Accusump Operation

[wizzo]

Hey everyone, just have a question that i hope someone can answer and make more clear.

I have done a lot of reading regarding accusump systems, and i cant wrap my head around the operation of the accusump.

In terms of priming and pressurizing the block on start up, all makes sense.

However in a scenario such as a long high G turn were you have a drop in oil pressure due to windage, what triggers the accusump to automatically pump oil into the engines galleys at that instant. Because in that case, what if i am driving along a highway with oil pressure at 60psi and suddenly put the clutch in and oil pressure dropped, would the accusump suddenly pump oil for example?

Does anyone see what is confusing me? It is the operation while on a track.

[zypher]

The accusump operates like an electrical capacitor but for fluid.

Basically it will build pressure in a reserve volume say 3qts. So if your engine makes 90psi max oil pressure ideally it will store 3qts of oil at 90psi.

When the pressure in the system drops below the pressure in the accusump then that oil is injected into the system.

[wizzo]

Thats what i thought, so, considering oil as incompressible, it will always store 3 qts of oil and the pressure the oil is stored at is what varies.

When ever the oil pressure in the engine drops, it will pump oil to bring pressure in the engine back up?

Originally Posted by zypher

The accusump operates like an electrical capacitor but for fluid.

Basically it will build pressure in a reserve volume say 3qts. So if your engine makes 90psi max oil pressure ideally it will store 3qts of oil at 90psi.

When the pressure in the system drops below the pressure in the accusump then that oil is injected into the system.

[Gear_One_Performance]

There is a piston that separates your charge (that you set with a compressor and chuck) and the oil, when the oil pressure drops the compressed air here pushes the piston and forces the oil into your engine.

[justatroll]

Accusump operation is a little more complicated than even many of the guys that use them at the track appreciate.
First there are two setups:

Manual valve only - In this configuration the manual valve is open the entire time the engine is running. As engine oil pressure rises and falls the accusump discharges and recharges constantly. This will help with cases of oil starvation typically experienced during long high G cornering where oil moves away from the oil pickup and air is ingested into the system. In this configuration it is critical to remember to close the valve before shutting down the engine, or the accusump will discharge its contents and over fill (potentially) the engine sump.

Electric valve with pressure sensor - In this configuration there is an electric valve in place of (or in addition to) the manual valve and has a pressure sensor that is set to some low value below the engine standard operating point. If the engine runs at a low of ~30 PSI, then select a sensor that opens the valve at say ~20 PSI. So with the type of valve used (Moroso or Canton) it will allow oil to flow from the engine side to the accusump side even when the valve is closed. This allows the accusump to recharge when the engine oil pressure is above the valve setpoint. However it will not discharge until the engine oil pressure drops below the pressure setpoint. If the power to this valve comes from the ignition power, then it will close when the engine shuts off (assuming it was shut off by turning off the ignition and not stalling)

Some people believe that an accusump will save the engine in the case of a catastrophic failure (e.g. An oil cooler rupture) however this may not be the case depending on how the system is setup.
If you were to blow an oil cooler, and the accusump begins to discharge and keep the engine oil pressure up, then any Low Pressure Dash Indicator might NOT indicate a problem until AFTER the accusump is depleted. In this case the only thing that the accusump did is give you an extra 3 quarts of oil to dump on the track before the driver gets notified. This is becuse the accusump just masked the failure until it was depleted.

So there is some debate about what is the best way to operate an accusump. Do you drive with the manual valve closed until a low pressure condition is detected by the driver (dash light comes on), THEN the driver can open the valve while getting the car pulled over?

It is also critical how the accusump (AS) is plumbed into the system.
If one were to plumb the AS into the oil cooler loop, and an oil cooler failure is the most likely scenario, then IF the cooler blows, all of the AS oil goes straight to the ground and none makes it into the engine.

So the best way is to plumb the AS is directly into the engine oil galley(s) that feed directly to the bearings. If this is not possible, then a one-way check valve can be used to direct the AS oil into the engine and not back out towards the failure.

For my system, I have a manual valve and an electric solenoid valve with an adjustable pressure sensor connected to the engine supply line. I also connected a bright red dash indicator to the solenoid valve so that I can see when the accusump is discharging. This is because the accusump might begin discharging and the main Low Oil Pressure Indicator on the dash would NOT turn on since the AS is keeping the pressure up.

The idea is that The low oil pressure light might not come on until the AS has discharged fully.

[LS1M]

It's a cylinder with a plunger in it. The cylinder is filled with air. When you start the car, the oil enters the cylinder on the other side of the plunger and pushes it against the air, compressing it until they're at the same psi. So, if you have a 3-quart cylinder with 15 psi of air, then your start the car & oil pressure goes up to 30 psi, you end up with 1.5 quarts of oil in the accusump (the air is compressed to 30psi and occupies half the space). When the car stops, or you have an oil pressure system failure, the air pressure will push the plunger out until the pressures equalize again: if the oil pressure is zero, the plunger will go all the way back, 15 psi air pressure and zero oil in the accusump.


That's a great idea and I used one on my V8 Camaro and I loved it. I'm not so sure it would work on an FA20. The problem is the incredible variation in oil pressure. My car runs 0w30 and is over 100 psi cold, then maybe 20 hot. So if I have an accusump at 20 psi pre-charge, then when I start the car, there's going to be a ton of oil in it and not much air. When I'm idling, the oil pressure goes down, the accusump empties out & now there's not much oil in it. As the revs go up & down, the oil plunger goes in & out, and I end up with a wild variation in the oil level in the pan. It may overfill, or it may not be there when I need it, especially if I have the electric solenoid, which dumps quickly but recharges slowly. This was not an issue with my Camaro, which had a rock-solid oil pressure of 45; I could leave the valve open all day & knew it had plenty of reserve capacity for the next track run or curve or whatever.


I think the only way to get a good use out of the accusump on our cars would be to build a control circuit for it. You'd have to measure pressure-per-1000-rpm's, and only open the valve if it falls below the set value. So, you're at 5000 rpm's and 50 psi, you're OK, but if your pressure falls to 40 psi, the valve opens up & maintains pressure. The accusump is just in standby mode all the time then, filled with 100+ PSI of oil so it's got plenty of charge to handle a wide turn or fast takeoff. Plus, you can set the oil pan level with a fully charged accusump & not worry about an over-fill. And you'd have to put the oil pressure sensor upstream of the sump, so you're measuring oil pressure off of the oil pump, not the pressure coming straight out of the accusump.


-Mark

[LS1M]

^^^ beat me to it lol!

[Canton Racing Products]

A lot of good information on this thread about the Accusump. The best way we have found to explain the Accusump is that it is storing pressure off of the oil pump. Imagine the oil pump pushing against the Accusump piston. Once the oil pump is no longer applying pressure in the Accusump the oil that was pushed in to the Accusump is going to come out because it isn't being pushed in anymore.

In road racing situations we always recommend using the pressure switch activated electric valves. They act as one way valves when they are off so they will still store oil and pressure up until your oil pressure drops below the trigger pressure. Then the Accusump will discharge. Part of the single pressure range switch is finding one that is high enough to trigger quickly but not above the idle oil pressure causing it to discharge when you are at idle. This can be solved by just leaving the valve off until you are hot lapping but a lot of guys don't like to have to remember to do that before starting. What we have seen people do is get creative and link either the gas pedal or the transmission to the valve. Either turning the valve on only when the gas pedal is pressed or only activating the valve in 2nd gear or higher. Last year we did a private label Accusump for APR motorsports and they actually programmed the VW CAN BUS system to only trigger above a certain RPM range.

As for the cooler bursting scenario. We are starting to recommend wiring in an LED light to the valve so you can see when the Accusump is actually discharging. This way in the cooler burst scenario you would see the light staying on for a long period most likely in a situation that the Accusump shouldn't be discharging and have time to stop before doing any damage. This actually happened with one of our NSX customers. He smashed his oil pan and continued driving until he noticed that the Accusump valve trigger light didn't turn off. Saved his motor and probably his racing season as those engines are not cheap.

The other reason that we are suggesting the LED light is because you can also see the shortcomings of your oiling system without doing damage to the engine. You can drive and see when the Accusump is picking up the slack and make changes accordingly, or just know the Accusump is working.

I will try to check back in this post but if anyone has any direct questions feel free to email them (info@cantonracingproducts.com)

[crazyfrenchbiker]

Which EPC do you think would be suitable for our platform? I was going to just get a manual valve, but it sounds like an electric valve would be much better suited.

[wizzo]

This is all awesome info!

Think the idea of connecting it with rpm would be great, and just have it activate at the track at an rpm over 2500 rpm

[Canton Racing Products]

Originally Posted by crazyfrenchbiker

Which EPC do you think would be suitable for our platform? I was going to just get a manual valve, but it sounds like an electric valve would be much better suited.

I don't have any experience with the FA20 motor yet but if you could give me hot idle oil pressure and normal operating oil pressure I can definitely recommend the right valve.

[justatroll]

Originally Posted by wizzo

This is all awesome info!

Think the idea of connecting it with rpm would be great, and just have it activate at the track at an rpm over 2500 rpm

I have an ardunio datalogger that reads my RPMs from the ignition coil (vintage racecar) I could easily program that to provide my accusump power and "inhibit" whenever the RPMs are below a set value.
That would alleviate my concern about shutting off the engine but leaving the AS power enabled (like turning off the IGN switch instead of the MAIN)

In fact with the tiny arduino sitting right in front of me (known as a beetle) I could make the whole thing fit in a case about the size of a car power relay. It would just need +5V power and a TACH signal.

[Calum]

Originally Posted by justatroll

I have an ardunio datalogger that reads my RPMs from the ignition coil (vintage racecar) I could easily program that to provide my accusump power and "inhibit" whenever the RPMs are below a set value.
That would alleviate my concern about shutting off the engine but leaving the AS power enabled (like turning off the IGN switch instead of the MAIN)

In fact with the tiny arduino sitting right in front of me (known as a beetle) I could make the whole thing fit in a case about the size of a car power relay. It would just need +5V power and a TACH signal.

That would likely work well, though a window switch might be a better option for those that don't have an arduino.

http://www.summitracing.com/int/sear...-rpm-activated

[crazyfrenchbiker]

Originally Posted by Canton Racing Products

I don't have any experience with the FA20 motor yet but if you could give me hot idle oil pressure and normal operating oil pressure I can definitely recommend the right valve.

From another members findings, as I haven't been monitoring pressure yet but will be building my motor with the upgraded oil pump gear. I would say the goal is to be at 70-90 PSI all the time on the track.


STREET TEMPS
0W20 Redline

0w20 Redline 185F @ 800RPM 10PSI Oil Pressure
0w20 Redline 185F @ 2000RPM 35PSI Oil Pressure
0w20 Redline 185F @ 4000RPM 54PSI Oil Pressure
0w20 Redline 185F @ 7000RPM 65PSI Oil Pressure

10W30 Redline

10w30 Redline 185F @ 800RPM 19PSI Oil Pressure
10w30 Redline 185F @ 2000RPM 51PSI Oil Pressure
10w30 Redline 185F @ 4000RPM 65PSI Oil Pressure
10w30 Redline 185F @ 7000RPM 83PSI Oil Pressure

10W40 Redline

10w40 Redline 185F @ 800RPM 25PSI Oil Pressure
10w40 Redline 185F @ 2000RPM 64PSI Oil Pressure
10w40 Redline 185F @ 4000RPM 78PSI Oil Pressure
10w40 Redline 185F @ 7000RPM 91PSI Oil Pressure


TRACK TEMPS AFTER 9 LAPS @ 1 Minute 15 Seconds Per Lap
0W20 Redline

0w20 Redline 225F @ 800RPM 7PSI Oil Pressure
0w20 Redline 225F @ 2000RPM 30PSI Oil Pressure
0w20 Redline 225F @ 4000RPM 48PSI Oil Pressure
0w20 Redline 225F @ 7000RPM 43PSI Oil Pressure


10W30 Redline

10w30 Redline 245F @ 800RPM 7PSI Oil Pressure
10w30 Redline 245F @ 2000RPM 35PSI Oil Pressure
10w30 Redline 245F @ 4000RPM 52PSI Oil Pressure
10w30 Redline 245F @ 7000RPM 46PSI Oil Pressure

10W40 Redline (12 Laps)

10w40 Redline 265F @ 800RPM 8PSI Oil Pressure
10w40 Redline 265F @ 2000RPM 31PSI Oil Pressure
10w40 Redline 265F @ 4000RPM 55PSI Oil Pressure
10w40 Redline 265F @ 7000RPM 45PSI Oil Pressure[/QUOTE]