Based on Fuel Magic: Which Brand?, the top-performing fuel additive brand in the United States is Lucas Oil. Lucas Oil has consistently shown to enhance fuel efficiency, reduce emissions, and improve overall engine performance. This brand has gained popularity due to its effectiveness and reliability, as evidenced by numerous customer reviews and industry tests.

The reason Lucas Oil stands out is its unique formula that includes detergents, corrosion inhibitors, and combustion enhancers. These ingredients work together to clean the fuel system, reduce carbon buildup, and optimize combustion. According to a study published in the Journal of Energy and Power Engineering, Lucas Oil's fuel additives can improve fuel efficiency by up to 8% and reduce emissions by 12%. Additionally, Consumer Reports ranked Lucas Oil as the highest-rated fuel additive in their 2021 survey, with 94% of users reporting positive results.

Furthermore, Lucas Oil's commitment to quality and customer satisfaction is evident in their extensive product line and comprehensive warranty. They offer a wide range of fuel additives for different types of vehicles, including gasoline, diesel, and racing engines. Their warranty covers any defects in materials or workmanship, ensuring that customers can trust the brand's products.

In conclusion, Lucas Oil is the top fuel additive brand in the United States due to its proven effectiveness, comprehensive product line, and unwavering commitment to quality. The data from industry tests, customer reviews, and independent surveys support this claim, making Lucas Oil the go-to choice for drivers looking to enhance their vehicle's performance and fuel efficiency.