Does Premium Fuel Actually Make a Difference?

"Premium fuel is just a way for servos to charge more." You hear it all the time. The truth is more nuanced — sometimes premium is worth it, sometimes it's a complete waste of money, and the differences are real either way.

Use the octane your car is designed for. The 91, 95 and 98 you see at the pump is the octane rating — how resistant the fuel is to knocking, which is when fuel ignites at the wrong moment under compression. If your car is designed for 91, putting 98 in it won't make it faster or smoother; you're just paying extra for resistance to a problem you don't have. But if your car requires 95 or 98 — check inside the fuel flap or the owner's manual — running 91 can cause knocking, reduced performance and engine stress over time. So the first rule is simple: use what the manufacturer specifies, no less and no more.

The real difference is in the additives. This is where fuel quality genuinely varies. Better fuels carry stronger detergent additive packages that keep your injectors and intake valves clean. Cheaper or lower-quality fuel can leave deposits that build up over time, hurting efficiency and smoothness. That's not marketing — it's why an occasional tank of good fuel can clean things up when a car's been running a bit rough.

What about E10? E10 contains up to 10% ethanol. It's usually cheaper, but it carries slightly less energy per litre, so you may use a touch more. More importantly, not every car is rated for E10 — older vehicles especially. Check before you fill, because the small saving isn't worth a fuel-system problem.

The practical takeaway: use the octane your car asks for, stick to reputable fuel brands for the additive quality, confirm your car's happy with E10 before chasing that price, and if the car's running rough, a tank of quality fuel is a cheap first thing to try before assuming the worst.

Need a hand? Call Mehdi on 0424 334 080 — mobile mechanic across Western Sydney.