Ranchero]

It probably doesn't break the bank, but at $0.65 a gallon more, that's $7.80 more for a 12-gallon fill-up. I don't think the slight increase in mileage would offset that much of an increase in the cost of a fill-up. So unless using 91 prolongs the life of the engine (a lot) I don't see the need to spend that extra money when it runs great on 87. Shoot, I'll use that $7.80 to buy a six-pack of Guinness.

So about the price of a fancy Starbutts coffee or Happy Meal vs. premium gas in my fillup? I don't do the 1st 2 and a tank lasts me weeks being retired. Yeah, I did highlight Turbo stuff specifically. That's what I have and shapes my thinking and choice that happens to agree with the article. Hybrids are invisible to me You do you. All good!

 

[bartflossom]

Regardless of the octane, I only use top-tier detergent gasoline. All Quik Trips and Costcos use top-tier and most "brand name" stations like Shell. Race-Trac does not. Most grocery stores like Kroger do not.

There is an emblem on the pump to look for.

With the loss of fuel vapor flowing over the back of the intake valves due to auto makers switching to direct injection into the combustion chamber, keeping carbon from building up on the valves is more problematic. My wife's Hyundai manual says top-tier is an absolute must in their vehicles, and I notice above that Ford recommends it too.

So when I put in my first tank this will be what I use. Thinking I'll probably go 89 octane with the heat in north Texas.

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