MOTORISTS who are thinking of switching to super unleaded gas instead of premium should stop worrying because their vehicles can make the transition without any hiccups, depending on the engine type.

In a telephone interview with the Express yesterday, principal of the Academy of Auto Mechanics Roy Marslier said only high-compression vehicles are supposed to use premium gas.

During the 2012/13 budget presentation on Monday, Finance Minister Larry Howai announced the removal of the subsidy on premium gas, which means the price per litre has been increased from $4 to $5.75.

Many motorists now faced with higher fuel bills have expressed their willingness to switch to the much cheaper $2.70-per-litre super unleaded gasoline, but have wondered whether it is safe for their vehicles.

"People want to put what is best and think that because a fuel is premium, it is best. That is not the case. It is the amount of anti-knock agent in the fuel that makes the difference. Super is just as good as premium," Marslier said, adding that no matter the type of fuel placed in your car, it will start and drive.

"If the engine is a high-compression engine and you have super unleaded fuel, when climbing a hill there will be a knocking (detonation) coming from your engine. This will not damage the engine, but inform you that the car has a high-compression engine and therefore you need to use premium," Marslier said.

Marslier said if a knock is heard, all that needs to be done is reduce speed and change the fuel when possible.

"If you put the super in and you do a Grand Prix and you are a racer, you are definitely going to mash up that engine. You do not want the fuel to self-ignite in the engine. The lower the octane, the greater the chance of that happening. Super fuel is of a lower octane number and more susceptible to that," Marslier said.

Asked about using treatments in the fuel to help with the transition, Marslier said: "There are many old wives tales about this. None of those things are going to help you. People doing all sorts of things because they do not know."

Marslier said all vehicle-makers have high-compression engines in varying models of their cars, and it is not only the high-end vehicles that have high-compression engines, as has been stated by the Government. • See Page 4