Basic Fluid Dynamic Question (Oil Return on Turbocharged Car)

AI Thread Summary
The discussion centers on the oil return setup for a turbocharged 1979 Volvo 240, where a 1/2" NPT bung was welded into the oil pan instead of tapping the block. The oil drain from the turbo has a consistent diameter of approximately 5/8", but the engine's 15° cant creates a slight upward section in the return line. There is a debate on whether this upward section will cause significant drainage issues; one viewpoint suggests it will only back up to the outlet level, while others worry about potential problems. The turbo oil drain operates under flow rather than pressure, and while crankcase pressure may slightly increase with boost, it is believed that drainage will not be severely affected. Overall, the setup is considered workable despite the upward angle, with an estimated oil flow of about a pint per minute through the turbo.
propav8r
Messages
6
Reaction score
0
Ok-I'm actually looking to settle an argument on another forum. I have turbocharged my 1979 Volvo 240, and converted to a later style motor. Instead of drilling and tapping the boss in the block for my oil return to the oil pan, I welded a 1/2" NPT bung into my oil pan. The approximate inner diameter of that bunt is 5/8".

The oil drain outlet from the turbocharger is also approximately 5/8" inner diameter, giving more or less the same hose diameter all the way back to the oil pan from the turbo drain.

Here's the argument though. The engine is canted approximately 15° over to the exhaust side, meaning that the oil return has a slight upward section before it dumps into the oil pan.

My line of thinking is that the oil level in the drain hose will back up some, but only to the level of the line outlet. Others seem to think that it will cause major drain issues, which I just don't see.

I should probably mention that turbo oil drains don't see only pressure, only flow. The turbo itself is fed from a -4AN line with pressure varying from 4 bar to 1.5 bar, but once the oil has gone through the turbo, it loses it's pressure.

Can anyone more well versed in fluid flow than myself help me answer the question? I've included a pictoral for further explanation.

IMG_3677.jpg
 
Physics news on Phys.org
Heh-206 views and no answers...
 
ben-stein_1.jpg
 
So what would a garden hose do in the same situation? Allow flow and when the flow was removed the only fluid left would be even lower than your blue marker. When your engine is making boost, the crankcase will get more blow by and increasing the crankcase pressure a little bit. This might cause the drain level to rise up a bit (no more than 1/2 an inch) but the fluid will still flow.

It is not ideal but with your turbo mounted higher, you won't have a drainage issue. FYI about a pint of oil will flow through your turbo per minute. I have added turbos to three separate vehicles.
 
That was my line of thinking.

As for pressure in the crankcase, there shouldn't ever be too much-my PCV isn't recirculated. I'm just using a road draft tube instead. Not too friendly for the baby seals, but we've got too many of those already. :smile:
 
Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'
So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not. So far so good. What puzzles me is this , there is a term average magnetic flux or "azimuthal mean" , this term describes the average magnetic field through the area swept by the rotating Faraday...
It may be shown from the equations of electromagnetism, by James Clerk Maxwell in the 1860’s, that the speed of light in the vacuum of free space is related to electric permittivity (ϵ) and magnetic permeability (μ) by the equation: c=1/√( μ ϵ ) . This value is a constant for the vacuum of free space and is independent of the motion of the observer. It was this fact, in part, that led Albert Einstein to Special Relativity.
Back
Top