what is special unleaded petrol

In Australia, “special unleaded petrol” usually means premium unleaded—the 95 or 98 RON stuff rather than regular 91.

It brings higher octane (better knock resistance) and often extra detergents, but it’s not a magic horsepower smoothie.

If your handbook says “95/98 required,” use it; if it merely “recommends” it, you might find smoother running or tiny economy gains, but your wallet will notice the extra 10–25c per litre.

Engines designed for 91 won’t suddenly grow biceps on premium, though turbo or high-compression motors generally do benefit.

Bottom line: feed your engine the octane it asks for, and save the fancy juice for cars that can actually use it.