A big part of engine maintenance is making sure you select the right type of gasoline for your vehicle. Not only is it essential to use the recommended octane (regular, midgrade or premium gasoline), but it’s also important to make sure your fuel has enough cleaning agents to protect your engine. Let’s get back to the basics to help you better understand what you’re putting into your car.
You probably associate octane with the number you see at the pumps (the higher the number the more premium the fuel), but the technical explanation for octane is the measure of the fuel’s ability to resist “engine knock.” If you use a lower octane rating in an engine designed to use higher octane fuel, “engine knocking” might occur, causing the car to shudder and lose performance. Most modern electronic engine management systems can sense this knocking and make adjustments to prevent serious engine damage, but downgrading to a lower octane can mean reduced performance and lower fuel economy.
Since not every car is the same, different vehicles require different octane gasoline. The vehicle manufacturer’s recommendation for the appropriate octane level is listed in your owner’s manual. Some vehicles may even have the octane requirement noted on the fuel gauge or the fuel filler cap. If your vehicle’s engine is designed to run on regular grade unleaded gasoline, that’s all it should require. However, using octane above the recommended level will not harm the engine. If you are experiencing engine knocking in an older car that recommends low octane, using a higher octane grade may help correct the problem (however, it’s also recommended to have your car serviced). If you have a performance or luxury vehicle that requires a higher octane level, I recommend you use the rating specified in order to achieve optimal engine performance.
The enemy of engine performance and efficiency is engine “gunk,” or harmful carbon deposits. The gunky build-up is the result of various chemical processes that occur during engine operation, creating a build-up of residue on intake valves and fuel injectors. This gunk acts like a sponge, absorbing and trapping gasoline which can result in decreased engine performance.
Some of the world’s top automakers -- Audi, BMW, GM, Honda, Toyota and Volkswagen -- recognize that current Environmental Protection Agency minimum detergent requirements do not go far enough to prevent engine gunk and ensure optimal engine performance. To try to raise the bar on fuel quality, these auto manufacturers designated the voluntary TOP TIER Detergent Gasoline Standards to help drivers avoid lower quality gasolines.
Choosing a gasoline for your vehicle is like choosing a meal for your body -- healthy choices can make a difference. Fortunately, preventing engine gunk is easy. Shell recently introduced TOP TIER-certified Nitrogen Enriched Gasolines, containing a unique, patented cleaning system designed to seek and destroy engine gunk left by lower quality gasolines. The new Nitrogen Enriched formula helps protect and clean critical engine parts in both conventional and modern engines.
No matter what octane level is required for your vehicle, I recommend you always use a high-quality gasoline that meets TOP TIER standards. Industry research confirms that a clean engine can result in better fuel efficiency, reduced emissions and overall optimal engine performance.
The Bottom Line
While most engines will work regardless of the fuel grade or quality, it’s important to understand that using a higher quality gasoline can be a simple step to help maintain your engine and its vital components. In today’s tough economy, American drivers are concerned about protecting the health of their vehicles. Not all gasolines are the same -- the differences in product quality are real. To keep overall costs down, there is no substitute for preventive maintenance.
For more information about Shell Nitrogen Enriched Gasoline and fuel tips
, visit www.passionate-experts.shell.com.
(Sam Memmolo, ASE certified auto technician and automotive expert for Shell)