Making the Grade: Differences Between Fuel Types

June 4th, 2019 by

Car Fuel Differences

Every time you pull up to the gas station and arrive at the pump you are typically greeted with a choice: Do you go with with regular? How about midgrade? And then there is always premium gasoline? And what about that big, bright yellow nozzle for the diesel? Why are there so many choices when it comes fueling options for vehicles? Here at the Maserati of Kirkland Cars blog, we try to answer all of those questions about the various car fuel differences. Here we go:

Regular Grade:

First of all, gasoline is rated based on something called an “octane level”. What an octane level measures is the the knocking or pinging resistance or lack there of of a gasoline. The higher the rating, the more impervious the fuel is to knocking. Typically, regular grade fuel will be given the lowest rating anywhere between 85 and 88. This means fuel is more easily burned. This is what makes it ideal for vehicles controlled by a powertrain that burns an optimal amount of fuel.

Midgrade/ Plus:

Typically rated anywhere from 88-90, midgrade’s combustion rate is higher than regular grade fuel. This also allows for the fuel to be more resistant to being compressed, and in the process is not going to knock as easily. Knocking can cause engine damage, and commonly occurs when a driver puts a lower than recommended octane grade in their fuel tank.

Premium grade:

Premium has the highest of the three octane ratings, upwards of 90, typically coming in at 92. Sports cars and vehicles that generate tremendous power typically need a tough-burning fuel to avoid pinging or knocking to achieve not only maximum performance, but also avoid engine damage.


This fuel type is a horse of a different color entirely. Diesel is ignited by purely temperature and pressure, whereas gasoline ignition is set off by the spark plugs. While using the wrong grade of gasoline can cause engine damage, the car would still be able to run–albeit at the detriment of the vehicle itself. Diesel in a gasoline engine-fueled would not run at all. Diesel, while also more expensive typically, it gets better fuel efficiency due to having a higher energy density. As such, diesel is heavier–a gallon of diesel is a pound heavier than gasoline–and is much more oily.

Posted in New Vehicles