Accusump install

[bbnks2]

Originally Posted by rac

My 2c's on general discussion;
- wet sump systems are never perfect,
- a lot of racing classes have wet sumps mandated and live with oil pressure dips for many racing seasons without failure.
- bearing failure is a function of both rpm and load
- the minimum requirement for oil pressure would be a function of rpm, load and bearing surface area.

these engines are capable of producing high loads at low rpm hence oem design of the oil pressure curve rapid ramp up.

my advice to anyone logging oil pressure would be to plot their track data against both rpm and load. if the dips are only at high lateral g's with low engine load but still > 10psi per 1000rpm i wouldn't waste your time resources solving it. if the dips persist as you load up the engine and go full throttle on corner exit then that might be something to specifically target. this is were electronic control of the accumulated oil with say both rpm and tps as inputs could be useful in making the best use of a limited volume of oil.

alternatively if you really wanted to re-create the oem pressure v rpm curve i guess you could program a solenoid with that curve minus a practical trigger margin and just keep adding accumulators until there are no more significant dips past the trigger margin....

An accumulator is a very simple installation and relatively affordable. If you're doing this type of driving it's really a "might as well install one" type thing imo.

It's true, a hiccup of air at the pickup tube isn't going to instantly seize an engine... but that sudden drop in pressure surely is doing damage over time and a $400 device can minimize that damage or even save your engine in the event of an oiling failure on track. Does everyone need one? No. Plenty of people track their cars for years without issue. But if you're willing to drop 10k in mods to make it a "race car" then this should be one of those mods lol.

Check out this log:
https://datazap.me/u/mkilgore/ncm-su...3447-3447-4470

And I have logged and posted similar logs. Timestamp 1474 he is back on throttle with rpm and boost rising over 3,000rpm (engine is loaded) and oil pressure is continuing to drop. I know on a dyno my n55 PWG car made as much as 507wtq on the stock turbo at 27xxrpm. He's not at 100% pedal input / load but still.... logs have captured oil pressure continuing to dip in a turn while the user is in a region of the oil pressure map that should be achieving 60psi+ and they are at 20-30psi.

The issue isn't that "30psi is not enough oil pressure at 3,000rpm" because that SHOULD be plenty of oil pressure to be honest. The issue is that the oil pressure is supposed to be 60psi+ thus indicating that the 30psi the sensor is seeing is aerated oil thus indicating an oil pickup issue and thus resulting in significantly reduced load capacity of the oil film. 30psi of aerated oil is not the same as 30psi of air free oil.

Also, oil pressure sensors have a resolution and logging has a resolution as well. The accusump will dump oil in between shifts indicating pressure dipped below the 60psi of the electronic switch I chose... but logs show 80psi still. To catch the "trough" of oil pressure in a momentary bit of starvation is not guaranteed just because you are logging. I know after logging hundreds of autocross runs I had a few logs showing as little as 10psi at 3000rpm. Just a matter of the sensor/log grabbing a datapoint at the exact moment of the lowest low. Just another consideration... TLDR: the problem could be even worse than a basic log would indicate.

[rac]

Originally Posted by bbnks2

An accumulator is a very simple installation and relatively affordable. If you're doing this type of driving it's really a "might as well install one" type thing imo.

i agree, my comments are really targeted at those chasing the perfect oil pressure after they have implemented the simple stuff. i would go one step further and say a simple baffle in the sump is also a no brainer, without going crazy on complex trap door and plumbing solutions. its the 80/20 rule, none of the solutions for a wet sump is a 100% solution until you switch to a dry sump.... i've seen people chase this mirage for years without ever being happy.

Originally Posted by bbnks2

And I have logged and posted similar logs. Timestamp 1474 he is back on throttle with rpm and boost rising over 3,000rpm (engine is loaded) and oil pressure is continuing to drop. I know on a dyno my n55 PWG car made as much as 507wtq on the stock turbo at 27xxrpm. He's not at 100% pedal input / load but still.... logs have captured oil pressure continuing to dip in a turn while the user is in a region of the oil pressure map that should be achieving 60psi+ and they are at 20-30psi.

is this with or without the accumulator? if it is still happening with an accumulator and a basic sump baffle then i guess more time resources is warranted. i would add a pressure sensor to the accumulator and log it find out exactly how it is being depleted and go from there. ideally the accumulator should be controlled by a programmable valve to make best use of its volume.

Originally Posted by bbnks2

Also, oil pressure sensors have a resolution and logging has a resolution as well. The accusump will dump oil in between shifts indicating pressure dipped below the 60psi of the electronic switch I chose... but logs show 80psi still. To catch the "trough" of oil pressure in a momentary bit of starvation is not guaranteed just because you are logging. I know after logging hundreds of autocross runs I had a few logs showing as little as 10psi at 3000rpm. Just a matter of the sensor/log grabbing a datapoint at the exact moment of the lowest low. Just another consideration... TLDR: the problem could be even worse than a basic log would indicate.

i thought this might the case judging by some of the data i've seen posted. cant see it being a sensor issue, it must be logging frequency. i can log up to 1000hz, i guarantee i could pick up those dips if they were occurring at the place of the sensor. i havent tracked the car since having this set-up, maybe when i do the data will keep me awake at night.... lol.

[bbnks2]

Originally Posted by rac

i agree, my comments are really targeted at those chasing the perfect oil pressure after they have implemented the simple stuff. i would go one step further and say a simple baffle in the sump is also a no brainer, without going crazy on complex trap door and plumbing solutions. its the 80/20 rule, none of the solutions for a wet sump is a 100% solution until you switch to a dry sump.... i've seen people chase this mirage for years without ever being happy.



is this with or without the accumulator? if it is still happening with an accumulator and a basic sump baffle then i guess more time resources is warranted. i would add a pressure sensor to the accumulator and log it find out exactly how it is being depleted and go from there. ideally the accumulator should be controlled by a programmable valve to make best use of its volume.



i thought this might the case judging by some of the data i've seen posted. cant see it being a sensor issue, it must be logging frequency. i can log up to 1000hz, i guarantee i could pick up those dips if they were occurring at the place of the sensor. i havent tracked the car since having this set-up, maybe when i do the data will keep me awake at night.... lol.

MHD is 10hz I think? not sure tbh I know the canbus is the limiting facto because MHD is polling 30 pids or whatever.

Oil pressure dips were without the accumulator. With it I have not seen below 30-40psi. It smooths the dips pretty well.

[AndyW]

Originally Posted by bbnks2

MHD is 10hz I think? not sure tbh I know the canbus is the limiting facto because MHD is polling 30 pids or whatever.

Oil pressure dips were without the accumulator. With it I have not seen below 30-40psi. It smooths the dips pretty well.

My experience is similar. This is why I copied your setup.

[imported_mega]

Does anyone know of a replacement 30 PSI normally closed switch I need to bump up the pressure a tiny bit on my accusump setup and my switch is bad anyway. Solenoid is still good I would just power it up all the time but I don't think the moroso setup can take continuous duty

[Dieselboy]

AndyW bbnks2

Trying to decide between using a manual valve versus an EPC, and what the benefits are besides convenience. The EPC will allow discharge at a specific PSI (< 55PSI for discharge in the case of the 24-275X) while an open manual valve will constantly empty and refill based on the engine pressure to accusump pre-charge pressure ratio?

So, using an EPC, the accumulator will fill above 60PSI, and since it won't release until below 55PSI, it can fill a larger volume, and with a larger fill volume the initial discharge rate will be faster.

For example, with an EPC using a pre-charge of 10PSI and the engine hits 80PSI, the accumulator will fill and hold 2.63qt until discharge at 55PSI. Where as with an open manual valve, the useable volume in the accumulator with the same pre-charge is 2.45qt at 55PSI?

So the benefit to the EPC is more oil discharge at a faster rate when open?

[Dieselboy]

I've plotted it out here. I assume the EPC valve will immediately trend along the blue line once it's opened. Another thing to consider is that the EPC will not allow oil to refill the accumulator until 60PSI, where-as a manual valve will allow oil to trend along the blue line in discharge and recharge. I suppose the benefit of this is that engine oil pressure will be returned to 60PSI more quickly? Are there drawback to forcing excess oil into the engine and holding it there until 60PSI is reached?

[AndyW]

Originally Posted by Dieselboy

AndyW bbnks2

Trying to decide between using a manual valve versus an EPC, and what the benefits are besides convenience. The EPC will allow discharge at a specific PSI (< 55PSI for discharge in the case of the 24-275X) while an open manual valve will constantly empty and refill based on the engine pressure to accusump pre-charge pressure ratio?

So, using an EPC, the accumulator will fill above 60PSI, and since it won't release until below 55PSI, it can fill a larger volume, and with a larger fill volume the initial discharge rate will be faster.

For example, with an EPC using a pre-charge of 10PSI and the engine hits 80PSI, the accumulator will fill and hold 2.63qt until discharge at 55PSI. Where as with an open manual valve, the useable volume in the accumulator with the same pre-charge is 2.45qt at 55PSI?

So the benefit to the EPC is more oil discharge at a faster rate when open?

I think that is one benefit. It only helps for less than 5 sec no matter what, if I remember my calculations correctly from several years ago. I also think it is how you view the system... a continuous extra surge volume or an emergency injection. I've seen race cars(PRO 3) with the manual Accusump so it's certainly a valid choice. I have the view that I want the engine oiling system to operate normally...unless it needs a boost, so I like the EPC model.