While most people are familiar with the standard gasoline octane ratings featured at most fill stations (87, 89, and 91), they may not understand exactly what these numbers mean, aside from the fact that higher is better. It’s certainly more expensive and with names like regular and premium you can pretty much do the math. So what’s the difference and why do high-performance vehicles call for more expensive gasoline? Do people who drive these cars really need to shell out for pricier fuel or can they save a few ducats by switching to a lower grade? Here’s the skinny on what the numbers at the pump mean for your car (and your wallet). In truth, there’s not as much difference as there used to be. Early on, premium fuels provided a significant advantage over their “regular” competition thanks to added cleansers that helped to keep dirt and debris from building up in the fuel tank and cycling through the engine. But these days those same agents appear more or less equally in all grades of fuel. What is still true of premium fuel is that it is engineered to withstand the higher rates of compression featured in high-performance vehicles, which is what helps to give sportier cars that extra kick when you put the pedal to the medal. But do you really need it? Will you notice a difference in performance by switching to a lower fuel grade? And can you live with it if it saves you money? You may not notice an immediate difference in your engine performance, at least not in terms of the power output. But let’s say, for argument’s sake, that you could save something like 5% annually on the cost of gas purely by downgrading to a lower octane. That sounds pretty good, right? Unfortunately, you are also likely to sacrifice fuel efficiency by doing this, virtually negating your savings by decreasing your miles per gallon. In the past, you might have experienced the telltale knocking and pinging that indicated misfires (or small explosions out of time with the combustion cycle) due to improper amounts of fuel heating and combusting out of sequence. Thanks to the advent of on-board diagnostics (your car’s computer) and the many sensors that help to track and correct your engine’s performance you will no longer have to suffer with these embarrassing noises. And while this modern system will ensure that misfires don’t occur by adjusting the amount of fuel injected into the combustion chamber, the downside is that you may end up burning through your tank faster. Of course, using lower-grade fuel could also lead to long-term issues that might end up costing you a lot more down the road. Although unlikely with so many sensors making adjustment, lower grade fuel has the potential to put added stress on your engine. This is especially possible if your sensors go out (as they could if they are constantly called upon to make adjustments). If this happens, misfires could occur, stressing the components of the combustion chamber (pistons, rods, valves), which could cause them to wear too quickly or otherwise fail, leading to very pricy repairs. You’re already spending a lot on car insurance, loan payments, registration, and everything else that goes into owning a high-performance vehicle. So if you want to save money, downgrade your car along with your fuel rather than using the wrong octane in the vehicle you currently own.
About the author: Evan Fischer is a contributing writer for Kanetix Insurance Rates, where you can find and compare online car insurance rates with companies like Assurance Auto and browse customer reviews.