Worse m.p.g. Using higher octane

[Josebd]

Ok I give up,thanks

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[BassRanger]

Putting 87 in a small displacement turbo engine is not a good idea. No matter what Ford says.

What non-anecdotal data do you have to support this conclusion? That's a pretty bold claim. The Ecoboost platform has been out for over a decade. If there were widespread engine failure or damage from using lower octane fuel it would be common knowledge by now, wouldn't you think?

 

[D Fresh]

What non-anecdotal data do you have to support this conclusion? That's a pretty bold claim. The Ecoboost platform has been out for over a decade. If there were widespread engine failure or damage from using lower octane fuel it would be common knowledge by now, wouldn't you think?

Ford's system requires the knock sensor to sense a problem before the system will pull timing. Any amount of knock is not good for your engine. While that may not mean catastrophic failure, anybody with a rudimentary understanding can see that it is better to run higher octane fuel.

Now for the anecdotal. Ecoboost engines have received a lot of hate for their perceived problems. Talk to anybody that's ever had an Ecoboost problem, they aren't hard to find, and ask them 2 questions. Oil change interval and fuel type. The vast majority will say 87 and they followed the oil life monitor, or 10k miles.

Literally every other manufacturer requires premium in their small displacement turbocharged vehicles. Ford doesn't because they want to emphasize the "Eco" in Ecoboost.

I've driven small displacement turbo engines for over 15 years. All mine get full synthetic @ 5k and premium. But I like to take care of my expensive stuff.

 

[dtech]

Literally every other manufacturer requires premium in their small displacement turbocharged vehicles. Ford doesn't because they want to emphasize the "Eco" in Ecoboost.

That may have been true some yrs back but a growing number of small displacement turbos do just fine on regular grade gas - recent Mazda, Hyundai and KIA, Honda, Toyota, Subaru and GM turbos that aren't marketed as performance models can run on regular, some do recommend premium for max power production. Most have engine mgmt systems that are designed to run a range of octane levels above 87, however my Hyundai 2.0t is pretty much designed to run on 87 and see little benefit from higher octanes - because that's the way the ECU is programmed. But most mfgs now have designed the SW to adapt to a range of octane levels and the engines can run safely on 87 octane. Of late I've taken to running 87 in my Ranger - driven by the rise of gas prices.

 

[D Fresh]

That may have been true some yrs back but a growing number of small displacement turbos do just fine on regular grade gas - recent Mazda, Hyundai and KIA, Honda, Toyota, Subaru and GM turbos that aren't marketed as performance models can run on regular, some do recommend premium for max power production. Most have engine mgmt systems that are designed to run a range of octane levels above 87, however my Hyundai 2.0t is pretty much designed to run on 87 and see little benefit from higher octanes - because that's the way the ECU is programmed. But most mfgs now have designed the SW to adapt to a range of octane levels and the engines can run safely on 87 octane. Of late I've taken to running 87 in my Ranger - driven by the rise of gas prices.

In the very recent past I believe you. However, it's cheap enough insurance to run premium in my opinion. The fact that these systems will advance timing to a certain degree, adding performance gains to the equation, makes it an easy decision for me.

 

[dtech]

In the very recent past I believe you. However, it's cheap enough insurance to run premium in my opinion. The fact that these systems will advance timing to a certain degree, adding performance gains to the equation, makes it an easy decision for me.

Fair enough - but the engines controls and capability of the ECUs in today autos is orders of magnitude superior than decades ago , the ability to detect knock and nearly instantaneously change engine parameters is much due to leveraging the power of todays microprocessors - which also enable DI technology to be effectively used. I think replacing an ECU is typically around $1k or more these days, I think a lot are now using 64 bit microprocessors.

 

[D Fresh]

Fair enough - but the engines controls and capability of the ECUs in today autos is orders of magnitude superior than decades ago , the ability to detect knock and nearly instantaneously change engine parameters is much due to leveraging the power of todays microprocessors - which also enable DI technology to be effectively used. I think replacing an ECU is typically around $1k or more these days, I think a lot are now using 64 bit microprocessors.

Key word "nearly."

 

[DT444T]

Now for the anecdotal. Ecoboost engines have received a lot of hate for their perceived problems. Talk to anybody that's ever had an Ecoboost problem, they aren't hard to find, and ask them 2 questions. Oil change interval and fuel type. The vast majority will say 87 and they followed the oil life monitor, or 10k miles.

Literally every other manufacturer requires premium in their small displacement turbocharged vehicles. Ford doesn't because they want to emphasize the "Eco" in Ecoboost.

I've driven small displacement turbo engines for over 15 years. All mine get full synthetic @ 5k and premium. But I like to take care of my expensive stuff.

Ok and my brother has a 2012 F150 3.5EB with 180,000 on the clock and it's drank nothing but 87 its whole life and has towed a fair amount and he drives around with the big contractor box on the back of it that is enough of a load that he normally gets 15 mpg with it on. It has had ZERO mechanical problems.

My other car is a 300ZX turbo. That gets Premium, exclusively. Why? Older tech. The fact that my 2.3L makes similar HP and more Tq than a 30 year old Nissan shows the difference. Run premium all you want, I'm not gonna.

Very few NA engines have a high enough compression ratio to require higher octane fuels. Unless you're talking about motorcycles.

There are plenty of NA motors that NEED premium fuel that aren't motorcycles. There's high compression NA motors. Where did you get that idea?

 

[NeptuneRanger]

Knock arguments aside, from my personal experience going back and forth from AZ to CA burning a full tank and comparing 91 to 87, 87 gives me better MPG, this isn’t a one off, made the 375 mile drive fourteen times so far and will do so shortly. All my CA peeps can vouch for CA gas prices, got to hold both hands high in the air driving to the pumps, your wallet will be lighter on the way out. Thus it is 87 for me !

 

[D Fresh]

Ok and my brother has a 2012 F150 3.5EB with 180,000 on the clock and it's drank nothing but 87 its whole life and has towed a fair amount and he drives around with the big contractor box on the back of it that is enough of a load that he normally gets 15 mpg with it on. It has had ZERO mechanical problems.

My other car is a 300ZX turbo. That gets Premium, exclusively. Why? Older tech. The fact that my 2.3L makes similar HP and more Tq than a 30 year old Nissan shows the difference. Run premium all you want, I'm not gonna.

For sure. Do as you please. Like I said, cheap insurance IMHO.

There are plenty of NA motors that NEED premium fuel that aren't motorcycles. There's high compression NA motors. Where did you get that idea?

Of corse there are. But not many that are factory installed in automobiles. And none in US midsized trucks.

 

[ScrappyLaptop]

Fair enough - but the engines controls and capability of the ECUs in today autos is orders of magnitude superior than decades ago , the ability to detect knock and nearly instantaneously change engine parameters is much due to leveraging the power of todays microprocessors - which also enable DI technology to be effectively used. I think replacing an ECU is typically around $1k or more these days, I think a lot are now using 64 bit microprocessors.

As far as I know most are 32-bit, usually RISC, with a built in DSP. I'm guessing based on corporate relationships Ford might be using something like the Infineon 32-bit AURIX TriCore mcu? Plenty fast & powerful enough.

But they still detect ping/detonation based on either sound or more recently & experimentally, on changes in ion current flow. But even with that rather advanced method an entire cycle of ping must occur for it to be detected & reacted to. If the engine were constantly running on that edge, that's a lot of pinging that is allowed to happen and it can still be detrimental. But also, any time the ECU has to de-tune to avoid knocking, power & mpg will drop. My guess is they program in safe ranges for expected octane levels rather than always pushing to the limit at any given moment & fuel.

Here's a good, quick primer on octane:

https://us.etsracingfuels.com/blogs/blog/guide_to_racing_fuels_the_octane_factor?loc=us

My one problem with it is where it says, "So an octane rating of 93 indicates the fuels contains 93% iso-octane and 7% heptane" what they really mean is, "So an octane rating of 93 indicates the fuel being tested behaves the same as 93% iso-octane and 7% heptane when it comes to knock/ping".

 

[Josebd]

The dealer I bought it from never mentioned using 87 octane,so with people that don’t have mechanical experience,and this younger generation,women,etc….. are not going to even think about opening the owners manual,or get online and listen to so many different opinions,there going to buy the cheapest gas they can find,and in my area it’s going to be 86 octane.

 

[dtech]

As far as I know most are 32-bit, usually RISC, with a built in DSP. I'm guessing based on corporate relationships Ford might be using something like the Infineon 32-bit AURIX TriCore mcu? Plenty fast & powerful enough.

But they still detect ping/detonation based on either sound or more recently & experimentally, on changes in ion current flow. But even with that rather advanced method an entire cycle of ping must occur for it to be detected & reacted to. If the engine were constantly running on that edge, that's a lot of pinging that is allowed to happen and it can still be detrimental. But also, any time the ECU has to de-tune to avoid knocking, power & mpg will drop. My guess is they program in safe ranges for expected octane levels rather than always pushing to the limit at any given moment & fuel.

Here's a good, quick primer on octane:

https://us.etsracingfuels.com/blogs/blog/guide_to_racing_fuels_the_octane_factor?loc=us

My one problem with it is where it says, "So an octane rating of 93 indicates the fuels contains 93% iso-octane and 7% heptane" what they really mean is, "So an octane rating of 93 indicates the fuel being tested behaves the same as 93% iso-octane and 7% heptane when it comes to knock/ping".

just as an FYI on ion detection to control knock - I'm familiar with that as it was introduced on Saabs in the 1990s, a joint development with a Swedish University. The main advantage over acoustic knock detection is that it passes an ion measuring current pre combustion over the spark plug gap and can make timing adjustments on each cylinder to prevent knock from occurring, last I heard only BMW and Bugatti were employing it, I think the license cost is high plus what I referred to with the advances in microprocessors acoustic detection has become effective in controlling knock.
And from what I recall reading timing isn't continually advanced and retarded, but the ecu makes periodic reads to determine baseline octane and adjusts accordingly.

 

[Racket]

I think it makes sense to suggest that the stock tuning enables the engine to run with pretty much any octane. Fine tuning tightens performance but narrows fuel choices.

 

[dtech]

Link to C&D article - electronics now comprise 40% of cost in vehicles today:

https://www.caranddriver.com/features/a32034437/computer-chips-in-cars/

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