Noob octane error - filled 1/2 tank w/85 octane

[D Fresh]

take note: better performance under certain circumstances. general driving you're wasting your money.
but there are some claims out there that premium nets you extra horsepower and some guys will stand on their head and wiggle their toes to prove it.
but its hogwash. (the tuner marketing dyno charts will arrive shortly)

as far as engine longevity, perhaps the higher tier fuel will reduce your intake valve deposits...that's it.
the same guys dance on their heads to say other foolish things about how their engine becomes some platinum plated internal combustion wonder by over spending on a fuel they don't require.

Yes, some need 91 or 93....but not everyone needs it to run their truck into the ground thousands of miles from now.

to each their own. I like to spend my money on hard drugs and hookers. they like to burn theirs.

Why do you refuse to believe this? It is well known that Ford Ecoboost motors use the OAR to adjust timing as needed. Anybody whose ever once tuned an ecoboost can attest to it.

Just Google Ford Ecoboost OAR if you must go down the rabbit hole yourself.

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[Dgc333]

This might answer my question…. I just posted it. Would this need to be added to 90 octane or could you get away with 87 octane and then boosting with this product?

The local auto store type of octane booster does not do much. When they say it raises the octane 5 points they mean .5 of an octane.

There are octane boosters that will raise the octane multiple full points but you will need to get it on line or at a speed shop.

 

[Langwilliams]

Are some mixing up E85 which is 15% gas an 85% ethanol with regular gas rated at 85 octane?

Which did the OP use? E85 could be bad. It takes more fuel to make the same power so there could be some problems from it.

 

[VAMike]

Thanks... I saw that, but it didn't say anything about engine longevity with higher octane (as others in this thread were implying). I can, of course, see that higher octane is better performance.
What about engine life though, as others had eluded to in this thread?

Modern engines have knock detectors and adjust the timing & boost to compensate for preignition. There's a limit to how far they can/will adjust, and the language "designed to run on...gasoline with a minimum pump octane rating of 87" kinda suggests where that limit is. If the engine does knock it will eventually tear up the cylinder walls & pistons, maybe kill the crankshaft bearings. Now, engines are typically designed with a safety margin and you probably aren't going to destroy your engine running a bit of 85 octane through it. But what is the safety margin and what can you get away with before causing damage? ?‍ Ford knows, but they aren't going to tell you more than "minimum pump octane rating of 87". Pushing the limit to save a couple of bucks with gas manufacturer specifically says not to use seems crazy to me, but to each his own.

Edit to add: picture of the little craters burned into a piston when there are uncontrolled explosions in the cylinder https://www.researchgate.net/figure/Damaged-piston-examples-from-heavy-engine-knock_fig6_282849935

 

[NOVA_Ranger]

Just avoid hole shots from stop lights and anything else that could cause detonation issues. With 'normal' driving the truck should manage everything from there to avoid any issues. If you were running a 93 tune and filled it with low octane fuel it might be worth worrying about, but I wouldn't stress about it if it were my truck.

 

[jflogerzi]

Was the handle yellow? Was this e85. I was not even aware they made gas below 87 octane in the states...

But if this was e85 I would drain the tank of gas.

 

[CHS]

It will be fine, just drive to 1/2 then top it with 91 and you're good. I had a buddy that put Diesel in his Harley on a trip, at least he noticed before we left. Delayed the trip until we emptied and flushed the tank and drained the lines.

I did the same thing with my Honda Goldwing. Was at a BP station that uses the green handle for diesel unlike other that use it for regular gas. I noticed when I already had roughly 4 gallons in the tank. the station had a manual pump and I bought a couple 1 gallon cans. Sucked it out, put a gallon back in and sucked that out. Then I filled the tank with regular fuel. All OK. Funny thing is that the engine was knocking when going up hills, but after the mishap it stopped for a few days.

 

[jsphlynch]

I did the same thing with my Honda Goldwing. Was at a BP station that uses the green handle for diesel unlike other that use it for regular gas. I noticed when I already had roughly 4 gallons in the tank. the station had a manual pump and I bought a couple 1 gallon cans. Sucked it out, put a gallon back in and sucked that out. Then I filled the tank with regular fuel. All OK. Funny thing is that the engine was knocking when going up hills, but after the mishap it stopped for a few days.

I did basically the opposite the first time I filled up at a BP with their normal handle color scheme. I pulled up to the first open pump, shut off my pickup, and hopped out to only see a green handle at that pump, which is something I had only previously seen for diesel. Got back in my pickup, pulled up to another pump, but saw that one also only had a green handle. I decided I must be at the wrong bank of pumps and pulled around to the other bank, to once again find only a green handle. Suddenly I realized that the pump had the row of buttons for selecting gasoline grade, and that's when it finally clicked that green didn't mean diesel here. I can only imagine what the gas station attendant was thinking watching me drive around to each of his pumps before finally choosing one.

 

[D Fresh]

Thanks... I saw that, but it didn't say anything about engine longevity with higher octane (as others in this thread were implying). I can, of course, see that higher octane is better performance.
What about engine life though, as others had eluded to in this thread?

The reasons behind my madness, only running premium in my EcoBoost motors is two fold. But to see both points you really need to understand knock/preignition, compression ratios, octane ratings, and Ford's EMS.

Knock and preignition are basically fuel igniting before spark is applied, due to compression alone, this can happen due to high compression ratios, poor timing of the engine, or too lean of fuel mixture. High compression ratios are necessary to facilitate performance. While an engine designed to be boosted will have a relatively low static compression ratio, under full boost they can be very high. Our motor is 9.5:1 static and at full boost (15psi?) the effective compression ratio can jump upwards of 16:1. Octane is simply a fuel's resistance to preignition and knock.

The Ford engine management uses OAR, octane adjust ratio to advance or retard timing due to the lack of, or presence of knock. Feeding your truck the highest quality fuel will keep knock to a minimum, allowing the engine management system to advance timing as much as possible, thus increasing performance.

On the flip side, it will retard timing if any knock events are detected. Theoritically protecting the engine from lower octane fuels. However, in order to do that, it first has to detect something. It adjusts very quickly, but I'm of the mind that I'd rather it not happen at all. Any knock events are inherently bad for your engine.

This is why some of us run premium both for the performance, and engine longevity.

Are some mixing up E85 which is 15% gas an 85% ethanol with regular gas rated at 85 octane?

Which did the OP use? E85 could be bad. It takes more fuel to make the same power so there could be some problems from it.

He said 85, not e85. I'm gonna ASSUME he meant 85 unleaded.

Was the handle yellow? Was this e85. I was not even aware they made gas below 87 octane in the states...

But if this was e85 I would drain the tank of gas.

Everywhere west of the Mississippi, that's above maybe 3000ft sells 85 unleaded as regular instead of 87.

I did basically the opposite the first time I filled up at a BP with their normal handle color scheme. I pulled up to the first open pump, shut off my pickup, and hopped out to only see a green handle at that pump, which is something I had only previously seen for diesel. Got back in my pickup, pulled up to another pump, but saw that one also only had a green handle. I decided I must be at the wrong bank of pumps and pulled around to the other bank, to once again find only a green handle. Suddenly I realized that the pump had the row of buttons for selecting gasoline grade, and that's when it finally clicked that green didn't mean diesel here. I can only imagine what the gas station attendant was thinking watching me drive around to each of his pumps before finally choosing one.

"Why did these asshats make all their handles green?"

 

[P. A. Schilke]

I did basically the opposite the first time I filled up at a BP with their normal handle color scheme. I pulled up to the first open pump, shut off my pickup, and hopped out to only see a green handle at that pump, which is something I had only previously seen for diesel. Got back in my pickup, pulled up to another pump, but saw that one also only had a green handle. I decided I must be at the wrong bank of pumps and pulled around to the other bank, to once again find only a green handle. Suddenly I realized that the pump had the row of buttons for selecting gasoline grade, and that's when it finally clicked that green didn't mean diesel here. I can only imagine what the gas station attendant was thinking watching me drive around to each of his pumps before finally choosing one.

Hi Joe,

Yep...the Green hose/handle has tricked a couple RVers with diesel pushers. One fellow in particular was running low and filled up with 130 gallons of unleaded into his 150 gallon diesel tank...It was quite a mess and costly to get the fuel pumped out of the tank...

best,
Phil

 

[Apples]

If you want to start having really big issues, dump a can of octane booster (104® Octane Boost et. al.) in the gas tank! Most are formulations of methylcyclopentadienyl manganese tricarbonyl (MMT), and will cause premature spark plug failure. The same can be said for methyl tert-butyl ether (MTBE). Both compounds are covered under EPA rules, and their use is limited to less than .5%. And... If you read the fine print in the owner's manual, their use voids the warranty! Fore warned, fore armed!

 

[jthompson48]

FWIW, while living in CO I put probably 7500 miles of exclusively 85 on my 2019 Ranger before I realized that's not recommended. I switched to 87 just to be careful but it didn't change anything about the vehicle that I could discern. That being said, since trading in for a 2021 I only use 87+. I've noticed that in western KS, 86 octane is an option!

 

[Utope]

My wife did that when she drove the truck the first time. Luckily there was close to a half tank of 91 in it. I figured it was close to 87 mixed. I just didn’t get on it until I could add another half tank of 91. Then I ran that tank empty before the next fill.

So I’d recommend the same, fill up again with 91 after you use a quarter or half tank.

 

[Wytchdctr]

My Cobalt SS stock called for 91+ only; with a warning on the cap itself. In the user manual, it gave the procedures that others have given in this thread if you are forced to run lower octane. Keep it out of boost, do not add an octane booster, and burn it off as soon as possible with slow/calm driving. It was GM logic but seems applicable here - except the octane in the tank isn't that far off what it is tuned for anyway and the knock sensors are probably a bit better on the EcoBoost vs the 2009 half saab I had a few years back.

 

[NOVA_Ranger]

Was the handle yellow? Was this e85. I was not even aware they made gas below 87 octane in the states...

But if this was e85 I would drain the tank of gas.

Now THAT is another issue, haha. I didn't even consider that possibility.

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