Since the price of nonsubsidized gasoline, such as Pertamax and Pertamax Turbo, has risen, many vehicle owners have switched to subsidized gasoline (Pertalite). However, they are actually aware that there is a difference in the octane rating (RON) between these two types of gasoline.

What many may not realize is that different car makes and models require different octane ratings. Information regarding the octane rating required by the manufacturer is listed in the owner’s manual.

So, if the manual specifies the use of 92-octane gasoline, that means you must fill up with gasoline of that octane rating or higher, such as Pertamax, Vivo Revvo 92, or BP 92.

The required octane rating is determined by the car’s engine compression ratio. Octane 90 is for engines with a compression ratio below 10:1, octane 92 for a compression ratio of 10:1–11:1, octane 95 for a compression ratio of 11:1–12:1, and octane 98 for a compression ratio above 12:1.

So, what are the negative consequences of using gasoline with an RON that doesn’t meet the manufacturer’s specifications? Here’s the full explanation.

4 Negative Consequences of Using Gasoline with the Wrong RON

1. Engine Knocking

Essentially, octane is a measure of a gasoline’s resistance to spontaneous combustion under pressure. If the octane rating used is lower than required, there is a risk of pre-ignition—or premature combustion—in the engine.

This means that during the compression stroke, the gasoline ignites on its own due to piston pressure before the spark plug fires. As a result, the engine knocks, performance decreases, and fuel consumption increases.

2. Shorter Spark Plug Life

Using gasoline with a lower octane rating than required also leads to incomplete combustion, resulting in soot or combustion residue that can shorten the life of the spark plugs.

For example, while a spark plug typically lasts about 40,000 kilometers, the soot produced by low-octane gasoline can cut that lifespan in half.

3. Carbon Deposits in the Combustion Chamber

Using gasoline with a lower octane rating also causes the combustion chamber to become dirty and filled with carbon deposits due to incomplete combustion.

In the long run, engine power will gradually decrease due to the accumulation of carbon deposits in the combustion chamber. These carbon deposits come from unburned gasoline residues.

If left unchecked for too long, the engine will suffer damage, particularly to the pistons, connecting rods, and valves. This is especially true for cars with modern technology or luxury vehicles, where damage can occur more quickly.

4. Damage to the ECU

Lower octane fuel also has the potential to damage the Electronic Control Unit (ECU). This device acts as the car’s “brain.” Therefore, if it malfunctions, it can cause the car to run abnormally or even stall completely.

ECU damage is indicated by the engine check light coming on, the car failing to accelerate when the gas is applied, and eventually the engine stalling. In some cases, the car may only be drivable for a few kilometers before the engine stalls immediately afterward. Even if the engine can be restarted, it will inevitably stall again.

The solution, of course, is to take the car to a repair shop for service and make it a habit to use gasoline with the appropriate octane rating.

Convenient Car Rentals for All Your Mobility Needs at TRAC

These are some of the negative consequences of consistently filling your car with gasoline that has an octane rating unsuitable for its needs.

Issues like a car breakdown or technical problems on the road can certainly disrupt your plans. However, with TRAC’s car rental service, such situations are guaranteed not to occur because all TRAC vehicles undergo routine maintenance and regular inspections.

Additionally, every TRAC service plan includes roadside assistance. So, if you encounter any problems on the road, you’ll receive help immediately. A replacement car is even available when needed.

TRAC offers daily, monthly, and even annual car rental services. The selection of cars is diverse, so you can choose one that suits your needs. Furthermore, their condition is guaranteed to be safe and in top shape because they are always routinely inspected and serviced on a regular basis.

TRAC is a business unit of PT Serasi Autotaya (SERA), which is also part of the Astra Group, and has over 39 years of experience providing vehicle rental services to both companies and individuals.

For more information about TRAC’s services, visit the TRAC website at https://www.trac.astra.co.id/ and follow us on social media:

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