Do you get more gas mileage for using premuim?

Question

my boyfriends car says on the inside of the gas door thingie "use unleaded only" and then under it it says "use premium only" why does it say use unleaded only if under it it says use premium only? does that mean he can use both? and if he uses premium will he get better mileage?

Answer 1

your boyfriend will get better gas economy if he adds something to his vehicle to increase his mpg at least by 50% perhaps getting 100 mpg or better ... interested?

Answer 2

no you dont

Answer 3

No, you get more gas milage by turning of the aircon, winding up the windows, driving with a very light foot, turning your engine off when stopped at red lights, emptying all non essential junk out of your trunk, maintaining correct tire pressures, removing things like roof racks etc. any or all of these will definately improve mpg as will not making unnecessary journeys.

Answer 4

All gas sold in the US is unleaded.  Leaded gas was made illegal a while ago.

If it says use premium, he needs to use premium or it will damage the engine.  

The gas mileage is not affected.

Answer 5

>>  does that mean he can use both?

Premium is unleaded premium (all gas are unleaded now).  So you MUST use premium only.

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>> do you get more gas mileage for using premuim?

No.

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The difference in Octane on measure resistance to Self ignition or auto-ignition from high compression (like turbo engine).

Octane rating does not measure anything else - not the energy content (not more potent), not cleaner, not better mpg,

NOTHING

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http://en.wikipedia.org/wiki/Octane_rati...

Search down for this statement:

--- "It should be noted that octane rating does not"

--- "relate to the energy content of the fuel"

Good Luck...

Answer 6

The unleaded portion means that the gasoline must not contain lead else damage will result. Lead used to be a standard feature, but it is now limited to certain racing fuels. It is a misnomer to call 87 octane fuel "unleaded" and the other grades by different names. They are all unleaded.

The premium portion means that you must use premium, or 92 octane fuel or higher grade fuel. This means that the engine will knock or detonate if you use anything less. It's not a matter of mileage, it is a matter of not destroying the engine in time. While a rare partial tank of lower grade fuel will get you by if they don't have 92 octane fuel, continued use will significantly shorten the engine's life.