Hi guys!
So I'm upgrading to a Garrett T3/T04E 50 trim turbo and just want to start some discussion about oil drain lines.
After talking to people, doing hours of research and looking at hundreds of pictures I have a few concerns. So usually when people upgrade to these larger turbos they use the stock drain line and simply cut out the center section of the tube and then clamp on some high temp silicone hose. Now there have a been a lot of concerns over this, mostly about longevity of the line, the drain angle and also the inner diameter of the tube. Personally, I don't really want to do this and would much rather prefer mocking up a more durable and better drain line.
So my first idea was, well Ill just tap the the stock oil drain hole and go to some -12AN line, that will provide a crap ton of flow, there will be no leaks or durability issues and it will look freaking awesome (even though no one will ever see it 
).
After doing lots and lots of research on pictures and talking to people, mostly the following:
60 Trim turbonetics Turbo
Garrett 57 trim turbo
TD05 16G I believe
GTX30
PTE5031E
So as you can see almost all of the drain angles are not vertical and mostly horizontal with some small dips. I am extremely concerned with this because I DO NOT want oil backing up into the turbo, causing it to smoke, or even worse, the link kinking up, blocking the drain and boom there goes my $1000 turbo.
So at first I said well why not just tap the stock return and put in a -12an line. This would solve the issue of durability and no leaks and it will be a bigger drain! But then it hit me I'm just going to have the same drain angle issues as using a cut stock line.
So my next Idea was to tap the oil pan and IMO this seems like the best idea when using a larger frame turbo. The oil pan can be a bit difficult to get off but with Boxpin's instructions (by jacking up the motor) it shouldn't take too long.
So im at the point now where i would like to discuss the best place on the oil pan to put a bung.
You have two options:
- Weld on a bung (ensure zero leaks ever)
- Drill and tap a hole (The aluminum pan is thin so it will be difficult to get enough threads in it and also there arent too many awesome spots)
So here is what I have in mind
All the way to the left, I circled two flat regions that would be good for drilling and tapping. As you can see the far left of the two is up higher so there wouldnt be any issue with oil from the pan working its way up there. The second region is still flat but there is a little less room and it is not as high. For both of those spots, in the actual pan there doesnt seem to be anything in the way. IMO you would need to use a AN 45 deg fitting in order to avoid hitting the block, which might happen with a 90 fitting, Ill have to do some measuring.
OK moving on.The next two options and the squares on the oil pan ribs. Now my concern with these is that they are on these little ribs, which will make drilling and tapping near impossible. my idea for these was to use a weldable bung which will fill up all the gabs, etc that drilling into the rib would cause. Once again there would be no issues inside the pan. You should be able to use a 90 degree fitting.
Using the pan will give an almost vertical drain path which is optimum. Also both the opinions will allow you to either run the line in front of the drive shaft, or behind depending on your turbo setup. IMO in front of the drive shaft would be optimum because that would give you a much steeper drain all the way down.
So I decided I would post up all my research and basically as much information as I can.
I am looking for suggestions and ideas, so anything and all is welcome 
~Matt