Why do some vehicles run better and have fewer problems than others? Could it be as simple as the gasoline purchased? Many people believe premium or high octane fuel is good for their cars and burning it every now and then is good to “clean things out.” Unfortunately, the only thing that will be cleaned out are funds in fuel purchase.

The only benefit high octane gasoline offers is resistance to pre-ignition or knock, which the octane value indicates. Octane has nothing to do with gasoline’s cleanliness or potency.

Just What is in Gasoline?

Gasoline comprises different oil base stocks. After the refining process removes undesirable components, additives and detergents are blended with the remaining fuel to achieve a unique recipe or blend. Each blend reflects a complex balance of chemicals that may be seasonally adjusted to aid desired performance in certain temperatures and provide varying degrees of cleansing or detergent agents. Of particular issue is the nature and amount of additives that comprise a detergent package.

Measuring and controlling gasoline in the fuel delivery system is critical to an engine’s overall performance and efficiency. In modern engines, fuel can be measured and regulated precisely to control any variable or factor in the fuel or its production. A tank of gasoline with minimal detergents and other additives is prone to form gums, varnishes, and other properties that promote coking and deposits.

These undesirable properties, even in very small amounts, not only inhibit fuel performance, but also precipitate harmful conditions inside the motor itself, leading to poor vehicle performance and drivability, reduced fuel mileage, and significantly increased emissions. Specific damages include carbon build-up, sticking valves, gumming, varnishing, reduced spray patterns, dribbling, engine hesitation, stumbling, rough idle, and overall poor performance.

Selecting a Fuel Grade

When selecting a fuel grade, be sure to follow the vehicle’s owner’s manual and/or instructions on the fuel gauge. If no special fuel is indicated, the lowest octane fuel available may be purchased safely. If, on the other hand, mid-range or high octane is indicated, those instructions should be followed.

Virtually all engines manufactured during the past 15 years have incorporated knock sensors that assist the vehicle computer in optimizing engine controls, thus maximizing economy and performance. Regardless of the gasoline grade used, the engine manages input values and makes adjustments many times per second, controlling the tendency to knock before it even happens. Thus, if not designed to operate on mid-range or premium fuel, a vehicle achieves no benefit from its use, and the cost of extra octane goes right out the tailpipe.

Fuel quality can be measured in another, more meaningful way via the additive package, especially the detergents added to base stocks at distribution terminals. Different gasolines in a specific market area, in fact, may be drawn from one, two, or a small number of distribution terminals. In most instances at a final bulk transfer point, special additive packages are blended with the fuel. That particular supply of fuel achieves a specific profile or recipe as prescribed by the oil or fuel company designating it as its brand.

Many companies promote the detergent aspect of their gasoline products, a factor that plays a vital role in the health and well being of any gasoline engine.

[PAGEBREAK]Food and Gasoline for Thought

Gasoline is the same energy source to an engine as food is to humans. If the diet we consume is not favorable, health problems can occur immediately or develop over time. Either result is difficult to reverse and can produce premature aging and/or long-term health conditions.
Similarly, the fuel used in a vehicle engine impacts its long-term health.

Depending on detergent quality and other additive qualities, or lack thereof, some gasoline products are “junk food” to an engine while others are well balanced and provide good nutritional value.

It was not until the late ’80s that certain aspects of fuel were carefully examined. In 1995, the Environmental Protection Agency (EPA) mandated minimum detergent values for all gasoline sold in the United States, primarily to reduce harmful emissions. Minimum detergents also provided relief from other conditions harmful to efficient and long-term engine operation.

By 2004, several of the world’s largest engine manufacturers determined the EPA minimum standards were not adequate and developed their own gasoline detergent specifications. Joined in 2007 by two other major vehicle manufacturers, top-tier gasoline specifications were established. Vehicle manufacturers believed the new specifications represented the true level of detergent additives necessary to create a healthy diet of gasoline.

While many gasoline “brands” and regional distributors are listed as top-tier gasoline, some major national brands remain absent on that list. Although they may not be included, most national brands that promote their own detergent or cleaning additives should provide satisfactory results.

How important is the detergent in gasoline? This varies with the refined stock, the engine itself, and the driving habits of the operator. Also, in certain parts of the country, spot checks have revealed even minimum EPA requirements are not being achieved at some retail outlets.

“Better” fuel, measured by its detergent properties, is not to be confused with “premium” fuel reflecting octane levels. A fuel’s octane level does not correlate to its detergent attributes. Thus “premium” fuel purchased with higher octane than needed still contains the absolute minimum amount of detergents. It is also important to remember that unless the fuel gauge or owner’s manual specifically indicates a high octane fuel (91 or 93), all other engines are designed to operate on the lower grades.

Researching Fuel Quality

If your favored brand of gasoline is not listed on the top-tier Web site www.toptiergas.com and its producer does not promote its own detergent or additive package, questions may need to be asked. While there may be a few cents-per-gallon difference between various gasolines in each market, often price relates to quality as measured in the additive and detergent packages contained in the gasoline product.

In as few as 10,000 miles, significant and costly damage can be clearly observed in engines that consume low-quality gasoline on one end of the quality spectrum, compared to engines operated more than 250,000 miles that exhibit minimal deposits or damage using top-tier fuel, regardless of octane rating.

The adage of “pay now or pay later” holds true with fuel quality. In addition to driver frustration, poor performance, downtime, expensive repairs, and increased emissions, low-quality fuel can impact many areas of fuel delivery and engine components to realize a loss of mpg, a loss that may otherwise be optimized if higher-quality gasoline is used. The least-expensive fuel at the pump may cost a mpg penalty and expensive repairs that, by comparison, more expensive fuel in the lowest grade possible is a more economical choice in the long run.

In the end, drivers should carefully examine the fuel requirements indicated in the owner’s manual and avoid wasting money on octane value the engine cannot use. In addition, drivers should seek to understand the additive and detergent packages contained in purchased fuel.

One last consideration: many fleets have begun examining and, in some cases, embracing extended lifecycling. Thus, vehicles are remaining in fleets longer, resulting in higher mileage on the engines and ultimately a stronger likelihood of repair or replacement due to wear and tear. While it is never too late to reverse the signs of aging, preventing damages and hostile environments in the fuel system and internal engine components is usually a sound practice.

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