Oil Accumulator

[blsfrs]

I am by no means an expert on this subject, but I have tried to exercise due diligence. I installed a 2qt accumulator on my car as per instruction from Element Tuning on my initial engine build. As it is now, I have a manual valve that I open when I go on track and close when I come off. Most of the time I actually remember to do this. (It's an item on my check list).

My car is na. Tein coilovers, 200tw tires. I run DE2 now but plan to move to DE 3 later this season. My car pulled 197 hp and 163 ft lbs on PTuning's dyno. My primary tracks are VIR and Summit Point.

Recently, I have read the comments in the Gen 2 section that call into question the benefit of accumulators. With that in mind, I contacted Phil Grabow and had a bit of a discussion. He was very generous with his time and expertise. Based on his testing and experience, he recommends using the accumulator and using it without a low pressure switch. He described it as a poor man's dry sump.

Here's my set up.

[NoHaveMSG]

What pressure do you have it set at?

[KillerBMotorsport]

Originally Posted by blsfrs

Based on his testing and experience, he recommends using the accumulator and using it without a low pressure switch. He described it as a poor man's dry sump.

Can he share the before/after data?

Calling it a poor man's dry sump is misleading. A poor man's dry sump would be a 2-stage pumping back into the sump (like on the newer 911 Carrera) vs a proper 5-stage with a remote reservoir (911 GT cars).

[KillerBMotorsport]

Originally Posted by NoHaveMSG

What pressure do you have it set at?

This is a manual setup, there is no valve. On track it's open all the time.

[NoHaveMSG]

Originally Posted by KillerBMotorsport

This is a manual setup, there is no valve. On track it's open all the time.

I thought you still had to set a precharge pressure.

[KillerBMotorsport]

Originally Posted by NoHaveMSG

I thought you still had to set a precharge pressure.

The 'spring' pressure that returns the oil, needs to be charged with air, but that is a set once and forget. Essentially, it's the spring on the other side of the accumulator's plunger.

With how BLSFRS is running it, it's open. This is more like a dampener that takes down high rapid spikes and low rapid drops. So if you are in a condition and your pressure goes from 60psi to 2psi, the plunger will start pushing oil back, at 60psi. Of course, as the conditions continues beyond a microsecond and the accumulator piston starts to move, it's pressure drops. Just as an example say you have that 2psi for 5 seconds, at 0 seconds, it's 60psi in the accusump, and 1 second elapsed it may be 40psi, and 2 seconds, 20psi. You can actually calculate how much oil the accumulator holds and what the time/pressure output plot looks like. Once we have flow data, you can make some rough worst case calculations.

With an electronically valved setup, you can fill the accumulator at your peak pressure (or whatever peak pressure you set it to) and then set a minimum value, where the accumulator backflows into the oiling system, say if it dropped below 40. This method gives a bigger pressure delta, which means the accumulator has more volume of oil to push when there is a pressure drop. Plus, it won't continuously recharge, it only recharges once you're over a preset value.

[blsfrs]

I had been running a precharge of 7psi as recommended by Canton. Phil recommended 12psi.

I see part of Killer B's point, except that an open valve should prevent significant oil pressure drops by constantly feeding oil to the system. This does have and end point but, hopefully, by that time, you are out of the situation that caused the oil to slosh away from your pickup and your engine can start sucking oil again.

A problem that I see with running an electronic valve is that the accusump opens only when the engine has reached a preset low pressure. As Killer B stated there is a bigger delta so there is a bigger discharge and bigger recovery that takes oil away from the engine.

Phil might have specific data to back up his recommendations but I suspect that he did things to prevent his engines from going boom.

I think that we all know that the Accsump is not a completely perfect solution but it's a lot cheaper than a dry sump.

[pope]

You can get a switch activated electric valve instead of the lever. Still operates the as strictly open or closed (although it will allow recharge when closed, unlike the manual lever), but doesn’t require mounting and routing a push/pull cable.

Electric valve also allows for getting fancy with computer integration to vary opening threshold according to conditions.

One of these days I should really do something with the accumulator I’ve had sitting in my basement for like 13 years.

[blsfrs]

Originally Posted by pope

You can get a switch activated electric valve instead of the lever. Still operates the as strictly open or closed (although it will allow recharge when closed, unlike the manual lever), but doesn’t require mounting and routing a push/pull cable.

Electric valve also allows for getting fancy with computer integration to vary opening threshold according to conditions.

One of these days I should really do something with the accumulator I’ve had sitting in my basement for like 13 years.

I tried 3 electronic valves. One (from Canton) burnt out and 2 (from Moroso) leaked.

[NoHaveMSG]

Originally Posted by blsfrs

I had been running a precharge of 7psi as recommended by Canton. Phil recommended 12psi.

I see part of Killer B's point, except that an open valve should prevent significant oil pressure drops by constantly feeding oil to the system. This does have and end point but, hopefully, by that time, you are out of the situation that caused the oil to slosh away from your pickup and your engine can start sucking oil again.

A problem that I see with running an electronic valve is that the accusump opens only when the engine has reached a preset low pressure. As Killer B stated there is a bigger delta so there is a bigger discharge and bigger recovery that takes oil away from the engine.

Phil might have specific data to back up his recommendations but I suspect that he did things to prevent his engines from going boom.

I think that we all know that the Accsump is not a completely perfect solution but it's a lot cheaper than a dry sump.

Thanks, I was wondering since I had seen people on other platforms recommend a wide range, from 5-25psi, which is well beyond the range Canton recommends. So I was curious what you were running and how you settled on the number.

[KillerBMotorsport]

Would be interesting to see how much oil goes into it when it's charged. Would be easy for the pope since he has one sitting in the basement.

[blsfrs]

Originally Posted by KillerBMotorsport

Would be interesting to see how much oil goes into it when it's charged. Would be easy for the pope since he has one sitting in the basement.

P1V1=P2V2 anyone? Oh Boyle!!!

[pope]

Originally Posted by blsfrs

I tried 3 electronic valves. One (from Canton) burnt out and 2 (from Moroso) leaked.

That’s some bad luck. My valve is from Moroso and ran on a car for 7 years without issue.

[NoHaveMSG]

Well I have a 2 qt on the way. I'll source the valve and hose separately. Not sure why I haven't gone this route before, I had looked into it before but don't know why I didn't follow through.