This is a common question I get asked when people are buying their new cars. I think that there’s a lot of misconceptions about octane rating and the effect it has on your car. Commercials will often have you believe that a higher octane rating means a higher output, but that’s simply not the case. First of all, always check your owner’s manual for the type of fuel the manufacturer recommends. The reason for that is because some higher performing vehicles require higher compression to run at peak levels.
With modern spark-induced engines, your car’s pistons compress air and gasoline and when the spark hits, it forces the piston away, creating the power that your vehicle has to go down the road. The temperature at which your engine operates during this time is very high and can often ignite the fuel within the compression chamber without the use of a spark, causing your engine to ‘knock’. Higher octane fuels ignite at a higher temperature so it will resist the ‘knock’ of prematurely ignited fuel. As I said earlier, some high performance vehicles recommend higher octane fuels due to the fact that their engines are finely tuned and regular gas may cause a ‘knock’.
Here’s a great video I found going into a bit more detail than I did.
There you have it! Higher octane fuels do not give you better gas mileage or higher power output, it’s all dependent on the engine that’s in your car. Again, be sure to check out your owner’s manual before coming to the conclusion of which octane rating gasoline you need to put in your car. The extra $4-5 per fill-up of higher octane gas is just not worth it if your engine is designed to run on regular gasoline.
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