What would be the best placement for a drain

 

Above the level of the oil in the pan.

 

Don't run a drain below the top of the oil line in the pan otherwise it wont, you know, drain....

 

Most factory vehicles drain below the oil level of the pan, I’ve got 5-6 cars returning this way, works fine. Make sure you have proper crankcase ventilation.

 

I've never seen one do that in 30 years of owning turbocharged vehicles.

 

Many do, and companies like Greddy and others sell turbo kits with Banjo bolts that screw into the factory drain bolt hole into your oil pan for a turbo drain. I’ve certainly never had an issue, and the people who have likely had other underlying problems such as poor ventilation.

 

Never seen any company like Greddy offer that.

No idea what that vehicle is you're posting a picture of, or if it's even a turbo drain ? Perhaps if turbo is very high up, and there's already substantial gravity drop into the large diameter hose.....a drain then below the level of oil may be ok.

But it is not the correct or recommended way to do things.

 

Oem quality is good enough for me, not to mention the fact I’ve done it on at least 6 cars.

Simple google search will show you the greddy parts I speak of, along with many replies if people regurgitating that it won’t work, while the people actually using it saying it works great.

 

Nissan, VW, Audi, etc all hve factory systems this way, again, it works fine.

 

So you're saying that the oil level drops faster than the oil is being returned to the pan from the turbo preventing it from backing up into the turbo?

 

If that is what happens, then yes it should work in the rare installs who do it that way. It would need a very good gravity drain though...ie a high mounted turbo.

because on the flip side.....with enough g-forces in the right direction, you will have oil trying to get rammed back up that pipe effectively blocking the drain. Which you would never want to happen.

If a few OEM's do it like that though, you can be sure it will have been thoroughly tried and tested before actually sending the cars for sale

 

I'm pretty sure the reason this works is after the engine is running there is a couple quarts of oil missing from the pan . It's in all the oil flow passages , the turbo feed line, the turbo , in the rocker valleys, etc. When the engine is running , the pan is no where close to dead engine pan levels. Forcedfed did a test, if I remember right, where he had his drain just above the low oil sensor hole and started pouring oil in the engine , running, with the drain hole open and returning oil from the turbo somewhere else (for the test). He had to overfill the engine with 2 1/2 quarts before the oil started coming out of his regular drain hole. So I guess the dynamic oil level is much lower on our turbo engines with the extra spaces we have for the oil to travel through. Makes sense if you really think about it. I still like my return above the LOS hole.

 

I saw a decent enology once. Glass of water with a straw in it, the water in the straw is always a little higher in the straw, than the glass, right? Pour water in the straw what happens? Does it fill up, or does it displace what you’ve added as you add it and maintain that level? It maintains.



Agreed, buddy of mine brought me a Huron speed kit to install on his car. When we got done the turbo was so damn low it was uphill to the top of the pan! I drilled and tapped about 3” above the drain plug and she’s been mint ever sense, the drain line is basically flat, I’d say 3/4-1” drop over a 20” span. I don’t like it, but it has worked without any hint of oil smoke. I thought for sure we were going to have to buy a scavenger pump. On all my setups I run a minimum of 10an from each valve over to a catch can, new setup I went to twin catch cams for each side with 12an on this s488

 

Contrary to popular belief.. You can tap into the pan lower than the oil level. Have a well flowing large drain may be slightly a bit more critical, but you can do it.

 

When the engine is running, and the oil system is pressurized, the pump is constantly pulling oil from the pan at the same rate it is pushing it out the high pressure side of the pump. So for this reason of course you can put the drain below the oil level line because it is getting pulled back in actively by the sump. Above the oil line it is a passive drain. There are obviously limits to any design but fundamentally speaking it works fine.

 

Have done it many times with zero issues. I always make sure the turbo is forward of the drain.
It's a myth that it will prevent the turbo from draining properly. It will drain until it reaches the rest of the oil, whether that is in the pan or the bottom of the drain tube.
Its also a myth that it will cause the drain oil to aerate, when draining below the oil level actually helps prevents air from getting into the drain hose.
That's not really an issue since the oil level in the pan drops considerably during high RPM, and it is likely to just be draining above the oil level again.

 

Yup, same reason a fuel pump return is plumbed below the fluid level... and that is a pressurized return.