Suzuki Advanced Cooling System
The Suzuki Advanced Cooling System (SACS) was created in the early 1980s by engineer Etsuo Yokouchi. It was first used on the GSX-R sport bikes from 1985 to 1992, and later on the Bandit (GSF) and GSX lines until 2006, as well as the DR650 from 1990 to today. Engines with SACS are known for durability. The system was developed to solve reliability problems on Suzuki’s turbo XN85 and drew inspiration from WWII aircraft cooling, which used oil jets to cool piston tops. When Suzuki started the GSX-R, they aimed for about 100 hp from a 750cc engine and found air cooling alone wouldn’t be enough, so SACS was added and carried into larger GSX-Rs. The last GSX-R to use SACS was the GSX-R1100 in 1992; later models moved to water cooling. How it works: a large flow of engine oil is directed to hot areas like the top of the combustion chamber to carry away heat. To supply oil for both lubrication and cooling, SACS uses a two-chamber oil pump: a high-pressure side for lubrication of the crankshaft, bearings and valvetrain, and a high-volume, low-pressure side for the cooling and filtering circuit. The oil passes through the filter, then a cooler, and back to the sump after removing heat from the engine.
This page was last edited on 2 February 2026, at 12:53 (CET).