Aluminum Dry Sump Tank Questions Options

[gnomefabtech]

Hello All. I'm using one of Ben's aluminum dry sump tanks and am having some issues with the motor "wet-sumping" and flooding out my turbo.

I have a cracking valve in the oil return hose and I'm pretty sure the oil isn't coming in that way, but I'm wondering if it can come in through the scavenge side instead. I don't have a check valve in there because I assumed (yeah I know what happens when you assume) that the outlet was above the oil level and there would be no way for it to return that way.

Is all I need a check valve on the scavenge line? Does Porsche have one there on it's stock dry-sump setup? I'm not running a Porsche engine but it is a dry sump.

Thanks.

[gnomefabtech]

The important number is the height of the top of the oil in relationship to your cracking valve. I asked CHAT GPT to do the math and, for a stock height tank, it's between 1 and 2 psi to hold the pressure.

Learning this, I installed 2psi cracking valve on the hose going into the engine. This seems to hold the oil on that line. What I didn't think of was the other hose because I thought it dumped out in the air space like yours. I think on Ben's tanks the oil level might be above that, so there can be leak down. Plus the content of the filter dumps back in too. None of the filters for a 911/914-6 have a drain-back valve.

After some searching I found a modern oil filter with a silicon anti drain-back valve that should fit. It's off a 2009 Range Rover.

https://www.rockauto.com/en/moreinfo.php?pk...5340&jsn=23

I'll report back once I see what happens. My setup is a unique science project, but hopefully what I learn will help others.

[GregAmy]

The important number is the height of the top of the oil in relationship to your cracking valve. I asked CHAT GPT to do the math and, for a stock height tank, it's between 1 and 2 psi to hold the pressure.

Fair point, I'm using a Canton 8.5qt vertical tank. I'd say my total column height is around 1.5 feet max.

What was your height for those calcs?

Any idea what the suction psi is for a typical scavenge stage? I'm using a modified CB Performance 2-stage pump. Overcoming 2-3 psi should be pretty easy, yeah?

[gnomefabtech]

The important number is the height of the top of the oil in relationship to your cracking valve. I asked CHAT GPT to do the math and, for a stock height tank, it's between 1 and 2 psi to hold the pressure.

Fair point, I'm using a Canton 8.5qt vertical tank. I'd say my total column height is around 1.5 feet max.

What was your height for those calcs?

Any idea what the suction psi is for a typical scavenge stage? I'm using a modified CB Performance 2-stage pump. Overcoming 2-3 psi should be pretty easy, yeah?

At that height CHAT came up with around a 1psi cracking pressure needed. I doubt that any pump would be affected as long as the valve cross section is large enough.