What are the differences in various grades of gasoline and how do they affect a vehicle?
They higher grade of gasoline the ignation becames less “explosive” and mores mooth and lenear. That us importans because when materials heats they do expand. Explosive ignation leads to high heat pikes thus it is nessesarry to make bigger distance between puston walles and its casing, otherwise it can stuck due to material expansion. The bigger distance between walls – less eficient cooling system and less efficient combustion overall (because not all fuel burns). Thus engine designed for higher grade fuel would be more efficient and will have more power.
You can pour higher grade gasoline into engine which was designed for lower grade. There wouldnot be any drawback not improvements in performance.
You cannot pour lower grade gasoline into engine which was designed for higher grade. Sooner or later that will break it
To understand this, we need to first understand how your average four-stroke gas engine works to generate power. There are four phases, four strokes, in the engine’s cycle:
In the intake stroke, the cylinder draws fuel in. This fuel is then compressed in the compression stroke, then ignited by the spark plug in the power stroke; waste products are then vented in the exhaust stroke.
It’s the compression stroke that interests us here. The more you compress the gas/air mixture, the more power you can extract from it when you ignite it. However, the more you compress it, the more likely it is to ignite itself from the sheer heat before everything’s in position and the spark plug is ready to go.
This out-of-phase ignition not only means you’re not getting the right amount of power, but it can also seriously damage your engine — the “knocking” noise that it typically produces is the sound of bits of your engine smacking into one another.
Okay, so what’s that got to do with the octane rating, the number you see by the gas pump that dictates its grade? Well, the higher the octane rating, *the more resistant it is to premature ignition.*
This means that it will withstand being compressed more before it spontaneously ignites, meaning you won’t get knocking, meaning you’re not damaging your engine.
It should be noted that beyond that knock resistance, a higher grade of gasoline is not “better than” a lower one, and you’re just wasting money putting premium gasoline in a car that asks for regular.