CLASS RACER FORUM - View Single Post - Accusump

JGrossijr · 01-06-2024, 01:30 PM

One consideration regarding accumulator volume selection is that capacity does not necessarily, and in my experience never does, equal actual working volume. Engine oil pressure, valving, and accumulator air pressure will determine how much oil is actually held in the accumulator.

The higher the oil pressure the more oil that can be stored in the accumulator up to capacity
The more air in the accumulator the less oil that will be stored in the accumulator
In simple open or closed valving (mechanical or electric) the oil volume in the accumulator, and in the engine sump, will vary.

In my opinion Mike Mans nailed the best reason for an accumulator. You end with the ability to pre-lube the engine on every start-up, whether its been 5 minutes or 5 months. This is particularly important on an engine like an LS with a front-mount above sump oil pump.
Secondly the accumulator acts as an insurance should the oil pressure drop for whatever reason. This can be particularly important in those circumstances where you find yourself draining oil to a minimum level for that go-fast run.

Don't simply plumb an accumulator into your oil system and assume it is holding the advertised capacity. Doing so will like result in more oil than you want in the sump, and more windage. After you install the system run the engine up to maximum oil pressure, close the valve, and shut the engine off. Disconnect the oil line and discharge the accumulator to determine what the maximum amount of storage actually is in your application. Try this with different amounts of air in the accumulator and determine what the ideal amount of air pressure is for your application. This will help you determine how much extra oil to add to your system. Keep in mind this volume will change as oil pressure changes in a simple open/closed valving, therefore engine oil level will vary proportionally to oil pressure.

This is where the Canton EPC valve
really shines. When the valve is closed it continues to fill and only discharges when pressure falls below a preset point. The preset point can be controlled with a mechanical pressure switch as supplied, or from a programmable switch output from your ECU. In this scenario there won't any oil being pushed into the engine until pressure drops below your pre-set, and the maximum amount of oil will be stored in the accumulator at all times above the preset. The preset point is generally just below idle pressure. In this case as the engine goes through higher pressures at higher rpm you push more oil into the accumulator. After a burnout, or any other significant rise in rpm the accumulator will be as full as it's going to get, and it will hold that volume until pressure falls below the preset. Should a condition arise where oil pressure drops below the preset the accumulator is as full as it can be with the most pressure possible, so response is quick with good duration. You would be amazed the differences in discharge at different holding pressures.

FWIW - The most oil I have been able to get into a 3 qt. Moroso accumulator at 90 psi was 2.5 qts.

01-06-2024, 01:30 PM	#8
JGrossijr Junior Member Join Date: Nov 2001 Location: Brentwood, California Posts: 98 Likes: 377 Liked 460 Times in 59 Posts	Re: Accusump - pros & cons One consideration regarding accumulator volume selection is that capacity does not necessarily, and in my experience never does, equal actual working volume. Engine oil pressure, valving, and accumulator air pressure will determine how much oil is actually held in the accumulator. The higher the oil pressure the more oil that can be stored in the accumulator up to capacity The more air in the accumulator the less oil that will be stored in the accumulator In simple open or closed valving (mechanical or electric) the oil volume in the accumulator, and in the engine sump, will vary. In my opinion Mike Mans nailed the best reason for an accumulator. You end with the ability to pre-lube the engine on every start-up, whether its been 5 minutes or 5 months. This is particularly important on an engine like an LS with a front-mount above sump oil pump. Secondly the accumulator acts as an insurance should the oil pressure drop for whatever reason. This can be particularly important in those circumstances where you find yourself draining oil to a minimum level for that go-fast run. Don't simply plumb an accumulator into your oil system and assume it is holding the advertised capacity. Doing so will like result in more oil than you want in the sump, and more windage. After you install the system run the engine up to maximum oil pressure, close the valve, and shut the engine off. Disconnect the oil line and discharge the accumulator to determine what the maximum amount of storage actually is in your application. Try this with different amounts of air in the accumulator and determine what the ideal amount of air pressure is for your application. This will help you determine how much extra oil to add to your system. Keep in mind this volume will change as oil pressure changes in a simple open/closed valving, therefore engine oil level will vary proportionally to oil pressure. This is where the Canton EPC valve really shines. When the valve is closed it continues to fill and only discharges when pressure falls below a preset point. The preset point can be controlled with a mechanical pressure switch as supplied, or from a programmable switch output from your ECU. In this scenario there won't any oil being pushed into the engine until pressure drops below your pre-set, and the maximum amount of oil will be stored in the accumulator at all times above the preset. The preset point is generally just below idle pressure. In this case as the engine goes through higher pressures at higher rpm you push more oil into the accumulator. After a burnout, or any other significant rise in rpm the accumulator will be as full as it's going to get, and it will hold that volume until pressure falls below the preset. Should a condition arise where oil pressure drops below the preset the accumulator is as full as it can be with the most pressure possible, so response is quick with good duration. You would be amazed the differences in discharge at different holding pressures. FWIW - The most oil I have been able to get into a 3 qt. Moroso accumulator at 90 psi was 2.5 qts.