Does your car recommend you use premium gas? Or if it doesn’t, when you’re pumping your regular gas, do you ever wonder if you would get a boost by paying for high-test? Or have you ever had an old-school car guy tell you that you need to run premium sometimes to clean out your gas tank?
There’s a lot of confusion out there about premium gas, what it’s good for, and who does or doesn’t need it. So, let’s clear things up once and for all.
Why Do Some Cars Use Premium Gas?
Some cars either recommend that you use premium gas or require it. Many cars will have a sticker inside the fuel door that tells you if it recommends or requires premium gas. You can always check your owner’s manual.
So why would you need premium gas? Cars that call for premium gas tend to either have high compression engines or forced induction (supercharging or turbocharging). That means that the fuel and air is under very high pressure in the combustion chamber. That’s one way to make a high-powered engine.
High compression and forced induction introduce their own complications. High pressure (along with heat building up in the engine) can cause the gas to combust before it should. That’s called pre-ignition, detonation, or engine knocking. Knocking can cause damage to engine components, especially if it recurs over a long time. You can recognize knocking as a metal-on-metal “pinging” sound under the hood.
You may have noticed the different octane ratings on the fuel pump: usually numbers like 87 for regular, 89 for mid-grade, and 92 (or thereabouts) for premium. A higher octane rating means that the gas is less likely to pre-ignite.
Which Cars Require Premium?