POLL: Will 85 Octane Ruin The Bronco?

[thepear]

Hey Everyone,

I wanted to bring up the idea about using 85 octane in the Bronco vs 87. Since I live in a high altitude city the basic fuel is 85 and midrange is 87. Since getting the Bronco I have been putting in 87 but was wondering if playing the extra 30 cents a gallon was saving the car or just burning it away. I looked around and heard augments from both sides stating that 85 is identical to 87 in higher climates and you shouldn't worry. I also heard that I should stick to what the owners manual states and follow that. I checked the manual and there is nothing that I could find about 85 octane and states to use a minimum of 87. Even the fuel door states 87+ with a sticker.

I don't think I have ever seen an owners manual bring up the idea of substituting 85 octane when above XXXX altitude. Anyone out here putting 85 octane in their Bronco and if so have you noticed any adverse effects?

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[Aonarch]

RTM

87+ octane required.

85 octane is left over from the carb days.

 

[BlueWaffle]

85 would be fine if it were N/A.. Definitely wouldn't run it in a turbo.

 

[Fordified1]

85 would be fine if it were N/A.. Definitely wouldn't run it in a turbo.

Exactly. The turbo forces in the atmosphere that a N/A engine can not get at high altitude (thin atmosphere), so is still subject to spark knock with low octane fuel even at high altitudes.

 

[Headsong]

A poll? Like winning the poll establishes truth?

 

[dadjoke]

RTM

87+ octane required.

85 octane is left over from the carb days.

This is where I landed too...EFI exists to overcome problems of carburetors. While I don't suspect that running 85 for a short time would be a catastrophe, I don't know that it's a long term solution.

FAAFO? lol Best of luck, regardless!

 

[CarmeloS]

What the fuck is 85???

 

[ScLeCo]

 

[TheShark]

I'm assuming you mean E85 otherwise known as Flex Fuel?

 

[ScLeCo]

A poll? Like winning the poll establishes truth?

 

[cbrenthus]

It won't ruin the Bronco, only the engine


But cheaping out on Octane has always amazed me, especially with nice cars. Let's say you fill up once a week - $0.30 per gallon at 20 gallons is $6 per fill up, 52 weeks in the year means you'll pay $312 a year to put the proper gasoline in your vehicle. How much do we spend a year on payments, insurance, and accessories? And we're going to try to save a few hundred on the lifeblood of the vehicle?

I have the V6 and run 93 only - I didn't pay for the V6 to not get peak performance.

 

[Aonarch]

I'm assuming you mean E85 otherwise known as Flex Fuel?

No, 85 octane. It is common out west. Every station here has it.

 

[beetle]

91+ only.

 

[KABQ]

I'm assuming you mean E85 otherwise known as Flex Fuel?

86 basically isn't a thing out here. 85 is the standard at altitude out west (NM, CO, UT, WY, MT, etc). No 93 tunes for us, the highest octane I can find on a regular basis is 91.

 

[RagnarKon]

As others have said, what worked previously with carbureted or naturally aspirated engines doesn't work on engines with turbos. And both of the Bronco's engines have turbos.

Octane rating signifies the fuel's resistance to pre-mature detonation. At high altitudes, the air is less dense, which means less oxygen in the air, which means it naturally is more resistant to detonation than air at lower altitudes. But if you have a turbo compressing the air, none of that is valid.

In theory... the knock sensors should save the engine from destruction. But I wouldn't make a habit of it and generally wouldn't try it outside of emergencies.

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