E5, E10 and octane ratings
E5 and E10 describe the maximum ethanol content in petrol. The 95 or 98 octane number describes resistance to engine knocking. They refer to different fuel properties, so don't treat them as interchangeable labels.
- •E5: up to 5% ethanol
- •E10: up to 10% ethanol
- •Use the minimum octane grade specified by your vehicle maker