I'm getting ready to install twin T04E's on my 5.0 HO with Edelbrock Pro Flo 4 EFI. The crate motor I'm using already has a bulkhead fitting in the side of the pan; however, the fitting is about half way up the sump - so it might be BELOW the oil level (see photo) To be honest, I'm not sure exactly where the oil level is on this pan. Will the gravity feed oil be able drain into the pan sufficiently considering where this bulkhead fitting is located? Since this is a mid-engine setup with the engine exposed, I have no packaging restrictions - the turbo's will be about 6" above the engine.

If the answer is no, I'd like to understand the physics since I don't understand the reason why it wouldn't drain if the tubo's are elevated above the engine. Maybe crankcase pressure plays into it <shrug>. Plan B - I presume I could dump the drain line into the valve covers - right? It's a MAJOR PITA to drop the pan - so I'm investigating all options.

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It needs to be above the oil level. The valve covers are fine as long as the drains run downhill the whole way.

 

The bulkhead fitting you are talking about is for the low oil sensor. If the turbos are gonna be that high above the engine draining it into the valve covers would be perfectly fine . You want as straight shot down as possible it should be at least a -10 size hose for the drain. Cool cab over by the way!

 

I don't think this is true, as long as the turbo itself is above the oil level the drain shouldn't care if its draining into empty space or into the pool. Manometery implies the drain tube is going to have whatever level of oil the pan has in it, flowing or not. I've been wrong before though.

 

I thought it was more about the froth that the oil was in exiting the turbo, and the speed that it could equilize in the pan. Its one of those things u hear and never really questioned.

 

If the crankcase had zero or vacuum on it, I think that might be true. But with the likelihood of having pressure in the crankcase, you will not want the turbo drain to back up against a reservoir of fluid.

In real life practice, this doesn't work. It will back up oil into your turbo. you will push oil out of seals. It won't work. It's one of those things that everybody just kinda "knows" without think as to why, but there's a reason. It won't work.

 

Don't skimp on the drains. Do whatever you can to make sure there is a clear path to the pan with no obstruction.
I'm fighting this now after filling my exhaust system up with 8qts of motor oil.. I've tried 2 different scavenge pumps and still pumped oil into the intake/exhaust system. So far it has done this 5 different times until I decided that the s-pumps can't keep up with the drainage.

Now I have removed the s-pumps and I'm welding in -16 drain lines for each turbo. I sure hope this works..

ks

 

I learned , above oil level, isolated from windage.
Ive always lined the drain up with a main cap and kept it high on the pan. Hasnt failed me yet.

 

Very good
Re-iterate: higher than the oil level on the running engine, free from windage, shielded if possible from windage (custom plated), angle slightly around 45* to straight down 0* (not sideways into the pan like a horizontal fitting at 90*)

also
You see alot of -10AN oil drains but the majority of turbo manufacturers recommend a -12AN as the minimum size