87 octane vs 93 octane - ECOBOOST

[SALEEN961]

It's also worth mentioning that the laboratory test report states that the 2017 3.5EB F150 was rated at 375 hp @ 5,000 rpm and 470 lb-ft @ 3,500 rpm on 87 octane, regular fuel.

This means that when the laboratory testing suggested that "the engine torque is increased with the higher octane fuel due to spark advance ", is it also suggesting that the engine torque and horsepower is increased above and beyond the advertised power rating that Ford gave that engine on 87 octane fuel. 87 octane fuel is the minimum requirement to achieve the advertised horsepower and torque for the 2017 3.5EB F150.

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[wayfarer556]

I end up having to do homework for these posts... that's OK since I learn something each time. But in the end you guys think that the computer controls can override basic thermodynamice, chemistry, & Mechanical Engineering. That's just false. You're spinning fanciful theories that are just wrong. Have a nice day out there, I've had enough trying to teach these fundamentals.

LIterally no one here thinks that.

The computer monitors engine condition and the fuel that it's burning. It makes adjustments to compensate. One of those factors that leads to the adjustments is the kind of fuel it senses is being burned.
Those adjustments come from a place of safety. Ford isn't selling trucks that are tuned to the bleeding edge limit, they are intentionally leaving a lot of performance on the table in the interest of longevity. Within that large margin of error, the computer can make adjustments on the fly. This is not a technique unique to Ford.

Honestly this is pretty obvious to everyone on the thread. It's only you who's apparently having a temper tantrum that no one is taking you at your word. It's clear to me, a layman, that there's a lot of good knowledge in this thread and there are cooler heads who don't react like a child whenever someone contradicts their knowledge. I tend to listen to those people more.

 

[Longdeck]

Enjoyable reading and throughly entertained reading different opinions on this subject

Don’t let feelings overcome common sense, even if little to be had.

 

[dogboye]

Well, I know I certainly learned a lot from this thread. I started out thinking the same thing that Gros Venture did, but I see that, similarly to my discussion with @Snakebitten in another thread, I was not considering enough of the variables that come into play with modern, computer controlled engines, that have so many variables to play with.
So, one more question, though. Towing a horse trailer... towing through eastern mountains (Front Royal VA area), considering 87 vs. 93 octane: If I'm not concerned with extracting maximum performance from the engine, the engine will still operate better, and is not working as hard (detriment to longevity) if I run 93 octane instead of 87. Correct?

For general use, I can't see paying the extra cost of 93 octane, since other than towing that trailer, we are really NEVER trying to extract maximum performance from the engine. Without knowing specifically the increased mileage that may be possible from 93 octane, and factoring in the constantly varying cost of 93 octane, I have the feeling (based on no facts, just speculation) that the increase in mileage will not offset the increase in per-gallon cost of 93 octane.

 

[JExpedition07]

87 octane will not damage your engine. That’s what the knock sensors are there for, they will retard ignition timing to prevent pre-ignition of the fuel. You just lose some power, but no danger to longevity. 87 vs 93 won’t have any effect on reliability.

 

[SALEEN961]

...So, one more question, though. Towing a horse trailer... towing through eastern mountains (Front Royal VA area), considering 87 vs. 93 octane: If I'm not concerned with extracting maximum performance from the engine, the engine will still operate better, and is not working as hard (detriment to longevity) if I run 93 octane instead of 87. Correct?...

I wouldn't be concerned about engine failure while running 87oct, but if you are climbing steep grades for extended periods of time while towing you will see very high EGTs. Running 93oct will help to keep your EGTs lower and will also help to prevent overheating.

Avoiding excessively high EGTs should extend exhaust manifold and turbocharger life, but climbing a steep grade every now and then with 87oct shouldn't cause either to fail in the near future.

 

[Snakebitten]

For the folks that would consider anything Ford puts into writing as indisputable, Ford recommends premium when towing right there in the owner's manual. I'm just saying.

I doubt that's to improve 0-60mph numbers.

 

[SilverPigeon]

Wether it's on the 5.0 discussion, or on this one, I see the same end result: for me, it's insurance.
- we have expensive trucks
- engine management can only protect the engine to a point where it can no longer take the measures necessary to protect from detonation. Where is this actual limit? We don't know. This leads to:
- can we be sure that what we are putting in the tank is actually 87? What if it's 83 and 15% ethanol, selling as 87, but it's been sitting in the half-empty underground tank for a month because it's an out-of-the-way gas station that gets a fill of the "chocolate milk" gas every couple of months?

unlike e85 test kits, we don't test our pump gas, do we? At least with 93 (my 98RON) I've a little more room for protection, a thicker prophylactic if you will

 

[WhiteLightningnshitshadow]

So question

If:

• timing is constantly changing to avoid knock
• 87 (in CO-midgrade) is just a mixture of 85 "reg" and 91 "prem"
• Costco doesn't offer anything but 85 (3.67$ gal) and 91 (4.20$ gal)

am I possibly doing damage by filling my 36 gal tank with 91, then when it gets to about 5/8s full, adding 85, the alternating fill ups whenever I reach that 5/8ths tank level? Is that constant adjustment bad? I never really go below half a tank in any vehicle.

 

[SilverPigeon]

So question

If:

• timing is constantly changing to avoid knock
• 87 (in CO-midgrade) is just a mixture of 85 "reg" and 91 "prem"
• Costco doesn't offer anything but 85 (3.67$ gal) and 91 (4.20$ gal)

am I possibly doing damage by filling my 36 gal tank with 91, then when it gets to about 5/8s full, adding 85, the alternating fill ups whenever I reach that 5/8ths tank level? Is that constant adjustment bad? I never really go below half a tank in any vehicle.

Probably not doing damage. Even ford say in the manual that a little knock isn't an issue... but they also say to ideally decide to stick to one octane so that the system doesn't Have to re-learn so much. one must remember though, the EcoBoosts aren't flex fuel, so there is an upper limit to the ethanol %. Probably more to do with damage to the fuel system (pump, lines) than the engine. I don't know the limit, 10%? 15%? It's not E85 without serious mods for EcoBoosts I think.

 

[JExpedition07]

The EcoBoost lines are safe with E-85, its stock fuel pump and injectors aren’t capable of providing the volume needed for ethanol is the factor there. The 5.0 fuel pump and injectors are flex fuel capable from the factory so they can deliver the required volume. People do run EcoBoosts on ethanol, but you need to make revisions to the fuel system in order to do so.

 

[joejamesatou]

You can mix that 91/85. I just die a little inside whenever someone puts an 85 octane nozzle in their truck.

 

[JExpedition07]

The 5.0 cannot handle 85 octane, that’s below even what the knock sensors can protect you from. There are limits. Not sure on the EcoBoost, but I think up in boost you’d have the same issue. Lots of guys get severe pinging on 85 octane on the forums with the V8.

 

[wayfarer556]

So question

If:

• timing is constantly changing to avoid knock
• 87 (in CO-midgrade) is just a mixture of 85 "reg" and 91 "prem"
• Costco doesn't offer anything but 85 (3.67$ gal) and 91 (4.20$ gal)

am I possibly doing damage by filling my 36 gal tank with 91, then when it gets to about 5/8s full, adding 85, the alternating fill ups whenever I reach that 5/8ths tank level? Is that constant adjustment bad? I never really go below half a tank in any vehicle.

Assuming you have a 36 gallon tank, the difference per tank is about $13. Personally I'm willing to pay that difference to not have to worry about it.

 

[wayfarer556]

87 octane will not damage your engine. That’s what the knock sensors are there for, they will retard ignition timing to prevent pre-ignition of the fuel. You just lose some power, but no danger to longevity. 87 vs 93 won’t have any effect on reliability.

Honestly over the lifetime of a vehicle I figure why push it? Lots of other variables at play here including outside temperatures (it's not just hot, it's currently fucking hot), engine wear, etc. It's a few bucks more per tank. If I wanted to squeeze dollars over gas I would be driving a Camry.

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