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Discussion Starter · #1 ·
Having never owned a vehicle that requires premium fuel before, how important is using premium in the Fiesta ST.

The brochure says that premium is recommended for ecoboost. The Ford sales guy told me that that using regular is fine for the engine, and you'll only lose out on about 7% of the boost power. Does anyone know if this is true or not? Will using regular fuel damage the engine over time?

Thanks
 

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No I don't think it will, but why not use the couple of cents to make sure you get the most performance from the car and maybe a little better mileage.
 

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Sales guy is right (for once!) - the computer can run the engine on 87 just fine. I'm seeing between 1-2 mpg difference between 87 and 93. may not be worth the extra money for 93 if you're just commuting
 

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Discussion Starter · #4 ·
Thanks guys. With the gas prices in Canada switching from regular to premium costs an extra $8 a tank, which doesn't seem like much but I commute pretty far for work, so my idea was to use the regular fuel for commutes. I bought this car and hope to drive it till it dies, so my biggest concern is just that the engine won't be damaged using regular fuel.
 

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If the Regular fuel is unleaded, it will be fine, but rather pay that bit extra and get the best and highest octane rating fuel you can find.
 

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The difference between regular and 91/93/94 would be that the higher octane burns more efficiently and your car will feel more lively. You probably should use premium because lets face it...if you cannot afford the $8 a tank you probably shouldn't have bought the car.

Also regular fuel uses 10% Ethanol which is actually corrosive. There is a big push right now from governments for E15 (15% Ethanol) which would be even worse. All new cars are fine but in my honest opinion, stay away from Ethanol if you can.
 

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The difference between regular and 91/93/94 would be that the higher octane burns more efficiently and your car will feel more lively. You probably should use premium because lets face it...if you cannot afford the $8 a tank you probably shouldn't have bought the car.

Also regular fuel uses 10% Ethanol which is actually corrosive. There is a big push right now from governments for E15 (15% Ethanol) which would be even worse. All new cars are fine but in my honest opinion, stay away from Ethanol if you can.
Depends on the area I'm sure, but here in GA, all octanes, 'may have up to 10% ethanol', according to the mandatory sticker at every pump that sells it.
 

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Depends on the area I'm sure, but here in GA, all octanes, 'may have up to 10% ethanol', according to the mandatory sticker at every pump that sells it.
In Canada, Shell doesn't have ethanol in their 91oct. Petro Canada has 10% in their 94oct and Esso I believe doesn't use ethanol in their 91oct.

It seems to be hit and miss where you are in the US. I am a sales rep and am in California and Texas a lot. California has BRUTAL fuel compared to Canada.
 

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1. using regular for this particular car will not cause any damage. The ECU safely makes up for the lower octane to make sure the engine is operating safely.
2. Ethanol is in every grade of fuel and actually increases the octane rating (look it up). Our cars are made from the factory to safely handle up to 15% ethanol in the gasoline. Filling up with any grade of gas gives you the same 10% ethanol, so that argument is moot (plus OP is in Canada, so they actually have a choice over there)
3. If you put lots of miles on your car, and there is no noticeable loss in fuel consumption, the savings add up quickly. I wouldn't look down on someone if they drive a lot and want to save a significant amount of money using regular. One can always fill up with 93 prior to a trip to the winding road country, but if you live in NYC, your twisties are the on and off ramps filled with potholes.
 

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Having never owned a vehicle that requires premium fuel before, how important is using premium in the Fiesta ST.

The brochure says that premium is recommended for ecoboost. The Ford sales guy told me that that using regular is fine for the engine, and you'll only lose out on about 7% of the boost power. Does anyone know if this is true or not? Will using regular fuel damage the engine over time?

Thanks
Understand fuel and you can make your best choice. Premium fuel has no power adding benefit. But it allows the engine to make changes that make more power. Premium fuel burns at a slower rate so the computer can advance timing which increases power. The additives are the same at a gas station weather you use 87 or 93.
 

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HOWEVER: if you plan to EVER re-map the engine (Accessport V III e.g.) you WILL have to chose to use 91 or 93 and stick with it!
 

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Having never owned a vehicle that requires premium fuel before, how important is using premium in the Fiesta ST.

The brochure says that premium is recommended for ecoboost. The Ford sales guy told me that that using regular is fine for the engine, and you'll only lose out on about 7% of the boost power. Does anyone know if this is true or not? Will using regular fuel damage the engine over time?

Thanks
Really the difference between a tank of regular and premium is MAX $7-8. If you aren't willing to take that "hit", maybe this isn't the car for you.
 

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Really the difference between a tank of regular and premium is MAX $7-8. If you aren't willing to take that "hit", maybe this isn't the car for you.
I disagree. There are no 'rules' as to what car people should drive. If the OP wants to run 87, the car can handle it and was designed to. While it isn't the fuel I would prefer to run on my commute, it definitely makes sense to save the money during the week of a long steady-state commute and then fill up with premium for some performance driving.


Full-disclosure: I won't run anything but Shell 93 V-Power. Personal preference.
 

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I disagree. There are no 'rules' as to what car people should drive. If the OP wants to run 87, the car can handle it and was designed to. While it isn't the fuel I would prefer to run on my commute, it definitely makes sense to save the money during the week of a long steady-state commute and then fill up with premium for some performance driving.


Full-disclosure: I won't run anything but Shell 93 V-Power. Personal preference.
On the other hand though, if you feel like you are wasting that money...look elsewhere. Most people spend WAY more than that on coffee or eating out for lunch meantime between fill ups.
 

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The difference between regular and 91/93/94 would be that the higher octane burns more efficiently and your car will feel more lively. You probably should use premium because lets face it...if you cannot afford the $8 a tank you probably shouldn't have bought the car.

Also regular fuel uses 10% Ethanol which is actually corrosive. There is a big push right now from governments for E15 (15% Ethanol) which would be even worse. All new cars are fine but in my honest opinion, stay away from Ethanol if you can.
The difference is the resistance of the fuel to ignition, not efficiency. Higher octane rating means the fuel is more difficult to ignite. This allows for ignition timing to be more aggressive which is where the extra power comes from.

If you will be lugging the engine along on highway commutes or just low load city driving, there is little need for 91/93 fuel over 87. Now, that's not to say that some fuel manufacturers put less additives in their lower grade fuels, but that is mostly tit-for-tat. The FiST (and pretty much all modern cars to this point) have the proper engine monitoring systems in place that will adjust the timing based on the information logged from the sensors.

I wouldn't worry about low ethanol content fuels. Most manufactures accounted for up to E20 fuels in the design of their fuel systems since the early 90's. The fuel systems that have trouble with ethanol content are the pre-90's systems that didn't have ethanol content in mind, they are mostly at risk due to lean conditions and water absorption than they are to corrosion.
 

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The difference is the resistance of the fuel to ignition, not efficiency. Higher octane rating means the fuel is more difficult to ignite. This allows for ignition timing to be more aggressive which is where the extra power comes from.

If you will be lugging the engine along on highway commutes or just low load city driving, there is little need for 91/93 fuel over 87. Now, that's not to say that some fuel manufacturers put less additives in their lower grade fuels, but that is mostly tit-for-tat. The FiST (and pretty much all modern cars to this point) have the proper engine monitoring systems in place that will adjust the timing based on the information logged from the sensors.

I wouldn't worry about low ethanol content fuels. Most manufactures accounted for up to E20 fuels in the design of their fuel systems since the early 90's. The fuel systems that have trouble with ethanol content are the pre-90's systems that didn't have ethanol content in mind, they are mostly at risk due to lean conditions and water absorption than they are to corrosion.
The higher octane is more efficient. When the spark ignites it, it takes longer to burn and it burns more even, creating less waste and hence being more efficient.

For the ethanol, it is naturally more corrosive than pure gasoline. The older cars are the ones that are effected the worst as their seals and rubbers can swell.

Ethanol is a lot less efficient as well. It does burn at a cooler rate which guys love it for performance, but to run ethanol, if you made 400hp on 750cc injectors, you would need probably close to 1000cc injectors to make the same power and would have roughly the same duty cycle.

I just say stay away from ethanol if you can because it is an option in Canada. I believe Esso and Shell 91oct here does not have ethanol. Everything else is 10-15%.
 

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The higher octane is more efficient. When the spark ignites it, it takes longer to burn and it burns more even, creating less waste and hence being more efficient.
Mythbusting Octane, The Truth About Gasoline

Better MPG with 87 than 91 Octane ? | Fuels and Fuel Additives: Gasoline and Diesel | Bob Is The Oil Guy

Tried finding a couple of examples that cited sources, but such is the life of modern Internet information. Both of the above links are from established websites.
 

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Yes! Please! That means more for me!
Hey I love the idea behind it. Ethanol helps drive up our Corn prices! They have not been this good in a LONG time! I am not saying that ethanol is bad, it just isn't as efficient. I know some guys running some crazy numbers on corn...crazy stuff!
 
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