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Discussion Starter #1
the specs for the ST(at least in Canada) say that premium fuel is recommended. Does that mean that it is required?
What would the consequences be of using regular fuel. The ecoboost engine in the Escape requires only regular fuel
and is rated at 240 HP. If that is the only difference, then it is not significant.
gary
 

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You'll lose performance and mileage, but you can use it.

I am completely ignorant to the Canadian octane situation, so forgive me if your options aren't plentiful. But here, there is absolutely no reason not to use premium fuel at all times in almost any city, town, or municipality. You can get premium at nearly every pump and should use it on almost any modern vehicle, and certainly any high-compression motor or anything that says it is recommended.

The cost savings for using even the lowest available octane here vs. the highest are so marginal and negligible that it isn't even worth pondering using the lower octane stuff.
 

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Not going to get in a debate about what you should use. But use what's recommended. If there is no recommendation use the lowest AKI fuel available.
 

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I've already scouted my local gas stations and have found 2 that sell 93 octane


On the go - Via TapTalk
 

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The Owners Manual Supplemnt was great reading and great resource for potential buyers. Now I know what size snow tires to get!
 

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Most of the stations around me have 93 octane which is what I run in the Mustang. I will probably run 93 in the ST has well, while maybe dropping down to 87 in the winter.
 

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Most of the stations around me have 93 octane which is what I run in the Mustang. I will probably run 93 in the ST has well, while maybe dropping down to 87 in the winter.
What's the theory there? I don't really know what snow looks like outside of a vacation situation, keep in mind.
 

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Where I live most gas stations have 87, 89, 91octane.

Select Petro's sell 94 as well. You think that extra octane will be good for 255hp:D
 

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What's the theory there? I don't really know what snow looks like outside of a vacation situation, keep in mind.
Nothing really specific, I figure in the winter I'm not going to need the extra 10hp the higher octane gives me so why pay extra for it in the winter, a Friend has told me to just run 93 year round which I may do but I'm not entirely sold on the idea yet. He's got a Golf R and that's what he's planning on doing.
 

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Nothing really specific, I figure in the winter I'm not going to need the extra 10hp the higher octane gives me so why pay extra for it in the winter, a Friend has told me to just run 93 year round which I may do but I'm not entirely sold on the idea yet. He's got a Golf R and that's what he's planning on doing.
Winter blends of gasoline will drop your fuel economy more....I would stick with 93 octane year-round if you are interested in saving $$$.
 

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Winter = cooler air = denser air = higher static pressure which requires higher octane, FWIW. If you're not beating the car (WOT/open loop), it won't matter what octane you use, the timing always adjusts for optimum burn when cruising. You may see a very slight change in fuel economy, but cold temps will lower that regardless of octane used because of the denser air.
 

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Winter blends of gasoline will drop your fuel economy more....I would stick with 93 octane year-round if you are interested in saving $$$.
Well that's why I'm going to try it out. I run 93 on the Mustang and get about 27mpg on the highway, I don't know how much the 93 octane is helping. I figure I'll try out 93 and see what the mpg ends up being and then run a few tanks of 87 to see how it compares and stick with whichever is best. My economy is on my Current Focus usually drops from about 36-37mpg on the highway to around 33mpg during the winter while running 87.
 

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Winter = cooler air = denser air = higher static pressure which requires higher octane, FWIW. If you're not beating the car (WOT/open loop), it won't matter what octane you use, the timing always adjusts for optimum burn when cruising. You may see a very slight change in fuel economy, but cold temps will lower that regardless of octane used because of the denser air.
Exactly what I figured, since I won't be beating on it during the winter as much I might as well save the 20-30cents a gallon.
 

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A few comments regarding this thread:

1. The cooler winter air reduces the demand for octane because detonation is less likely with cooler air. The fact that the air is denser in winter requires more fuel for the proper mixture but does not increase the demand for octane. Atmospheric pressure varies all through the year you can have higher pressure in the summer than the winter at times. In theory you can run lower octane in the winter with no loss of power or economy. It's the summer that the need for more octane occurs.

2. Back in the 70's when the EPA forced the reformulation of gas it was to make it less volatile so it wouldn't evaporate into the atmosphere as fast. The first winter with the reformulated gas folks had all kinds of trouble starting their cars in the cold climates. The EPA allowed the gas to go be formulated to be more volatile in the winter. So the gas you get in the winter is closer to what it was before the EPA stepped in.

3. The octane of the fuel is just a measure of its resistance to uncontrolled and spontaneous burning. It has no baring on how much potential energy is in the fuel. By it self you will not make more power with higher octane.

4. The systems in cars have no way of knowing what the octane of the fuel in the tank is. The engineers design/tune the engine to operate on a given fuel and tune it close to the edge then allow the knock sensor to tell the computer to detune when detonation is detected. Running higher than recommended octane will not give you more power. It can help maintain the power at its highest by preventing detuning by the knock sensor.

5. Just adding timing and increasing the octane to go with it doesn't mean more power. There is a sweet spot on the combustion stroke where the most power will be made. For that to happen the fuel needs to be ignited early enough so maximum cylinder pressure occurs at the sweet spot. To little timing and max pressure occurs after the sweet spot and you don't get max power. To much timing an max pressure occurs before the sweet spot and you don't get max power.

Back in the muscle car area you would get detonation before you could have enough timing to hit the sweet spot and it was from that era that adding timing and increasing octane meant more power. These days with computer control, better cylinder head chamber design and direct injection the timing is very close to where it needs to be.
 

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A few comments regarding this thread:

1. The cooler winter air reduces the demand for octane because detonation is less likely with cooler air. The fact that the air is denser in winter requires more fuel for the proper mixture but does not increase the demand for octane. Atmospheric pressure varies all through the year you can have higher pressure in the summer than the winter at times. In theory you can run lower octane in the winter with no loss of power or economy. It's the summer that the need for more octane occurs.

2. Back in the 70's when the EPA forced the reformulation of gas it was to make it less volatile so it wouldn't evaporate into the atmosphere as fast. The first winter with the reformulated gas folks had all kinds of trouble starting their cars in the cold climates. The EPA allowed the gas to go be formulated to be more volatile in the winter. So the gas you get in the winter is closer to what it was before the EPA stepped in.

3. The octane of the fuel is just a measure of its resistance to uncontrolled and spontaneous burning. It has no baring on how much potential energy is in the fuel. By it self you will not make more power with higher octane.

4. The systems in cars have no way of knowing what the octane of the fuel in the tank is. The engineers design/tune the engine to operate on a given fuel and tune it close to the edge then allow the knock sensor to tell the computer to detune when detonation is detected. Running higher than recommended octane will not give you more power. It can help maintain the power at its highest by preventing detuning by the knock sensor.

5. Just adding timing and increasing the octane to go with it doesn't mean more power. There is a sweet spot on the combustion stroke where the most power will be made. For that to happen the fuel needs to be ignited early enough so maximum cylinder pressure occurs at the sweet spot. To little timing and max pressure occurs after the sweet spot and you don't get max power. To much timing an max pressure occurs before the sweet spot and you don't get max power.

Back in the muscle car area you would get detonation before you could have enough timing to hit the sweet spot and it was from that era that adding timing and increasing octane meant more power. These days with computer control, better cylinder head chamber design and direct injection the timing is very close to where it needs to be.
The last sentence couldn't be more wrong as its a general blanket statement. Timing on modern cars is decently advanced but on pretty much all cars especially turbo cars...the fuel is the limiting factor. High compression, turbos, make for an efficient engine but it stresses pump gas a lot. Dump in race gas, ethanol and the fun can really begin, and you can actually reach mbt.
 
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