Honda S2000 Tuning - Accusump And Vented Catch Can Install

Project S2K
Oil starvation is a serious issue and has claimed the life of many high-performance engines. While most production oiling systems are perfectly adequate for around-town use on street tires, oil-supply issues often arise on a racetrack with sticky DOT competition tires or slicks. This is because as lateral acceleration or g-forces increase, the unconstrained engine oil moves to the edges of the oil pan and away from the pickup. It only takes a fraction of a second with a dry oil pickup to cause bearing damage and engine failure.

There are several methods to prevent this all-too-common form of engine death. The most effective method for purpose-built race cars is called a dry sump system. A dry sump setup uses a multi-stage external oil pump to pull vacuum on a low-profile oil pan and then feed pressurized oil from an external oil tank back to the engine. While this is the most effective solution, it's also the most complicated and costly at $11,800 for the complete Toda kit.

The S2000 uses what's known as a wet sump system, which is standard on all but the most high-performance and exotic production cars. With a wet sump, the engine oil is stored in the oil pan and a conventional pickup supplies fluid to the oil pump. Wet sump systems can be made to work in high lateral g-force situations with the use of a baffled oil pan and an Accusump. A properly designed baffled pan uses trap doors and shelves to restrict oil flow away from the pickup, ensuring a constant supply of oil to the pump and bearings. However, in longer corners with sustained high lateral g-forces, the oil can still migrate away from the pickup. This is where an Accusump can save your engine.

Adding an Accusump system is an excellent way to ensure your engine maintains oil pressure during high-cornering loads.

Adding an Accusump system is an excellent way to ensure your engine maintains oil pressure

An Accusump is an aluminum cylinder with a piston installed. On one side of the piston, there's compressed air; on the other side, there's engine oil. When the engine is running correctly, oil pressure displaces the Accusump's piston and fills the cylinder with engine oil. Should the engine encounter a moment of low oil pressure - for example, during a high-speed corner that starts to force oil in the pan away from the pickup - the piston will expel the oil and in the process provide the engine with the necessary pressurized oil to avoid catastrophe. Once the low-pressure moment has passed (e.g. you're on a straightaway and the oil pickup has plenty of supply), the Accusump will refill with oil so that it's ready to spring into action the next time a sudden drop in oil pressure occurs.

With an Accusump there are several configurations that can be used. You can order the cylinder in 1-, 2- or 3-quart capacities with either manual or electric valves. The manual valve simply requires the user to open the valve before starting the engine and to shut the valve before turning the engine off (preferably at maximum oil pressure to fill the cylinder). This process effectively "pre-oils" the engine by providing a pressurized charge of oil prior to cranking, which helps to eliminate bearing wear at cold start-up. The electric valve allows for a more remote mounting and uses a toggle switch to actuate it. However, the solenoid actuated electric valve is slightly more restrictive than the manual ball valve, and therefore has a lower flow rate when a low-oil-pressure situation arises.

There's actually one other way to configure an Accusump that provides the best of both worlds: high flow and remote mounting. By using Accusump's EPC system, the same solenoid actuated valve is triggered by an oil pressure sending unit. When oil pressure falls below a selected point (55 psi for our application), the valve opens. When oil pressure is restored (above 60 psi), the valve closes. However, the valve will always flow toward the Accusump even when closed, so anytime the engine is operating above 55 psi of oil pressure, the Accusump is being charged. The EPC system achieves higher flow because the cylinder is fully charged with the air chamber at max pressure when called upon.