93 Worth It?

[propelledjeans]

Hey everyone.

 

Just got a 2010 Fusion yesterday (woo!) and was curious about which gas to put in it. I've done some searching on the forums and read that "93 hurts the car" or "93 is better for the car" or "just put 87" etc.

 

Which should I believe? Which do you recommend?

 

Thanks in advance,

 

James

[bbf2530]

Hey everyone.

 

Just got a 2010 Fusion yesterday (woo!) and was curious about which gas to put in it. I've done some searching on the forums and read that "93 hurts the car" or "93 is better for the car" or "just put 87" etc.

 

Which should I believe? Which do you recommend?

 

Thanks in advance,

 

James

 

Hi James. :D This is the best advice I can give: Read your Owners Manual. Look in the Index under "Fuel", then "choosing the right fuel". There you will find the page number for the section concerning what types of fuel to use. You will find that it specifically states that our cars are designed to use 87 octane regular fuel. You will also see that it specifically states not to use premium fuels as they can cause engine issues, or make existing issues even worse.

 

Short story is that our engine management system is not designed for nor capable of adjusting for higher octane fuels. It simply can not take advantage of the "detonation resistance" (or other performance benefits) of higher octane fuels. Therefore, not only are you throwing money away by paying higher prices for premium, use of premium fuels may also lead to engine issues.

 

Of course, some people feel differently, and they are free to do as they like with their own cars. However, in the end, it all comes down to this: Don't blindly believe me or anyone else. Instead, read your Owners Manual and do what the people who designed and manufactured your vehicle (Ford) tell you is best for your car.

 

Hope this information helps.

 

Good luck. :beerchug:

Edited December 19, 2010 by bbf2530

[Oldguy16]

Like bbf said, everyone has their own opinions. Personally I put 93 in my Fusion because I see a noticeable difference in the way it runs. But this is just me, not looking to tell you what to do at all. The Fusions can run on 87, however the Fusion 3.0 is also a flex fuel, and ethanol is a very high octane. I believe somewhere in the high 90's. Ethanol is not 85 octane, that only stands for 85% ethanol and 15% gasoline. I'm pretty sure this is correct. Ethanol burns hotter, and I'm almost certain the octane rating is very high. That said, it seems that this engine can take different fuels. My personal opinion, and my opinion only, I feel it runs better on premium. Best would be however, and I think we can all agree, pick a type of fuel and stick with it. Good luck! Let us know what you choose.

[propelledjeans]

Thanks! (to both of you)

 

87 it is! :P

[jazztrumpet216]

Like bbf said, everyone has their own opinions. Personally I put 93 in my Fusion because I see a noticeable difference in the way it runs. But this is just me, not looking to tell you what to do at all. The Fusions can run on 87, however the Fusion 3.0 is also a flex fuel, and ethanol is a very high octane. I believe somewhere in the high 90's. Ethanol is not 85 octane, that only stands for 85% ethanol and 15% gasoline. I'm pretty sure this is correct. Ethanol burns hotter, and I'm almost certain the octane rating is very high. That said, it seems that this engine can take different fuels. My personal opinion, and my opinion only, I feel it runs better on premium. Best would be however, and I think we can all agree, pick a type of fuel and stick with it. Good luck! Let us know what you choose.

 

E85 is typically 105 octane. But you're comparing apples to oranges because they're two very different fuels.

 

Personally- I'm a teacher, not an engineer. I would run what the owner's manual says. If it says 87 octane gasoline, run that. If it says E85, run that. If it says not to run premium, then don't. The people who designed the car know more than I do about what it is designed to run on.

[drolds1]

E85 is typically 105 octane. But you're comparing apples to oranges because they're two very different fuels.

 

Personally- I'm a teacher, not an engineer. I would run what the owner's manual says. If it says 87 octane gasoline, run that. If it says E85, run that. If it says not to run premium, then don't. The people who designed the car know more than I do about what it is designed to run on.

 

Although E85 has a higher octane rating than commercially available gasoline, it isn't 105 Octane:

If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanol’s blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanol’s true octane value should be used to calculate E85’s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual octane engine tests

-Changes in Gasoline Manual IV-Renewable Fuels Foundation

[drolds1]

Like bbf said, everyone has their own opinions. Personally I put 93 in my Fusion because I see a noticeable difference in the way it runs. But this is just me, not looking to tell you what to do at all. The Fusions can run on 87, however the Fusion 3.0 is also a flex fuel, and ethanol is a very high octane. I believe somewhere in the high 90's. Ethanol is not 85 octane, that only stands for 85% ethanol and 15% gasoline. I'm pretty sure this is correct. Ethanol burns hotter, and I'm almost certain the octane rating is very high. That said, it seems that this engine can take different fuels. My personal opinion, and my opinion only, I feel it runs better on premium. Best would be however, and I think we can all agree, pick a type of fuel and stick with it. Good luck! Let us know what you choose.

 

Ethanol does not burn hotter. A gallon of gasoline contains about 114,000 BTU. A gallon of E85 contains 81,800 BTU.

[Waldo]

Short story is that our engine management system is not designed for nor capable of adjusting for higher octane fuels. It simply can not take advantage of the "detonation resistance" (or other performance benefits) of higher octane fuels. Therefore, not only are you throwing money away by paying higher prices for premium, use of premium fuels may also lead to engine issues.

 

 

I don't think this is entirely accurate. The engine management systems is most certainly designed to recognize the type of fuel being used. It is certainly capable of adjusting for higher octanes. The question is how aggressive are the tables. Usually when Ford tunes an engine, they focus on one octane level. They then throw in a generic/safe adjustment for the "other" octane level but don't spend a lot of time tuning it.

 

So there is always some benefit to running premium, but usually the benefit is so small that it would never justify the increased cost of the gas. But I can't imagine running premium would ever "lead to engine issues", unless it specifically says not to use it in the manual. (note that the comment about "use of a non-recommended fuel may cause engine issues" is in the section of the manual before the octane rating, not after)

[rpreuss]

(note that the comment about "use of a non-recommended fuel may cause engine issues" is in the section of the manual before the octane rating, not after)

 

Made me get out the PDF for my hybrid. Specifically says not to use E85, diesel, methanol, leaded, etc. Only use UNLEADED (caps are theirs) or a max of 10% ethanol.

 

It only says the engine is designed for 87 octane and it is recommened to NOT use anything below 87 if you are in "a high altitude area".

 

I assume non-hybrids have similar warnings. And of course, flex-fuel engines can use E85.

 

But nowhere does it say you can not use an octane higher than 87. Just that it is designed for 87.

[bbf2530]

I don't think this is entirely accurate. The engine management systems is most certainly designed to recognize the type of fuel being used. It is certainly capable of adjusting for higher octanes. The question is how aggressive are the tables. Usually when Ford tunes an engine, they focus on one octane level. They then throw in a generic/safe adjustment for the "other" octane level but don't spend a lot of time tuning it.

 

So there is always some benefit to running premium, but usually the benefit is so small that it would never justify the increased cost of the gas. But I can't imagine running premium would ever "lead to engine issues", unless it specifically says not to use it in the manual. (note that the comment about "use of a non-recommended fuel may cause engine issues" is in the section of the manual before the octane rating, not after)

 

 

Hi Waldo. :D Awwww, come on now....not you too! :hysterical: And you are usually one of our rational voices of reason. The short version is this: If anyone can provide or refer us to one piece of literature from Ford which recommends the use of premium fuel in the current Fusion/Milan/MKZ engines, I will see the light.

 

However, until that time, on page 241 of my Owners Manual, along with a giant "87 octane" pump symbol which does not copy and paste, it clearly states “Premium unleaded gasoline is not recommended for vehicles designed to use “Regular” unleaded gasoline..." (not trying to slip anything by, the full copy and paste is below). So as can be seen, it plainly states not to run Premium fuel. The Owners Manual states to use 87 octane fuel and not to use premium once. Sheeesh, are we now like the people who dump hot McDonalds coffee in their laps? Does Ford have to put giant signs and disclaimers all over the Owners Manual and our cars stating "Don't use premium fuel"? Once should be enough.

 

We have been through this so many times in the past with other threads. The engine management system of the Fusion/Milan/MKZ is not designed to adjust to higher octanes than 87. Sure, it adjusts to octane irregularities) to a certain extent), but not to specific octane levels (as in some "premium" vehicles). Even if we were to take your statements as correct, what good is premium fuel if all Ford does is "throw in a generic/safe adjustment for the "other" octane level but don't spend a lot of time tuning it."? :redcard:

 

As Fords engine management team states, don' use premium fuel. Some engine management systems are (i.e. the 3.5L EcoBoost and usually higher end engines in other manufacturers vehicles), but currently not ours.

 

And concerning where in the paragraphs certain phrases are mentioned, as far as my Owners Manual text reads, you are incorrect. This is a direct copy and paste from my MKZ manual:

"Octane recommendations

Your vehicle is designed to use

“Regular” unleaded gasoline with pump (R+M)/2 octane rating of 87. We do not recommend the use of

gasolines labeled as “Regular” that are sold with octane ratings of 86 or lower in high altitude areas.

Do not be concerned if your engine sometimes knocks lightly. However, if it knocks heavily under most

driving conditions while you are using fuel with the recommended octane rating, see your authorized dealer to

prevent any engine damage.

Fuel quality

If you are experiencing starting, rough idle or hesitation driveability

problems, try a different brand of 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. If the problems persist, see your authorized

dealer."

 

Now, can the above wording be parsed or dissected to argue that it does not "exactly" say, "this" or "that"? Maybe in the same way that it can be stated by a certain former President "...it is all according to what the definition of is, is..." or he "...did not have sex with that woman...". :hysterical: However, in the end, the Owners Manual states that 87 octane is the recommended fuel and that premium is not recommended, and that would go for engine issues or no engine issues.

 

Debating semantics or specific word placement in paragraphs does everyone here an injustice. The fact is Ford recommends 87 octane fuel and explicitly states not to use premium fuel, as it can lead to engine issues or exacerbate already existing issues. What order they are mentioned in the Owners Manual is irrelevant.. The only mention of premium fuel is specifically not to use it.

 

Again, if anyone can provide some Ford literature stating that premium fuel is either recommended, advisable or beneficial in our cars, I will see the light.

 

Waldo, hope you understand I am not trying to be argumentative in any way. You are one of the most helpful and reasonable people on these forums. :drool: But as I have sometimes mentioned in the past, our conversations often remind me of conversations with my brother (who is an engineer). :shades: And I mean that as a complement, since like you, my brother is an extremely intelligent person.

 

Anyway, I wish you a very Merry Christmas and a Happy New Year!

 

Good luck. :beerchug:

 

PS - And my own disclaimer: If anyone still wishes to use premium because they feel it gives them a smoother running, more powerful etc. car, I say more power (no pun intended) to you, good luck and "long may you run"! It is your car (and wallet) so do what you feel is best. I am only positing the information which Ford provides for our cars. :grouphug:

Edited December 20, 2010 by bbf2530

[bbf2530]

Made me get out the PDF for my hybrid. Specifically says not to use E85, diesel, methanol, leaded, etc. Only use UNLEADED (caps are theirs) or a max of 10% ethanol.

 

It only says the engine is designed for 87 octane and it is recommened to NOT use anything below 87 if you are in "a high altitude area".

 

I assume non-hybrids have similar warnings. And of course, flex-fuel engines can use E85.

 

But nowhere does it say you can not use an octane higher than 87. Just that it is designed for 87.

 

Hi rpreuss. :D Hope all is well.

 

:grouphug: If you read a page or two further in the Hybrid Owners Manual, the exact same verbiage I copied and pasted above is there in the "Fuel Quality" section. "Premium fuel is not recommended for vehicles designed for regular fuel.... " Again, can the wording be parsed by those who feel Ford is only referring to cars with "engine issues?" Yes. However, if read in its entirety, it applies to all Ford engines in the Fusion/Milan/MKZ designed only for regular fuel (which currently is all of them).

 

So it means use the recommended fuel (87 octane) all the time. Common sense. And in the case of a vehicle which has engine/drive-ablilty issues, still don't use premium (as some owners sometimes do) to try and eliminate the issues, since the engine is not designed for it and it can even make the issues worse.

 

So we should not use premium when our engines are running well, and we should not use it when our engines are running poorly.

 

The perfect example of all of this is the EcoBoost engines: The 3.5L EcoBoost is designed to use either regular or premium and Ford clearly recommends both as a fuel source. When using premium, the EcoBoost is designed to take advantage of a premium fuels capabilities and power is increased. That is not the case with the Fusion/Milan/MKZ. The Fusion/Milan/MKZ engine is not designed to use premium, only regular. And Ford makes that clear (to most anyway) by recommending only regular and stating clearly that the engine is not designed for premium fuel. If premium was valid fuel choice, Ford would state so, as they do with the EcoBoost.

 

Again, if anyone wants to use premium go ahead, but the Owners Manual and other Ford literature is clear.

 

Good luck. :beerchug:

Edited December 20, 2010 by bbf2530

[Waldo]

Well I admit that I didn't read far enough to catch that next section.

 

However there is often a difference between the truth and what Ford prints in the owner's manual.

 

For example, the 2009 Flex (no Ecoboost available) has the identical section about fuel as what you've quoted. But in the 2010 Owner's manual, the section was revised and now reads as follows:

 

Octane recommendations

3.5L V6 engine

Your vehicle will run normally on 87 octane regular fuel. Premium fuel

will provide improved performance.

 

3.5L V6 EcoBoost engine

Your vehicle is designed to run on regular fuel with an octane rating of

87 or higher. For best overall performance, premium fuel with an octane

rating of 91 or higher is recommended. The performance gained by using

premium fuel will be most noticeable in hot weather or in severe duty

applications such as towing a trailer.

 

So the 3.5L V6, which in 2009 was not supposed to use premium fuel (per your interpretation), now gets improved performance with it. And I can tell you as a fact that absolutely nothing changed between 2009 and 2010 with regards to the engine, any of it's components or the calibration.

 

But since you admire my rationality, I will say that MY recommendation is to always use 87. I have seen test results and the "improved performance" with premium is negligible. Different story for the EcoBoost though.

[bbf2530]

Well I admit that I didn't read far enough to catch that next section.

 

However there is often a difference between the truth and what Ford prints in the owner's manual.

 

For example, the 2009 Flex (no Ecoboost available) has the identical section about fuel as what you've quoted. But in the 2010 Owner's manual, the section was revised and now reads as follows:

 

Octane recommendations

3.5L V6 engine

Your vehicle will run normally on 87 octane regular fuel. Premium fuel

will provide improved performance.

 

3.5L V6 EcoBoost engine

Your vehicle is designed to run on regular fuel with an octane rating of

87 or higher. For best overall performance, premium fuel with an octane

rating of 91 or higher is recommended. The performance gained by using

premium fuel will be most noticeable in hot weather or in severe duty

applications such as towing a trailer.

 

So the 3.5L V6, which in 2009 was not supposed to use premium fuel (per your interpretation), now gets improved performance with it. And I can tell you as a fact that absolutely nothing changed between 2009 and 2010 with regards to the engine, any of it's components or the calibration.

 

But since you admire my rationality, I will say that MY recommendation is to always use 87. I have seen test results and the "improved performance" with premium is negligible. Different story for the EcoBoost though.

 

 

Hi Waldo. :D Yes, I know what you mean (and agree) that sometimes the Owners Manuals are not updated quite expeditiously. And I will take your word for what the 2009/2010 Flex Manuals state. And we certainly agree that it is definitely a different story for the EcoBoost

 

However, the Flex manual does not apply in this case and the Fusion/Milan/MKZ Owners Manual is currently correct for the triplets (which is the vehicle the OP is inquiring about).

 

I guess my perspective is that yes, sometimes the information in an Owners Manual may be outdated or incorrect. But until it is shown/proven to be incorrect, we need to assume it is correct, not proceed under an assumption that everything is incorrect because of other unrelated errors.

 

I would compare this to the conversation with a long-since gone member here who had the very strong opinion that since he has seen mistakes in Owners Manuals in the past, no information in the Owners Manual (or anyone who quotes the Owners manual) can ever be trusted (since if the Manual has one error in it, then everything must be wrong?): Using that logic, I pointed out to him that since everyone has been wrong or made at least several (or many more) mistakes in their lives, none of us should ever believe/trust anyone or anything we ever read or hear, since if a mistake was made once, that means every single one of us can't be trusted. Of course, he was not as polite (or good-humored) as you, so he then proceeded to personally insult me and all of my past/present/future relatives. :hysterical:

 

Anyway, I guess we have provided enough information for the OP to decide what is best for him. And for the record Waldo, I admire you for many other traits than just your rationality! :grouphug:

 

Good luck. :beerchug:

Edited December 20, 2010 by bbf2530

[Oldguy16]

Can i just say this is the best conversation that has ever been posted on this forum. bbf and waldo, although i may disagree a bit, you are the first two people that actually respect a disagreement and do not attempt to start and argument. I see where you're coming from, and that is what the owner's manual states. I won't mention any names, but many people here just argue the whole time, rather than have a comprehensive debate, with proof, quotes, and personal knowledge; all of which are reasonable here. This is what a forum is supposed to be about, a conversation, attempting to quantify a question or problem. That said, here is my question now. IF the car is designed to run on E85, and that's 95 octane, why can't the car run on 93? I believe, and I don't remember where this was in the manual, but Ford does say there's about a 10hp increase with ethanol. So what I'm really asking is why would they design a car that would harm the engine on 93, but is designed to run on 87 and 95? The engine has to be able to run well on E85 otherwise there would be no purpose in making it flex fuel. Granted, ethanol is a little far from where I live, and I have not tried it myself, but do you guys understand what I mean? This is not in any means an argument started but a question.

[2010SEL]

Here is my take on it. Based on 40 or so years of being a gearhead, mechainic, automotive enthusiast, whatever: You can run a higher octane if you want to. I am quite certain you won't hurt anything inside the engine. You may or may not see an increase in power, and you may or may not be wasting your money. If the engine has knock sensors it will advance the ignition timing until it detects a knock, then back it off a little. That is great for horsepower creation and also possible mpg improvements. If the engine does not have such a knock sensing system, the engine may actually produce less power by running the high octane gas, because it burns cooler, and the engine isn't taking advantage of the octane. No simple answer. All you can really do with this new computerized stuff is try different fuels until you get the results you are looking for.

 

I am running my '10 V6 SEL on 87 octane and it runs just great. I tried 91 for a few tanks but noticed no difference in power or mpgs. At $0.20 more per gallon it made no sense to use 91.

[Waldo]

So what I'm really asking is why would they design a car that would harm the engine on 93, but is designed to run on 87 and 95?

 

E85 and gasoline are so completely different that you can't compare anything about them. The timing, fuel injection and everything is totally different for E85, regardless of the octane rating.

 

Also let's be clear, Ford didn't "design a car that would harm the engine on 93". They just put a cover-our-butts statement in the Owner's Guide.

[bbf2530]

Can i just say this is the best conversation that has ever been posted on this forum. bbf and waldo, although i may disagree a bit, you are the first two people that actually respect a disagreement and do not attempt to start and argument. I see where you're coming from, and that is what the owner's manual states. I won't mention any names, but many people here just argue the whole time, rather than have a comprehensive debate, with proof, quotes, and personal knowledge; all of which are reasonable here. This is what a forum is supposed to be about, a conversation, attempting to quantify a question or problem. That said, here is my question now. IF the car is designed to run on E85, and that's 95 octane, why can't the car run on 93? I believe, and I don't remember where this was in the manual, but Ford does say there's about a 10hp increase with ethanol. So what I'm really asking is why would they design a car that would harm the engine on 93, but is designed to run on 87 and 95? The engine has to be able to run well on E85 otherwise there would be no purpose in making it flex fuel. Granted, ethanol is a little far from where I live, and I have not tried it myself, but do you guys understand what I mean? This is not in any means an argument started but a question.

 

Hi Oldguy. :D Seasons Greetings!

 

Here is what I can tell you regarding the Flex Fuel capable Fusions (newer 3.0L V-6's): The Owners Manual has two separate "Fuel Quality' descriptions, one for "Unleaded gasoline engines" and one for "FFV engines". The "Unleaded gasoline engines" section still has the warning against using premium fuels. And although in one section the FFV engine guidelines do state "If your vehicle is flex fuel capable, it is designed to use Fuel Ethanol (Ed75–Ed85), “Regular” unleaded gasoline or any mixture of the two fuels", it does not specifically warn against using premium fuel". Here is the Flex Fuel fuel quality guidelines:

FFV engines

If you experience starting, rough idle or hesitation driveability problems during a cold start, try a different brand of E85 fuel. If the driveability

problems continue, fill the vehicle with regular unleaded gasoline and drive vehicle normally until gasoline is used. See your authorized dealer

if the problem persists. Do not add aftermarket fuel additive products to your fuel tank. It should not be necessary to add any aftermarket products to your fuel tank if you continue to use high quality fuel of the recommended octane rating. These products have not been approved for your engine and

could cause damage to the fuel system. Repairs to correct the effects of using an aftermarket product in your fuel may not be covered by your

warranty. Many of the world’s automakers approved the World-Wide Fuel Charter that recommends gasoline specifications to provide improved

performance and emission control system protection for your vehicle. Gasolines that meet the World-Wide Fuel Charter should be used when

available. Ask your fuel supplier about gasolines that meet the World-Wide Fuel Charter.

 

As can be seen, the FFV vehicles have no warnings against premium fuel. My perspective? Since the 3.0 L FFV engine has the newest engine management system of all the Fusion engines (it was updated for Flex Fuel even after the introduction of the 3.5L V-6, 2010 models I believe), it is more advanced to meet the needs of E-85. Therefore, it would have a more adaptable and wide ranging programming. This would seem to allow it to use E-85 and also would provide more adaptability for octane variation (i.e. as would be seen with premium fuels).

 

Oldguy, if you have not already taken a look at your Owners Manual, do so when you have the chance. There is also a detailed list of "caveats" concerning the use of E-85 in the FFV Fusion. It is not a free to use either, anytime, any-amount-whenever sort of situation. :shift:

 

EDIT (figured no need for a separate reply :stats: ) - Also, as Waldo stated in his last reply above: Ford did not "design a car (engine)" that would be harmed by premium fuels. First, as Waldo stated, the FFV engine is a different animal. Second, I will give a simplified explanation, but hopefully it will do: Since the engine management system of the Fusion's "regular engine" (non-FFV) is not designed to adjust for the burn characteristics/properties of premium, the additives in premium fuel can lead to inefficient burning of the fuel. {premium fuel has additional additives that help prevent premature detonation in the cylinders/combustion chamber). In an engine management system programmed to take advantage of this property, it can lead to more power production. In an engine not designed for it, it can lead to inefficient combustion, engine deposits etc.. Essentially, running premium won't "harm" anything. It will just possibly lead to some poor drive-ability, rough running etc.. All minor issues in the grand scheme of things. The only thing it will definitely hurt is your wallet. And in general practice, no added power or mpg's. Also as Waldo stated, to a certain extent it is a "cover our butts" disclaimer. :hysterical:

 

Hope this information helps.

 

Good luck. :beerchug:

Edited December 21, 2010 by bbf2530

[Waldo]

Since the engine management system of the Fusion's "regular engine" (non-FFV) is not designed to adjust for the burn characteristics/properties of premium,

 

Ahh, but there's your assumption again. Just because it doesn't say it does, doesn't mean it doesn't. The Fusion (especially the 3.5L) uses the same system as the 2011 Flex, which, according to Ford, gets "improved performance" with premium.

[Oldguy16]

This is all very good information. I have a 2010 3.0 flex fuel, and I run my car on 91 because I personally like the way it runs on 91. So concerning a 2010 with flex fuel, do you believe the engine is designed to adjust and take advantage of a higher octane fuel? I've picked this fuel and stuck with it of course, no switching around. I tried 2 tanks of 87 which I did not like the way the car ran, hence why I run 91. I'll look at the owner's manual today, but as far as the flex fuel, my guess would be that if it can take advantage of E85, it should theoretically be able to run 91 or 93 no problem. Just a guess.

[bbf2530]

Ahh, but there's your assumption again. Just because it doesn't say it does, doesn't mean it doesn't. The Fusion (especially the 3.5L) uses the same system as the 2011 Flex, which, according to Ford, gets "improved performance" with premium.

 

Hi Waldo. :D Ahhh...but your general statement above is intentionally very cloudy and does not actually answer the OP's question, it only attempts to cast doubt on my clearly labeled "perception" of what the Manual states. See how we can go on like this forever? :doh: :hysterical2:

 

No, to be honest, (in my opinion) the conversation is now getting muddled with too many variables that don't apply to the OP's (propelledjeans) original question. So we are now discussing various Fusion engines (I-4, 3.0 V-6 (earlier year non-FFV), 3.0 V-6 (present FFV), 3.5L (earlier years), 3.5L (present), various Fusion model years, and now we have injected the Flex into the conversation. And while I do not know at the moment the exact programming parameters, there are some small powertrain differences between the Fusion and Flex 3.5L models, since power output does vary very slightly (could be as simple as different intakes etc.). But in the end, it is not really important to the OP and I don't believe either of us wants to research all the variables necessary to provide solid information of that depth. :banghead:

 

In a case like this, since no one individual can cover every contingency in short Internet replies (well, relatively short anyway), we can all pick apart and parse each others replies/statements for minute detail errors. And (in my opinion) we must keep in mind the fact that until the Owners Manual information on a particular subject is proven incorrect, it should be considered correct. Can't go wrong by following the Owners Manual, since even if it has not been updated, only the possibility of a few horsepower bump in power is certainly not worth the price of premium fuel. Even the EcoBoost does not lose much when regular is used.

 

The additional problem I see now is this: Our debate of "theory, perception, assumption and small details" will only serve to confuse those who want a simple answer to the "What octane should I use..." question. As even you stated, "I will say that MY recommendation is to always use 87. I have seen test results and the "improved performance" with premium is negligible. Different story for the EcoBoost though.". So we completely agree on that subject, which is the crux of the entire discussion. The side conversation, while interesting to some, will only confuse many others who just want to know what they should use.

 

So what we can agree on is premium fuel in "most" Ford passenger car engines (non-EcoBoost) does not give a large enough power boost (if any at all) to justify the higher price. And according to the Owners Manual, the 2009-2010 Flex is at least one exception. Now, can those statements now be parsed and corrected one way or another by you or someone else? Sure, but we can do this to each other into the New Year for no apparent gain (in my opinion, of course).

 

That was why I felt since we had provided enough information to the OP that he can make an educated decision on his own, we should wish everyone a Happy Holiday and go do some more Christmas shopping for our wives. :cheerleader:

 

Merry Christmas everyone! :grouphug:

 

Good luck. :beerchug:

Edited December 21, 2010 by bbf2530

[bbf2530]

This is all very good information. I have a 2010 3.0 flex fuel, and I run my car on 91 because I personally like the way it runs on 91. So concerning a 2010 with flex fuel, do you believe the engine is designed to adjust and take advantage of a higher octane fuel? I've picked this fuel and stuck with it of course, no switching around. I tried 2 tanks of 87 which I did not like the way the car ran, hence why I run 91. I'll look at the owner's manual today, but as far as the flex fuel, my guess would be that if it can take advantage of E85, it should theoretically be able to run 91 or 93 no problem. Just a guess.

 

Hi Oldguy. :D My opinion? If you are happier with 91 octane, continue to use it.

 

If you would like to save some money when you fill up, try another (major name) brand of 87 octane regular. Since our vehicles are designed to run on 87 octane, a good quality 87 octane should cause no issues. Perhaps you got a tank or two of bad gas when you filled with regular. I can tell you that I have used regular fuel (again, only major oil company brands) for over 4 years in my 2007 MKZ and never had an issue. :shift:

 

But in the end, what makes you happy is what matters. So if you feel more comfortable with 91 octane, then use it. If you feel any drive-ability issues over the long run (they would usually only occur over the long run, if at all) then think about switching back to regular for a while. :shift:

 

In reality, it all comes down to the "perceived" benefit versus cost ratio for premium fuel.

 

Or alternately, if you wish to delve deeper, call Ford's Customer Satisfaction number and ask to be put in contact with someone from the engine management team. Ask them what you should do. Beats listening to us Internet mooks jabber on and on! :hysterical: Only kidding Waldo! :grouphug:

 

Merry Christmas and good luck! :beerchug:

Edited December 22, 2010 by bbf2530

[jtb3]

Hey everyone.

 

Just got a 2010 Fusion yesterday (woo!) and was curious about which gas to put in it. I've done some searching on the forums and read that "93 hurts the car" or "93 is better for the car" or "just put 87" etc.

 

Which should I believe? Which do you recommend?

 

Thanks in advance,

 

James

 

Wow man, I thought this was a very easy question to answer........but you sure opened a "can of worms"!!!

[tsetse51]

There's still a lot of confusion about just what the octane rating means. Simply put: Octane is a measure of a fuel's ability to resist detonation (spontaneous combustion, without a spark) when pressure and heat are applied. Higher-octane gasoline actually burns more slowly than lower-octane gasoline, because it's not as volatile. The use of higher-octane fuel, by itself, does NOT increase the power available. It does allow higher compression pressures to be used, without engine damage from detonation. Higher compression ratios, turbo boost, etc. then can safely be used to increase power output.

 

Modern electronically-controlled engines can make use of fuel with a LOWER than recommended octane rating, by adjusting spark and fuel injection parameters, to some extent. The engine may run satisfactorily under these conditions, but it will not make its full rated power output.

 

Use of fuel with a higher-than-recommended octane rating MAY not cause any problems. It also MAY cause excessive carbon formation in combustion chambers, spark plug fouling or deposits, etc. The best fuel for any gasoline engine is the one with the lowest octane rating specified by the engine maker. It should also NOT be simply the cheapest you can find, from a questionable supplier.

Edited December 22, 2010 by tsetse51