5. Mazda RX-7 (Rotary Engine)
The Mazda RX-7, introduced in 1978, popularized the Wankel rotary engine, offering smooth power delivery and a lightweight design. Despite its performance, the rotary engine faced challenges such as apex seal wear, leading to decreased performance and reliability. (autos.yahoo.com) Additionally, the engine’s higher oil consumption and emissions issues limited its appeal in markets with stringent environmental regulations. (hydrogenfuelnews.com) As a result, the RX-7’s rotary engine remains a niche curiosity among automotive enthusiasts. (hagerty.com)