Anyone running an Accusump in their setup? (Check valve/setup)

[cleantune]

I'm considering using one, but after talking to a rep from the manufacturer, I'm not sure. The check valve that is recommended to be installed before the "T" fitting right before the oil goes back into the engine, poses as a flow restriction in the system (obviously).

They had mentioned that some drivers were seeing a significant drop on oil pressure with the check valve, so they removed it. Supposedly, oil will still make into the engine without the check valve, but I'm wondering how much (roughly, like half?) and if it would be enough to still be effective in the case of oil starvation.

Anyone who has one of these installed, has experience with these, or just experience with hydraulic systems in general is more than welcome to weigh in on this.

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[djsilver]

The oil pump doesn't have a discharge check valve, but it would still tend to resist reverse flow back to the sump to some extent.

When I had one, I installed a bullet type check valve on the outlet of the accumulator with a small hole drilled in the plug to control the refill rate. That way if the accumulator had to discharge into the oil system, it wouldn't starve the engine while it refilled after the pump started feeding again. I didn't have a cooler so I had it connected to the oil filter housing with the pressure switch.

[Matt93SE]

What Don said.

Lots of racers have been running them for a long time and the lack of check valve is not an issue.

I also just happen to have a 2qt Accusump at the house I'm not using. I bought it used and never got around to installing it. includes tank, manual valve, and gauge.
I'll make you good deal on it.

[cleantune]

Thanks guys, thats good to read that you guys have both heard similar things about the check valve (drilling a hole in the middle is a good idea too). So if I do install this maybe ill install a pressure guage on the line before the engine block to have more of an idea of what the pressure is like. The Rep explained that it would be best to install one thing at a time, for example the oil cooler and filter relocation, then later add in the Accusump- for potential problem diagnosing urposes. He also said to run the precharge at 10psi (easier to read on gauge) and to put a shield around the safety valve on the Accusump.

They said they are switching to an "EPC" valve which will only empty the sump when the minimum pressure sensor switch is triggered. They said this EPC unit is more suitable for racing where the engine RPM ranges fluctuate, while the manual valve is more suitable for racing around a constant RPM range; reason being that with manual valve, sump is constantly emptying and trying to fill.

They also said either valve should only be about 1-2ft away from the tank and no 90 deg fittings. The other part of this that kind of scares me is how much air could get trapped in the system starting with about 5ft of empty -10AN hose; although they said that just running the motor and turning it off with the Accusump valve open would be enough to purge out air with one or two final high revs to fully fill the tank before it is closed.

Thank you for the Accusump offer Matt. I forgot to mention that I had picked up most of the parts for this about a year or two ago; just been looking for the time to plan out the install and find out more about it before installing it. I'll keep this in mind though if I hear of anyone looking for one.

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[Def]

Does an accusump really definitively help engines that tend to oil starve? Seems like you're constantly fighting around the fact that you're sucking up air in the oil pump in the first place. Plus the changing oil volume relative to pressure causes some additional problems.

Just curious if someone has data showing it works as well as the Mfg says...

[Matt93SE]

Thousands of racers have been using them for some time now. they seem to do the job on the occasional short-term oil-starve problems. I wouldn't think it would help if you're constantly running out of oil early in the turns, but for those places where the gauge just flickers, it will now stay much more solid..

[cleantune]

Does an accusump really definitively help engines that tend to oil starve? Seems like you're constantly fighting around the fact that you're sucking up air in the oil pump in the first place. Plus the changing oil volume relative to pressure causes some additional problems.

Just curious if someone has data showing it works as well as the Mfg says...

This is a very good point, and air in the system during just the initial startup was and still is a main concern of mine; as well as pressure fluctuations. I think what Matt was saying is also true- it is (or at least should be) better than not having any "backup" system to combat a drop in oil pressure. It may only be to recover from a slight drop in pressure only for a brief moment like Matt said. I'm wondering how many people use 2 oil pressure guages with these? or if it would be best to just have one right before the oil line goes into the engine?

I'm wondering if by not installing the checkvalve (to allow some backflow) at the "T" fitting would help purge the air out that was sucked in during a high lateral g moment (that would uncover the oil pickup); assuming a complete uncovering of the oil pickup. The engine should still get priority with the oil discharge; although I'm not sure if the backflow direction would be the path of least resistance (10-an to pump VS 10-an to engine)

The other factor is the valve that is used for the setup. With the precharge set to 7-10psi, the tank should stay full unless a severe oil press drop occurs; there should not ever be excess oil in the pan that the crank will be fighting through (one of the other concerns with a manual valve; although a moment like this would occur under the same circumstances with an electronic valve..right?)

I always question modifying an already functioning oil system, but there are so many people that have used these in pro competitive engines with success and if people use these on their planes, there must be a high level of trust with the product and functionality purpose.


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[djsilver]

I had mine setup with a 12v solenoid off the key switch. The first time I installed it, I overfilled the oil by a half-quart, started the engine, and let it slowly fill thru the pinhole in the check valve. I then shut the car down and the solenoid valve trapped the pressurized oil in the accumulator. I then checked and adjusted the oil level. Afterward, when I turned the key on it would pre-oil the engine with enough pressure to turn off the oil pressure light for a few seconds. I would turn the key on, wait for the light to go off and back on, then start the car. That way it provided both pre-oiling and emergency protection while running.

If you really want to get fancy, maybe you can adapt a swinging oil pickup from the Viper engines. http://i40.tinypic.com/2zjkwgn.jpg

[cleantune]

I was going to start a new thread, but this thread is on topic with something I found and wanted to share with all of you:

1. I heard the same advice from a Canton Rep- "check valve isn't needed and restricts oil flow".

- when flow decreases, pressure increases, so the same amount of oil will be moved, just at different flow rates, which may be ok for smaller engines that idle at low oil pressures?

2. the EPC valve

- opens the valve at a fixed psi pressure, determined by the psi rating of the pressure switch used.

The KA24de engine I have been using has a low idle oil pressure; even lower with 10-AN oil lines with a cooler plumbed in. The pressure switch would need to be lower than the oil pressure in order to work properly, but at this pressure I'm wondering if an override switch should be installed (in addition to the one that turns the system on) to bypass the pressure switch, allowing the accusump to "charge" to a higher psi?

The sump valve would still open at the lower set psi, but a higher pressure oil would be released for a faster response?

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Also wondering about the air in the lines as we were all talking about earlier. Fluctuations in the lines should be limited with the EPC valve, but would most/ all of the air be purged out by just running the engine and opening and closing the valve multiple times to empty and refill the accusump?

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