Taxicab field tests of modern motor oil detergent packages showed a substantial improvement in deposit control compared to metallic sulfonate-phenate motor oils. Those containing metallic detergents, with or without supplemental ashless detergents, were less effective than ashless detergent oils. Ashless detergents provide the bonus benefits of reduced octane requirement, surface ignition, and valve and piston failures associated with metallic detergent ash.
The L-43 CLR Engine Test Technique did a good job of predicting performance in severe stop-and-go service with a wide variety of today's motor oil detergents.
