Edmunds Answers



  • actualsize 03/25/08 12:33 am PST

    Normally, "recommended" means that you don't HAVE to use it. If they were serious, they would come out and say "required" like a lot of other automakers do. But preimium is what Mazda used for their horsepower and 0-60 tests.

    This car has a knock sensor, electronic ignition and variable valve timing. It can dial back the timing to prevent knock or ping. In order to get the most power and acceleration, then, yes, premium is what you need. But if you drive in an economical way on reasonably level ground in moderate weather, something less than that should be OK. But don't buy the cheapest off-label stuff you can find, either.

    Confusing the issue is the fact that premium is only 91 in most of California, but can be as high as 93 or 94 elsewhere.

    Miata.net is a spirited board visited by a lot of Miata owners. Read the link below to see what other owner's have said.

    Source: http://forum.miata.net/vb/showthread.ph

  • xfiatspider 05/02/12 11:42 pm PST

    Premium is recommended NOT required!

    I have a 2006 Miata and use regular around town with no problems, I don't even notice any lack of performance and if there is a difference in mileage I haven't noticed it. On the highway where I get better mileage I still use premium but most of my driving is around town and to the beach... no highway.
    Buy one you will never regret it, I have a 1980 Fiat Spider as well and the Miata is thousand fold more fun!
    Join "MX-5 Miata Forum" where it has been debated since they came out with the new model (2006).
    Why would you buy an automatic??

  • xfiatspider 05/05/12 11:33 pm PST

    From the owners manual via a nice guy at the Miata NC forum

    Originally Posted by VaderSS View Post
    Do you understand the feedback control that the PCM performs?

    For what you hypothosize to be fact, the system would have to, at the least, go into open loop. I cannot believe that Mazda would not make the wording more forcible if it were true.

    From the owner's manual;

    Fuel Requirements
    Vehicles with catalytic converters or oxygen sensors must use ONLY UNLEADED FUEL,
    which will reduce exhaust emissions and keep spark plug fouling to a minimum.
    Your Mazda will perform best with fuel listed in the table.
    Fuel Octane Rating* (Anti-knock index)
    Premium unleaded fuel 91 [ (R+M)/2 method] or above (96 RON or above)
    * U.S. federal law requires that octane ratings be posted on gasoline station pumps.

    You may use a regular unleaded fuel with an Octane Rating from 87 to 90 (91 to 95 RON)
    but this will slightly reduce performance.
    Fuel with a rating lower than 87 octane (91 RON) could cause the emission control system
    to lose effectiveness. It could also cause engine knocking and serious engine damage.


    Leaded fuel is harmful to the catalytic converter or the oxygen sensor. The lead will
    accumulate on the oxygen sensor and the catalyst inside the converter. This will result
    in a malfunction of the emission control system, causing poor performance.

    l Your vehicle can only use oxygenated fuels containing no more than 10% ethanol by
    volume. Damage to your vehicle may occur when ethanol exceeds this
    recommendation, or if the gasoline contains any methanol. Stop using gasohol of any
    kind if your vehicle engine is performing poorly.

    l Never add fuel system additives. Never add cleaning agents other than those specified
    by Mazda. Other cleaning agents and additives may damage the system. Consult an
    Authorized Mazda Dealer.
    Gasoline blended with oxygenates such as alcohol or ether compounds are generally
    referred to as oxygenated fuels. The common gasoline blend that can be used with your
    vehicle is ethanol blended at no more than 10%. Gasoline containing alcohol, such as
    ethanol or methanol, may be marketed under the name “Gasohol”.
    Vehicle damage and drivability problems resulting from the use of the following may not
    be covered by the Mazda warranty.

    l Gasohol containing more than 10% ethanol.

    l Gasoline or gasohol containing methanol.

    l Leaded fuel or leaded gasohol.

    We are going to try regular.

    PS: I use regular most of the time without problems. (Xfiatspider)


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