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As we're sure you've noticed by now, General Motors has been making lots and lots of waves over the past few days announcing the pricing information (finally!) of its 2011 Chevrolet Volt. And, you also likely know that the car is capable of traveling at least 40 miles per charge without using a single drop of gasoline. But hat happens when the time comes that you need to pump some good ol' crude into the tank? You'll be using premium.

Yes, you read that right. It's premium unleaded only in GM's mostly gasoline-free automobile. It seems a bit odd that The General would force its customers into using higher-priced gasoline if there wasn't a good reason for it, especially since it doesn't seem that the engine is highly stressed – 80 horsepower from 1.4 liters isn't exactly bleeding edge.

There is a possibility, however, that the car's engineers were able to wrestle a bit more efficiency from its constant-load engine/generator setup by using higher octane fuel. In any case, the automaker has not offered up any specific explanations on why premium is required... or, for that matter, what kind of fuel mileage the Volt will attain when the gasoline-powered engine is in operation.

We do feel compelled to point out that it probably doesn't really matter all that much that the Volt requires premium fuel considering how little gasoline the average user is likely to go through any given month, but still...

Your mileage may vary, indeed.

[Source: GM, The Truth About Cars]


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    • 1 Second Ago
  • 64 Comments
      • 4 Years Ago
      Premium gas, so what? A couple extra bucks per tank - maybe.
      Plus for the most part you'll never use any gas, or else you shouldn't be buying an electic car, should ya?
      Else just buy a Fiesta, it's half the price anyway, and be done with it.
      • 4 Years Ago
      First they said it would burn E85, then they said it cant, now they say it can even use regular. Toyota will have fun with this and the volt's 41k sticker price when they trot out the plug in prius.
        • 1 Month Ago
        The Plug in Prius can drive a maximum of 13 miles on battery or a top speed of 62 mph. I don't think Toyota will be tossing barbs on octane. Anyhow, it won't be here until 2012 and the landscape may be very different by then.
        • 1 Month Ago
        "it won't be here until 2012 and the landscape may be very different by then."

        You got that right. November 2012 things will be very different.
      • 4 Years Ago
      What kind of premium?
      Many times when a vehicle that uses 95RON fuel, and is brought to our shores the recommendation becomes 91AKI or better.

      If you actually use more gas than an average Volt owner, how about mid-grade?
        • 1 Month Ago
        I believe the engine is an Opel 1.4L unit as used in the Opel Corsa and Astra over here. It will have a high compression ratio as it's designed for getting the most out of 95 RON, which is the standard product here (it's marked 'Premium' but there is no regular - there are usually 100+ RON 'Super' grades). If you use 87 AKI it will knock and run on retarded timing, which will reduce fuel economy.

        It's slightly depressing to be using Premium fuel in the Prius, where the effective compression ratio doesn't make effective use of it. The quoted compression ratio of 13.0:1 is really the expansion ratio - the Prius' Atkinson-cycle engine uses very late intake close, which means it doesn't actually start compressing until the piston is quite a way up the cylinder. In fact Toyota Motor Sales USA say *not* to use premium fuel in the Prius, it can be a cause of running problems.
      • 4 Years Ago
      Why anyone wouldn't want to put premium fuel in their brand new $41k car is beyond me. What's the markup? Less than $5 a fill up? You could find that on the ground...
        • 1 Month Ago
        It is an econobox battery carrier that costs $41k. Cruze costs $17k and runs on regular gas. Just because Volt's plugin premium is $24k, it does not justify running on premium gas.
        • 1 Month Ago
        It is a fallacy that premium fuel is better for your car.
        Your engine was designed to run with a particular octane rating and that is the fuel that should be used for it.
        If you buy a $100K car and the manual says use regular unleaded and you use premium then you are not doing your engine any favors.
      • 1 Month Ago
      This whole range extender thing keeps looking less and less appealing.
        • 1 Month Ago
        Climber, I'm with you . . . it is silly to make a conspiracy theory over it. I'm sure it was done for some reason like maximizing efficiency or premium gas not going 'stale' as fast as normal gas.

        But like others, I find the progression from E85->normal gas->premium only disappointing.
        • 1 Month Ago
        "It appears as though it was the last chance GM had to do big oil a parting favor."

        Ya, sure. GM's fuel economy as a whole is near the top of the heap and they spent $750M on this project yet are conspiring with oil companies to use even more oil.

        And it's the right wing wackos who are accused of wearing the tin foil hats.....
        • 1 Month Ago
        High Climber: Both right wing and left wing have tin foil hats of their own, dude..

        Is it possible for you to leave politics out any post you make on here? ...

        Anyway. I'm no fan of e85, but i wish it had the capability at the very least. I'm with spec on the disappointment of the fuel choice. Having to use premium gas is a 'worst case scenario'..
        • 1 Month Ago
        Wouldn't that be nice if that were truly the case? :)
        • 1 Month Ago
        It appears as though it was the last chance GM had to do big oil a parting favor.
      • 4 Years Ago
      It nees premium gasoline due to the chance that it will not get used for a long time.
      As gasoline ages, the octane rating is reduced, leading to higher risk of premature combustion.
      Unlike premature ejaculation, you can't just use a condom or desensitizing cream.
      • 4 Years Ago
      Chevy Cruze with turbo is said to run on 87 Octane regular gas. Go figured!
        • 1 Month Ago
        I doubt that. The turbo 1.4L motor does not have direct injection after all. The boost level is gonna be high enough that you'd need 89 octane.... at the very least.

        Unless they've caught on to Ford's magical 'run high compression on 87 octane' trick, which honestly i still don't understand..
      • 4 Years Ago
      I posted this on the other side. I bet it is the same reason why we didn't get a proprietary engine or an Atkinson cycle engine- the low volumes don't justify the cost:

      I bet I know what it is. The 1.4l engine used as a range extended was engineered in Korea specifically for economy cars in EU and Asian markets where higher octane is standard. Given the relatively low volumes of this engine being sold in the US (as, to my knowledge, the naturally aspirated version is not being sold in any other vehicle here), they probably did not want to re-engineer the engine for low octane fuel. Since in 2012 the Voltec powertrain will be sold globally and it will not make any difference to most of the other markets, it only effects the ~10,000 US Volt buyers.

      Considering the high price and limited production, GM probably figures it will be sold out anyway and will not make much difference to those with enough money to buy it.
        • 1 Month Ago
        I think GM are bringing out a film:
        'A Bodge Too Far'

        I always distrust companies who write too much knocking copy on the competition - they are often trying to distract attention from their own mess-ups.
      • 4 Years Ago
      I think ultimately this is a failure for them.
      This car is about efficiency.
      They are selling a maybe $20K car for $41K due to its cutting edge technology bringing efficiency.
      If there is something about the engineering that required this - then that should have led them to make different engineering choices.
      Today - premium is about a 10% increase in price over premium.
      That difference can vary with time and market conditions.
      Any way you look at it - from a use perspective this vehicle is 10% less efficient than it could have been on gas.
      If I am wrong about that - then somebody should be able to show across the board that engines which burn premium are more efficient on average than similar sized engines which do not require it.
      I don't think that will be the case.
      • 4 Years Ago
      They should have instead designed the engine to run on E85, LOL. Well, ethanol *is* high octane...
      • 1 Month Ago
      Add,

      Purely an anecdotal to my "high heat" hypothesis, but on the web chat thingy when one of the Tonys was explaining the premium fuel, he did use the word "knock". I thought this a bit odd to even bring "knock" into the hawking. I mean, if they were running a high compression engine for better efficiency, seems like you'd just say it -- really this should be a selling point -- sort of an upgrade.
        • 1 Month Ago
        Yup. I had hopes, but lately they've been dashed. GM has disappointed us again.
        I should have known. That's OK, you can always get an old Prius and convert
        it to PHEV, or maybe you can find an old Solstice or Sky to convert to BEV.
        Check these guys out:
        http://www.calcars.org
        http://www.ampelectricvehicles.com/
        • 1 Month Ago
        DM@15

        It is all, of course, speculation. But it seems likely given what we know. I look forward to the day when the Volt gets a 'real' independent test drive/shake down.


        I would think the specs on the engine should come out sometime soon. But then again, there may be nothing more revealed until after the IPO.


        http://www.misterfixit.com/deton.htm
        (a nice little write-up on detonation and pre-ignition)
        • 1 Month Ago
        Thanks for some informative posts. The more I hear about the Volt, the less I like it.
        There is nothing wrong with the idea of a range extender, but this seems to me to be a badly sorted project which misses all the important goals.
      • 4 Years Ago
      Perhaps it's needed due to cold start emissions requirements? Seems to me you would be doing an awful lot of that during the course of its life.
        • 1 Month Ago
        All I know is that an engine that is designed to run on premium fuel needs it. My 3.5L VQ Nissan engine gets 550 kms to a tank on regular, 750 - 800 kms on premium with a 40 hp reduction in engine performance on regular to boot. If the manufacturer states use regular gas don't waste your money and use premium, but don't scrimp if the engine needs the good juice.

        FYI I haven't found any difference between 91 octane and Sunoco 94 octane with my car.
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