Fuel Price Hike: Turbo Car Owners Shouldn't Risk Switching to Lower Octane

JAKARTA, KOMPAS.com – The increase in non-subsidised fuel prices that has occurred since mid-April 2026 is causing many vehicle owners to think creatively to cut expenses, including by downgrading their fuel type. One of the most noticeable impacts is the spike in Pertamax Turbo prices, which now exceed around Rp 19,400 per litre from the previous Rp 13,100 per litre. This situation is sparking new concerns, particularly for owners of turbocharged cars who risk choosing the wrong fuel for efficiency reasons. “Turbo engines operate under higher pressure and temperature, making them highly susceptible to knocking if using fuel with an unsuitable octane rating,” said Jayan to Kompas.com on Tuesday (21/4/2026). He explained that knocking, or premature detonation, occurs when the air-fuel mixture ignites before the intended time. In turbo engines, this condition is more likely to arise because the incoming air is compressed, significantly increasing pressure inside the cylinder. The issue is that knocking symptoms are not always clearly felt by the driver. In modern cars, the electronic system will attempt to correct the situation by retarding the ignition timing to keep the engine safe. However, this adjustment comes with consequences. Engine power can decrease, acceleration response becomes slower, and fuel efficiency actually worsens. In the long term, using fuel with a lower octane than recommended can accelerate component wear. Unstable combustion pressure can cause abrasion on pistons, piston rings, valves, and in extreme cases, lead to permanent engine damage. Several engineering references, including the journal Applied Thermal Engineering, state that engines with turbochargers have a higher tendency towards knocking due to increased intake air pressure. Therefore, using high-octane fuel is crucial to maintain stable combustion.