Why high octane gas

The only way to find out is to fill the tank with one of the premium fuels and try it, although such trials are somewhat subjective, being based on a 'seat of the pants' feel for the vehicle. Learn more. Become a part of Queensland's largest club and access a range of products, services and discounts. Contact us. Business Products Member benefits for business. Contact us Feedback and Complaints Find a store.

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Register here. Claims Weather event claim notification Home insurance claims Car insurance claims Pet insurance claims More Oh well. The Charger's manual says 87 octane will provide "satisfactory fuel economy and performance.

Similar to the BMW, the Dodge's gains on the dyno 14 horsepower and 23 lb-ft of torque translated into negligible improvement in our real-world acceleration testing. Saddled with elephantine heft and eager to spin its rear all-season tires at launch, the Charger posted the same 4. At triple-digit speeds, the higher power on 93 octane gave the Charger an advantage measured in tenths of a second.

The Dodge also posted a 0. Just as important, the bellicose roar of the iron-block Hemi and the Charger's ability to reduce its rear tires to jungle-gym ground cover are unaffected by the fuel in the tank.

While Ford's EcoBoost F stands out as an obvious exception, the Dodge Charger's numbers make for a tidy summary of our findings. If you buy fuel with an octane rating above the manufacturer's requirement, you're likely to feel it in your wallet more than the seat of your pants. How your engine constantly invites and silences engine knock to estimate a fuel's octane rating. Your car doesn't know the octane rating of the fuel in its tank.

Instead, the engine controller calculates an inferred octane with closed-loop logic that continuously advances the ignition timing until it detects knock, which occurs when a portion of the fuel-air mixture ignites before the spark-plug-initiated flame front reaches it.

The further the computer can advance the timing without provoking knock, the higher the octane rating. During knock, the flame front travels through the combustion chamber up to 10 times quicker than the normal spark-initiated flame front. Left unchecked, these pressure waves can damage the head gasket, pistons, or cylinder head.

But the occasional brief knock is a useful tool for checking that the engine is operating efficiently. It's detected with one or more knock sensors bolted to the block to sense the oscillations created by the pressure waves with a typical frequency between 7 and 16 kilohertz. Stephen Russ, senior technical leader for gas engines at Ford, says this normal knock is usually detected and addressed within one or two combustion cycles and poses no threat to the engine.

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You may be able to find more information about this and similar content at piano. Advertisement - Continue Reading Below. More From Features. The refining industry invested in additional refining capacity to replace lead with BTEX, a high-octane petroleum refining product.

As a result of its substitution for lead, BTEX volume rose from 22 percent to roughly a third of the gasoline pool by In premium gasoline grades, the BTEX volume content was as high as 50 percent. In mandating cleaner fuels, through reformulated gasoline and other programs, EPA has reduced the volume of aromatics to between 25 to 28 percent of the conventional gasoline pool, though some health professionals question the safety of even these levels.

After the lead phase-out, there were early concerns regarding the BTEX complex. Today, health research indeed suggests that even very low-level exposure to the BTEX complex, from gasoline additives and other petroleum products, may contribute to negative developmental, reproductive and immunological responses, as well as cardio-pulmonary effects.

Upon incomplete combustion of the BTEX complex contained in gasoline, ultra-fine particulates UFP and polycyclic aromatic hydrocarbons PAHs are formed, which carry their own adverse health impacts even at low levels. Both UFP and PAHs have also been linked to developmental and neurodegenerative disorders, cancers, and cardio-pulmonary effects.

Considerable attention has been given to benzene in fuel, as it is highly toxic. At the same time, the partial replacement of benzene with other aromatic compounds xylene, ethyl-benzene, toluene may not be sufficient in reducing exposure to BTEX's toxic effects.

The other aromatics, such as toluene and xylene, are not capped. Early automakers expressed interest in plant-based alcohol fuels, such as ethanol. Henry Ford designed the first Model T to run on ethanol. But, at the time, gasoline was a much cheaper fuel. During the oil embargo, regular unleaded gasoline prices jumped 57 percent and routine gasoline shortages also occurred.

These events, and the regulation of many air pollutants, sparked a renewed interest in fuel efficiency, electric vehicles, and renewable fuels such as ethanol, which were seen as ways to meet the new regulations and reduce petroleum consumption.

Today, the majority of ethanol in the United States is blended with gasoline to produce E10 10 percent ethanol, 90 percent gasoline. Over 95 percent of gasoline sold in the United States is E In addition to having lower lifecycle greenhouse gas emissions than conventional gasoline, ethanol is an excellent octane provider, with neat pure ethanol having an octane rating of over Ethanol, which is generally the cheapest octane provider, is then used to bring the octane rating of the gasoline up to the labelled octane value on the gas pump.

For example, 84 octane gasoline is typically blended with 10 percent ethanol to reach the minimum octane requirement of 87 for retail gasoline. Currently, there are two ways of increasing the octane content of gasoline: increasing the volume of gasoline aromatics or increasing the volume of ethanol. While ethanol has a higher volatility than gasoline, meaning it vaporizes more quickly, it is a cleaner-burning alternative to petroleum-based octane boosters.

Additionally, the toxicity of ethanol is low compared to the health effects of BTEX and its combustion products, such as ultrafine particulates UFPs and polycyclic aromatic hydrocarbons PAHs. A modest increase of ethanol content in fuel from 10 to 15 percent would result in an anticipated 6. There is contradictory evidence that increasing ethanol content in gasoline increases nitrous oxide NOX emissions, an ozone precursor.

Several studies find either no relationship between ethanol blending and NOX emissions, or find decreased NOX emissions with increasing ethanol volumes. Other studies suggest older cars emit more NOX when using ethanol blends.

However, a study of make and model year vehicles found no increase in NOX emissions between E10, E15 and E20 blends, suggesting that both engine design and engine age play a role in NOX emissions. Overall, the effect of ethanol on NOX and carbon monoxide CO emissions is minor in newer engine emission control systems. RFS sets a minimum volume of renewable biofuels to be blended into the transportation fuel supply.