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Breaking startling news from the AAA today. This is a 180 degree reversal from what they have been claiming over the years!
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Drivers are wasting their money if they use more expensive premium gasoline in vehicles that recommend but do not require it, according to new research by AAA.
Premium gasoline — 20% to 25% more expensive than regular nationwide, according to AAA — improved fuel economy an average of just 2.7% in a variety of vehicles the auto club tested in labs and on the roads of Southern California.
The average price in Michigan on Dec. 11 was 26.2% — $2.513 a gallon for regular and $3.171 for premium, according to gasprices.aaa.com. The national averages are $2.462 and $3.007, respectively. AAA says the price difference between regular and premium averages 20% to 25% across the country.
The research gives lie to the widespread belief that car owners benefit from using more expensive high-octane premium fuel in vehicles that run fine on regular. The small gain in fuel economy is more than outweighed by premium’s higher price.
“This becomes increasingly important as the difference between the cost of regular and premium gasoline grows,” IHS Markit senior analyst Stephanie Brinley said. The gap has widened steadily since the Great Recession.



Premium may boost horsepower for some engines, but likely not enough for most people to notice in normal driving. The vehicles AAA tested averaged just a 1.4% increase in horsepower. That may matter at the Daytona 500, but you’ll never notice it on the way to work or the grocery store.
Automakers sometimes advertise higher horsepower figures they attained using premium to attract enthusiasts, and buyers who don’t know how little the difference will mean to them.
“Unless you’ve got a 700-hp twin-turbo engine in a sports car, I don’t think it matters,” said Joe Phillippi, principal of AutoTrends Consulting.

AAA tested six vehicles: a 3.5L Ecoboost Ford F-150, 6.2L V8 Cadillac Escalade, 5.0L Ford Mustang V8; and four-cylinder engines in a 2.0L Mazda MX-5 Miata, 1.8L Audi A3 and 1.4L Jeep Renegade. The Auto Club of California conducted the tests.

While engines that recommend premium deliver little bang for the extra buck, vehicles that require premium should always get the higher octane fuel. Using regular in them will lead to a significant decrease in fuel economy and power, and could eventually damage the engine or emissions control system.
Octane is not a measurement of the amount of energy in gasoline, but of the fuel’s resistance to “knock,” or burning before it’s intended to. Higher levels of octane allow engines to run at higher compression ratios without knocking. The higher compression ratios, in turn, lead to more energy when the fuel ignites in the cylinder.
AAA does recommend drivers use fuel labeled “top tier.” It’s certified to contain the highest level of detergent to reduce the accumulation of contaminants in the engine. That improves efficiency and can extend an engine’s life.
 

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Well, that just deflated my balloon rather quickly lol. This is the reason why I was so skeptic and started a thread a while ago about this subject. I switched to 91 octane last week and I'm still on the same tank as I write this and I wanted to "believe" it would be great for the engine of my brand new 2018. It's very difficult nowadays to firmly believe in something when these guys can switch their point of view all of a sudden. It's like when a nutritionist come up with a claim that coffee is bad for you, then 2 years later he come back saying it good for you. How can we believe anything these days?
 

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If I cared about saving gas money, id go back to observing the speed limit while zipping around town in my shoebaru. Can't do anything without someone criticizing you, like what you're doing is directly impacting them.
 

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So the article says it's a waste, picked mostly cars that recommend it, says they need it or else you could break them costing you more than just pumping premium?

My Cruze hated 87 and once I got tuned it was pointless to use it ever again. Accord w/o turbo and w/o a tune it was a waste.
 

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It's a waste in certain cars, sure, but cars like ours that have severe knock in high temp weather on 87 octane, not so much. Knock is bad and our cars stock are already underpowered, and knock makes them run slower and worse, so I'll 'waste' my money all day on 93 octane, since it's proven to make our little hamster wheel run smoother and quicker.
 

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It's a waste in certain cars, sure, but cars like ours that have severe knock in high temp weather on 87 octane, not so much. Knock is bad and our cars stock are already underpowered, and knock makes them run slower and worse, so I'll 'waste' my money all day on 93 octane, since it's proven to make our little hamster wheel run smoother and quicker.
Happy car = Happy commute. That whole 91 octane tune tease after refuel was painful.
 

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I heard that last night also and they said most cars. They were talking about MPG not performance also. At least from what I heard? I will still use 89 in both my LTs regardless
 

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Heck I knew that, they didn't have to spend all that money on that study.
It's simple math 15-20% more for fuel for +/-5% more mpg is not logical captain.
I use 89 mostly except in the hot summer months I blend 89 and 93 to get 91ish. Each grade in my neck of the woods is 25-30 cents more per gallon. Don't have a station near me with 91. Even if there were it's still the same as 93. I say that because there's a station with 92 and it's the same price as the station with 93.
 

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Yes, peak HP. The Ecoboost engines, Audi 1.8T, and Fiat 1.4T, as well as the Cruze 1.4T, are all tuned to make their peak numbers on 87 octane.

Power under the curve on a turbo engine is VERY different...especially at lower RPM
 

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What a load of crap. I love when people who have no idea how things truly work conduct "studies". Sure, premium is absolutely unnecessary in most lower compression NA cars, but in turbo cars I see it as a must.

If I recall AAA was the same group to publish an article about why synthetic oil is a "waste", meanwhile almost every manufacturer has switched to synthetic oil after issues.
 
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I"m still not seeing any difference between 85 and 91. Mileage and HP. And i don't know how you all could say it's severely underpowered. The 83 cubic inch motor is smaller then the 97 cubic inch my hyundai i traded in but it defenitly has a lot more UMPH. I certainly wouldn't want to romp from a dead stop every time.

And is
9.5 hi compression? When the turbo isn't running. I always thought it had to be above 10.
 

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they need to stop making the midgrade its dumb. Just make two grades of gas period. Price would probably a little cheaper too. Either you use 87 or 91/93 and be done with it. That's all Sam's club sells and it makes sense.
 

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An organization that thrives when vehicles break down and motorists need assistance might be one where the motives should be questioned. Even if the math doesn't make economic sense based MPG alone, one would have to figure in durability of these engines, PAST the OEM warranty... Keep in mind, the OEM will say 87 is OK, but they only want to be sure any problem that occurs is AFTER the warranty period is over. I have calculated that in my 1996 Saturn a larger improvement in MPG than what they found in this study, I'd expect the newer direct injected, higher compression, turbo charged engines to have a bigger advantage, not less, as this article indicates.. Make it easy and don't trust this study or any other do your own testing and calculations and decide from that. Actually that is a good life lesson generally.
 

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they need to stop making the midgrade its dumb. Just make two grades of gas period. Price would probably a little cheaper too. Either you use 87 or 91/93 and be done with it. That's all Sam's club sells and it makes sense.
Most do not have a tank of mid-grade, the have regular and premium, and they mid-grade is a metered mix of the two.. I once worked at a fuel station. Now, some might have an extra tank, but even then it is mix from the distributor.
 
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It seems like spread between the grades doubled fairly recently.
 
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From the 2nd AAA link
If you drive a car whose manufacturer says premium gasoline is "required," and particularly if it is a high-performance car often operated at high-rpm and high-loads, the greater anti-knock capability of premium gas is essential to prevent knocking and provide the maximum rated power output. This is particularly true of engines fitted with turbochargers or superchargers.

Here's the bottom line. If your premium-fuel engine runs fine on regular, you never hear any knocking, and the power it produces is acceptable, your car is unlikely to suffer any problems. However, any time you hear engine knock when using a lower grade of gasoline than that recommended by your vehicle’s manufacturer, you need to step up to a higher-octane fuel. It is also important to read your owner’s manual; the use of regular gasoline where premium is required can void the warranty on some cars.
Earlier debates I pointed out the EPA doesn't use "Pump Gas" to make the calculations. The site has changed a few times so I can't easily find the part where they said the standard was like 91/92 non ethanol octane. Best I can find is this here @ #5.

https://nepis.epa.gov/Exe/tiff2png....NDEX DATA\11THRU15\TIFF\00000668\P100IEND.TIF
 

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I haven't noticed any difference among 87, 89, 91, and 93 with either of my '12 Ecos. and with the well, premium, that mid-grade and premium commands over 87 these days it isn't worth the money anyway.

Wait, I did have an issue early on with surging on 87 octane, but re-gapping the plugs to .032 fixed that.
 

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I think the real people you should be pissed off at are the Chevy engineers. These cars barely run on 87 without knock in perfect conditions but they recommended 87.

Actually, the sales and marketing department probably had more say than the engineers.

I'm not sure why anyone would be mad at AAA.
 
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