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For Cruze owners with the gasoline engine, does ethanol-free premium fuel perform better in terms of economy and power? I'm just curious of other's experience.
 

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I think it runs better and cleaner. That might all be in my head, though, as I haven't seen any mpg or hp difference on the torque app while running it. I'm not a fan of ethanol, so I guess I'm just happier running efree when I can get it.
 

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At first when ethanol was introduced vehicles took a small hit in fuel economy. As time went on the vehicle manufactures remapped the ECU to run better on 10% ethanol. Then 15% was introduced in some states and as time went on they remapped the ECU somewhere around 12% to 13% ethanol. So todays newer vehicles are better setup for ethanol. If you run straight gas with newer cars I don't know how your mileage or performance will change if at all.
 

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My prior car was a 2009 Hyundai Accent.

There used to be a very small Shell station in my city where the owner (who worked there for like 64 years before retiring) sold ethanol-free gasoline. You could get regular or 91 octane premium for about 10¢ per gallon over the price of anyone else it town. I never noticed any difference in fuel economy between his fuel and 10% ethanol fuels. I continued shopping with him to support a small business.

There was also a fuel station with an ethanol blend pump where you could choose 10%, 15%, 30%, 50%, or 85% ethanol. 50% would throw a CEL but 30% would not. Routinely filling up with 30% would decrease my fuel economy by about 3-5% but the price discount was far greater than that, so it was economically beneficial to fill up with 30% ethanol fuel.

At my parents' house there was a Phillips 66 station that offered 93 octane premium, but it was 10% ethanol. Another notable oil company with a fleet fueling station sold ethanol-free 87 octane at an outrageous markup. That oil company closed their fleet fueling station so the Phillips 66 stations in town (3 of them) now offer ethanol-free premium, but the octane rating dropped from 93 to 91.
 

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At first when ethanol was introduced vehicles took a small hit in fuel economy. As time went on the vehicle manufactures remapped the ECU to run better on 10% ethanol. Then 15% was introduced in some states and as time went on they remapped the ECU somewhere around 12% to 13% ethanol. So todays newer vehicles are better setup for ethanol. If you run straight gas with newer cars I don't know how your mileage or performance will change if at all.

For carbureted engines it did offer better emissions. The extra oxygen in the fuel with the 10% ethanol basically tricked the engine into running a lean mixture so you got somewhat better tailpipe emissions.

The biggest problem/fraud with 10-15% ethanol is we use it as an octane improver. Oil refineries blend regular unleaded to something below 87 octane and then use the 10-15% ethanol to boost the octane ratings up to that 87 or 88 figure at the pump.

Now that turbocharged engines are becoming the majority, we ought to be having a nationwide push to make 89-90 octane the new "regular" unleaded rating and having 92-93 octane as premium fuel. We could have turbocharged gasoline engines running higher compression ratios and higher boost levels to achieve better fuel economy. It would be a nationwide benefit to do this.
 

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Many countries worldwide offer one grade of gasoline. Some with and without ethanol. Each country has their own regulations. You make a valid point. Gasoline in countries that offer one grade have a octane ratio of 91 US or 95 RON European. So 91 octane US is premium grade. Anything above that is considered super or super premium. So if you have a vehicle in the US that calls for premium fuel then that's referring to 91 octane. My motorcycle calls for premium grade and specifically states 91 octane because it has a 12:1 compression ratio. My Honda S2000 also calls for premium grade. I don't know the compression ratio but I would guess it's also 12:1. There are other factors that you should consider in choosing the correct octane rating for your vehicle. Turbo or Super charged, seasonal temperatures and altitudes.
 

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Tried it a handful of times, and I think it runs smoother on 93E10 than 91E0. MPG was about the same too.

Anecdotal though: our naturally-aspirated VW does ~3 MPG better highway on the stuff when we've used it on the same trip vs the 89 it's usually fed. Could be octane difference, could be lack of ethanol.
 

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Anecdotal though: our naturally-aspirated VW does ~3 MPG better highway on the stuff when we've used it on the same trip vs the 89 it's usually fed. Could be octane difference, could be lack of ethanol.
I would argue it's the lack of ethanol. Gasoline has more BTUs per gallon than ethanol. Thats the main reason ethanol nets lower MPG than gasoline. Octane has little to no effect on fuel economy.
 

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I would argue it's the lack of ethanol. Gasoline has more BTUs per gallon than ethanol. Thats the main reason ethanol nets lower MPG than gasoline. Octane has little to no effect on fuel economy.
Unless it's tripping over the knock sensor constantly (usually turbo motors like the Cruze). I don't think this one is on 89, although it does lack low end grunt on 87 that it gets back on 89+
 

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Just my opinion. If your running a boosted engine you should up the octane rating. 89 is a good start but I would run 91 if you can find it. What I mean is many fueling stations have 89 or 93. New engines have so much technology that many will argue that the manufacturer says to use 87. True but they want you to keep costs down to make sales. Behind the scenes under the hood those sensors are compensating for the lower performing 87 octane fuel.
 

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Discussion Starter #11
Octane has little to no effect on fuel economy.
In extremely limited circumstances for naturally aspirated engines, it does. I have a friend (former coworker) with a Dodge Ram 2500. The V-10 engine is his pickup required premium if it's doing heavy towing. Mid-grade is OK the rest of the time.
 

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Unless it's tripping over the knock sensor constantly (usually turbo motors like the Cruze). I don't think this one is on 89, although it does lack low end grunt on 87 that it gets back on 89+
Yes, tripping over the knock sensor will affect fuel economy, but thats only an indirect effect. Octane itself isn't causing lower economy, the ECUs reaction to SPI is. But, I get your point.
 

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In extremely limited circumstances for naturally aspirated engines, it does. I have a friend (former coworker) with a Dodge Ram 2500. The V-10 engine is his pickup required premium if it's doing heavy towing. Mid-grade is OK the rest of the time.
When the truck is towing, it's under extreme load so it's more likely to experience SPI. It's the same as an engine that doesn't knock under 1/2 throttle but the same engine will knock if under WOT. Increase in load can contribute to detonation.
 

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When the truck is towing, it's under extreme load so it's more likely to experience SPI.
This truck is a 2003 Ram 2500 with the Magnum V-10. That new generation of truck switched the air box to the passenger side and the V-10 engine has the intake manifold with the throttle body on the driver side. Dodge didn't want to make any expensive changes to the intake manifold, so their solution was a pipe that runs across the top front of the engine compartment between the manifold and the radiator, does a U-turn, and goes into the throttle body. The result is when doing heavy towing, the pipe is exposed to high under-hood temperatures from hot air flowing out of the radiator. The result is absolutely atrocious fuel economy when towing because the engine is running rich to try to avoid detonation. Think of the torture those catalytic converters go through with that excess fuel!

Our solution was to take a junkyard hood, cut a hole in it, and weld up a sort of "corral" to have cold air flowing into a shorty cone air filter put right on the opening of the throttle body. Then we welded up a small hood scoop to bring in fresh, cold air and bathe that air filter and throttle body in cooler air.

The end result put fuel economy back where it should be. The engine was rated for 89 octane unleaded, but when towing anything really heavy he runs 91-93 octane.
 

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I tried some 91 ethanol-free fuel last fall but it didn't really seem to have any effect other than the mpg went up slightly.

This summer I've been running about a 50/50 blend of e85 and 93, give or take. Mileage dropped to about 20-25mpg where I was getting about 30-35mpg. We were having some really warm weather (90+ degrees) and driving home in the evening, the car was pulling a lot of timing because it was so hot. Blending in some ethanol between 30-50% made a huge difference. My car isn't tuned to run on it, but it is adding about ~15% to the fuel trim so it is 'safe' in that regard.
 

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I tried some 91 ethanol-free fuel last fall but it didn't really seem to have any effect other than the mpg went up slightly.

This summer I've been running about a 50/50 blend of e85 and 93, give or take. Mileage dropped to about 20-25mpg where I was getting about 30-35mpg. We were having some really warm weather (90+ degrees) and driving home in the evening, the car was pulling a lot of timing because it was so hot. Blending in some ethanol between 30-50% made a huge difference. My car isn't tuned to run on it, but it is adding about ~15% to the fuel trim so it is 'safe' in that regard.
You can really mess with emissions doing that.

But yes most GM gassers the past 10 years are stock ready for E100. Just lack the sensor and programming.
 

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You can really mess with emissions doing that.

But yes most GM gassers the past 10 years are stock ready for E100. Just lack the sensor and programming.
288446
 

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For Cruze owners with the gasoline engine, does ethanol-free premium fuel perform better in terms of economy and power? I'm just curious of other's experience.
I would think the cost of premium fuel would the thought of premium fuel. Follow the owners manual recommendation. They is no increase in power or economy by using premium.
 
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