The Efficacy and Risks of Leaded Fuel in Modern Car Engines

While it is physically possible for a car engine to run on leaded fuel, the law now strictly prohibits its use. The primary risk lies in the catalytic converter, as lead can severely damage it.

The Engine's Perspective on Leaded Fuel

From an engine's standpoint, leaded fuel is not inherently detrimental. However, this is where the trouble begins. The main issue is the catalytic converter. Lead found in the fuel will poison the catalyst, leading to irreparable damage to the converter. This is a significant concern, as catalytic converters are now a standard feature in modern cars, particularly those produced from 1975 onwards.

A Brief History: Leaded Fuel and its Benefits

Leaded fuel, specifically tetraethyl lead, was once widely used in automotive gasoline. It served two crucial purposes: it elevated the octane rating, which is beneficial for performance and fuel efficiency, and it lubricated the valve seats, extending the life of the engine. The use of such fuel peaked around the early 1970s when it was mandated for nearly all vehicles.

The Transition to Unleaded Fuel

The shift from leaded to unleaded fuel began in earnest in 1975. As governments tightened emissions and fuel economy standards, the inclusion of a catalytic converter became mandatory. This change required exclusive use of unleaded fuel, which in turn necessitated hardened valves and valve seats to handle the absence of lead lubrication.

The Last Days of Leaded Fuel

Cars continued to run on leaded fuel until approximately 1992. I recall purchasing such fuel for my F-350 pickup truck until 1992; since then, no major fuel station has supplied leaded fuel. While historically leaded fuel contributed to elevated lead levels in soil near freeways, this issue is largely resolved. Currently, elevated lead levels are only found near certain private airports, and it is permissible for aircraft to use leaded fuel in 2024. For those running older vehicles with catalytic converters, using leaded fuel would quickly destroy the converter, rendering the car incapable of environmentally compliant operation.

Immediate Performance Enhancements with Leaded Fuel

Although the use of leaded fuel can improve engine performance, it comes with significant risks. Boosting turbo pressure or using higher compression pistons can lead to substantial horsepower gains. However, these enhancements are not without costs. For instance, a more advanced racing gasoline, such as 106 octane fuel, can be quite expensive, costing around eight dollars a gallon. Prioritizing public health and environmental well-being over the convenience of high-octane fuel might seem less ideal, given the potential long-term effects of lead exposure. Engaging in leaded fuel use can not only damage your car’s catalytic converter but also contribute to harmful health effects and environmental degradation.

Given these considerations, it is crucial to avoid leaded fuel for modern vehicles. The cost and risk associated with using such fuel far outweigh the benefits, particularly when there are sustainable alternatives available. Choosing unleaded fuel and ensuring your vehicle's components are compatible with it ensures both performance and long-term safety.