accusump valve selection

[MrBlah]

seeing consistent oil pressure drops on left hand turns, down to 25psi is concerning, even small turns like a chicago box will see a drop in pressure, and I'm on 200tw tires!!!!!! before I order a set of R7s I need to get this resolved

Installing a 2 or 3 quart accusump, there are two options.

Assumptions: Idle is 30-32 psi, on track psi is always over 80 except in high g left hand turns

20-25 psi switch, probably never trigger but is automatic
35-40 psi switch, must be enabled when I enter the track manually, will prevent deep dips
55-60 psi switch, must be enabled when I enter the track, should keep oil pressure graph flat

every dip in this log is a left hand turn, had +1 quart of oil in the pan

 

[shushikiary]

I have an accusump that is ready to go on my car as well and have had similar questions.

From what I can tell they tell you to pick a valve pressure based on your idle pressure, but I agree the 25 psi valve would only protect against catastrophically low oil pressure, but a higher PSI valve might not let the sump refill until you are at higher pressure.

From the graph you showed above it would seem that a good choice would be the 55-60 psi valve as it would stay filled thanks to the oil pressure almost always being above that except when it drops.

I agree though it's hard to tell which switch pressure you should get. I even called them on the phone and that answer was still not clear to me. It seems like there is no perfect solution.

If you pick a high pressure it really protects well while running it, but then it will just discharge its self when at idle, which means you will need to "recharge" its volume when you first go back to higher pressure.


I think maybe a better solution would be a double switch setup. One that only lets the sump drain if above a certain RPM and below a certain pressure, and then lets the sump fill if you're above a certain rpm and over that same pressure.

Here is Canton's article about it: http://blog.cantonracingproducts.com/blog/importance-of-accusump-valve-selection-how-to-choose

There they describe the idle problem, and why you want to pick a valve that is near idle pressure, but this means the sump won't dump it's oil until you're down to idle pressure, meaning it won't do anything for you with the pressures you're seeing in the corner as the idle pressure is pretty close to what you're seeing in the corner.

So yea, I'd really like to see an RPM switch as well, so you can set it to say 2k RPM, or what ever RPM you first see above 60 psi, then pick the 60 psi pressure switch and it will then not dump the sump at idle. Problem solved.


Hmm... I know the AIC 6 uses pin 21 (a black wire) for RPM from the E90 MSD80/1 ECU, but the REFLEX uses a true crank position sensor wire... so I suspect the wire used for the AIC 6 would allow one to hook up an RPM switch as it's likely a pulsed square wave for the tach.... Such as this one: https://www.summitracing.com/parts/izl-n3211

Then you could program the RPM of the switch and wire it in series with the pressure switch/manual switch and have the system I described.

 

[shushikiary]

I called Canton again and this time got some clearer details.

The EPC valve does indeed have a check valve in it. When the valve is off it has a one way check valve to allow oil into the sump. When it is on, oil can flow either direction. The pressure switch is normally closed, and only opens when the pressure goes above the stated pressure.

Thus if you took the RPM switch I gave above from summit, and wired it in series with the pressure switch, and got the 55-60 psi switch, you'd get the results you want. It wouldn't drain the sump at idle, and once you got above your set RPM and the pressure is bellow 55-60 it would open and the sump would dump oil to try to hold pressure until the pressure in the air/nitrogen side of the sump matches the oil pressure.

You can indeed just wait to turn the manual switch on until you're out on the track and know you'll be above idle speeds the whole time as well, then shut the switch off if you get down to idle or are off the track, that is also an option if you want to run the 55-60 psi pressure switch.