I realize there are certain motors that run best on high octane gas because they’re designed for it. Is there any overall efficiency for a standard vehicle? What is it doing for my motor that ordinary gasoline doesn’t? I was always told, growing up, that every so often you should run a tank of high octane gas through a vehicle to clean it out. Is this a myth?
EDIT: Thank-you all for taking the time to respond and help me understand!
In: Engineering
Higher octane gas is more responsive to the spark which causes it to combust.
If a combustion engine requires high octane gas, its performance is dependant on the gas changing states (exploding) at the right time.
High octane gas, being more responsive lessens the chance it will detonate at the wrong time.
You are paying for controlled, predictable volatility, not cleaning.
If your car doesn’t require high octane fuel there’s no reason to run it. Octane isn’t a a measurement of the cleaning power of the gas and it’s not advertised as such. A particular brand’s detergent package that they put in their gas is the same across all grades they sell.
Like the others said there’s no reason to run high octane fuel in a car that’s not tuned for it, however if cleaning is your concern I find using a bottle of techron or some other fuel system cleaner every so often can help keep your car running efficiently.
There is exactly one reason to use premium: if you have an engine that requires it, a lot of warranties specify that you have to use the right grade of gas or better, and if anything goes wrong *and* the repair shop analyzes the gas, ts possible that the dealer can deny you coverage under the warranty. As far as the rest goes, gas is, largely speaking, identical.
If you run high octane gasoline you are just wasting funds unless your automobile is rated for it. High octane gasoline actually has less energy then standard gasoline by volume, but high octane gasoline can be compressed more which allows the engine to burn more fuel at once giving you more power per engine stroke.
High octane gas is basically a fuel that is less volatile than it’s lower octane counterparts. A fuel will ignite if it is compressed hard enough and fast enough. This is how a diesel engine works. A gas engine ignites the fuel with a spark plug at a specific time in the rotation of the crank to get optimum power/efficiency. The fuel ideally should burn, not explode.
In high compression gas engines, sometimes the compression will cause detonation of the fuel mixture prematurely. The fuel explodes at the wrong time (too early) putting incredible strains on the piston and linkage. A higher octane fuel, being less volatile, doesn’t detonate.
Running higher octane fuel in an engine that doesn’t need it doesn’t hurt anything but your pocketbook. It doesn’t help anything either.
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