엔진오일 교환 수리 사례

2026. 6. 30. 작업

난이도 & 준비물

증상

Why or why not increase engine efficiency by running the car "fuel-lean" (using a turbo or supercharger)?

처리 내용

Lean ≠ More Air I believe the source of the misunderstanding is in how the term "lean" is being interpreted. A lean mixture doesn't indicate the presence of more air. It indicates the presence of a higher proportion of air compared to fuel (air-fuel ratio, or AFR ). Quick example Mixture A has 1,000 g of air, 80 g of fuel. AFR = 1000/80 = 12.5 Mixture B has 100 g of air, 7 g of fuel. AFR = 100/7 = 14.3 Since 14.3 > 12.5, Mixture B is leaner than Mixture A, even though Mixture A has more air. This is why @cdunn is right ; the presence of a turbocharger or supercharger doesn't impact the ability of an appropriately-sized catalytic converter from doing its job. So why is it not good for cats to run lean? A catalytic converter is designed to scrub harmful gases out of exhaust gases. It does this through a chemical reaction that involves the presence of catalyst(s). The most popular type of cat design today is the three-way catalytic converter, which handles three types of harm