Super vs premium gas

When leaded gas was the normal gas in Trinidad, refineries would boost the octane ratings of cheaper grades of gas by adding lead to increase the octane level.

When leaded gas was banned, refineries could not boost the 85 octane ratings of cheaper grades of gas by adding lead to increase the octane level.

The type of gasoline to use is one of the most misunderstood areas of vehicle ownership.

The first rule of thumb is that unleaded premium 95 octane gasoline is not necessarily better for your vehicle.

A modern day car engine runs on the octane rating of the gasoline sold not on the name unleaded super or unleaded premium.

Unleaded super in Trinidad is rated at 92 octane and unleaded premium is rated at 95 octane.

Octane rating does not relate to the energy content of the fuel it is only a measure of the fuel’s tendency to burn rather than explode.

Most Trinidadians buy unleaded premium 95 octane gasoline for their car because they grew up with the myth and hearsay in the days of leaded gas that using a higher octane level gas will improve its performance, burn cleaner, go faster, get better mileage or run cleaner.

The recommended gasoline for 95 percent of cars worldwide is unleaded super 91- 92 octane.

Ninety percent of all cars, trucks, maxi taxis, and pick-ups on Trinidad’s roads can use unleaded super 92 octane Gas without any problem.

In fact, in most cases, using a higher 95 octane gasoline than your owner’s manual recommends offers absolutely no benefit.

Unleaded premium 95 octane gas does not “burn cleaner” than unleaded super Gas octane 92.

Unleaded premium 95 octane gasoline does not outperform unleaded super 92 octane in preventing engine deposits from forming, in removing them, or in cleaning your car’s engine. You do not have to remove the catalytic converter using unleaded super 92 octane gas.

Unleaded premium 95 octane Gas gives quicker starting. No, it doesn’t. I thought gasoline with a higher octane reduced engine knock. It did in older engines using lead gas and carburettors to regulate air/gas mix.

They cannot as accurately regulate the air/fuel mix going into the engine as today’s computerised control fuel injector system. Carburettors need adjustment, as a part of regular maintenance, to keep the air/fuel mix as accurate as possible.

So many times these adjustments are not made regularly causing too much fuel to be mixed with the air. When this happens the gasoline would not burn completely soaking into carbon deposits.

This would cause a premature ignition of the gasoline due to the intense heat in the engine cylinder creating “engine knock”.

Modem engines are designed to use fuel injectors with computers to accurately control the air/fuel mix under all types of temperature and environment concerns. High octane gasoline has been refined more – it is just a better product.

Additional refining steps are used to increase the octane; however, these additional steps do not necessarily make the gasoline a “better” product for all engines.

They just yield a different blend of hydrocarbons that burn more slowly and also increase the price.

The accuracy of the fuel injectors and computers is based on using the recommended gasoline for that engine.

Generally, new auto mobiles need high 95 octane gasoline only if the manufacturer recommends it.

However, some cars with high compression engines, like sports cars and certain luxury cars, need unleaded premium 95 octane gasoline.

In fact, the US Environmental Protection Agency requires that all octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against the build-up of harmful levels of engine deposits during the expected life of your car.

They do not necessarily need unleaded premium 95 octane gasoline with a detergent additive. Some engines are designed with high-octane fuel requirements.

Forced induction turbo-charged and super-charged engines have higher cylinder pressures so they require higher-octane gas.

I do not claim to be an expert in these matters, but I am only presenting an overview of what I have discovered in my work in the car industry with the different auto manufacturers both in Europe and the US.

Nick John

Diego Martin