Premium gas is more expensive. it lowers the octane of the fuel, which allows it to burn cleaner and prevent engine knocking. if you put this type of gas into your car then the engine's computer will compensate for this by setting a lower ignition spark advance (retarding timing). this can lead to decreased fuel efficiency and increased emissions.
is it bad to put premium gas in a regular car?
i hear this question a lot so let's do some math to answer it. in general, there is no reason to use premium gas in a gasoline engine unless you have a specific model of car the manufacturer recommends using the fuel for. so i don't think you'll be able to tell much difference by for filling for your next fill up.
however, if you continue to fill with premium gas year after year, it may work out more expensive than filling with regular grade (due its high octane) and it may also lead to quicker deterioration in your vehicle's performance over time due higher temperatures during combustion that occurs with usage of premium gas. again, use whatever type of gasoline is recommended by the manufacturer or try using
can premium gas hurt my engine?
this depends. premium gas is marketed as having higher octane, and therefore less liable to detonate. the downside is that the fuel burns hotter, which could overheat your engine (though this isn't usually much of an issue if you're equipped with a cooling system). premium gasoline also costs more than regular gasoline–meaning it's probably not worth the additional cost unless you like to drive fast or race cars.
if you don't drive much (or at all), then premium gas may be worth it because after about 13 months, regular unleaded fuel becomes ineffective in maintaining an engine's performance. likewise, if you know your car tends put out high carbon monoxide emissions on a regular basis due to being modified or repeatedly driven
what happens if you accidentally put premium gas in your car?
it will behave like normal gas.
most modern fuel systems cope with the difference in octane ratings and adjust accordingly, with higher octane fuel often producing a slight increase in power during acceleration and top speed over low octane fuels. octane ratings only matter at high boost levels, such as those found on motorsport engines or gearbox designs that use automatic shifts. for most passenger cars under most driving conditions, the effects of using higher-octaine fuels are negligible if not actively damaging to one's vehicle.
it is illegal to pump premium gas (rated at 89-94) into vehicles designed for regular gasoline rated 87 primarily because of knock retardation benefits on 16-valve engine operations pump enough air/fuel mixture
what happens if you put 91 gas in a 87 car?
the car will likely not be harmed by the extra 3 gallons of gas.
adding an incorrect amount of gas to a vehicle has no significant consequences. while it may be tempting to just dump 2-3 gallons into an empty tank, this practice does not work well because the fuel pump can't handle that much liquid at once and it just comes out as streaks or globs on the ground. it is probably advisable to find one station where you'd like your vehicle to get filled up again instead of disrupting all our other stations. for example, if you accidentally put 91 octane gas in a 87 car, try getting your next fill-up at a station with 91 octane too – preferably alphabetically adjacent (abc) or within