Oil feed and drain.
 

Hello guy,

I have a BW 6758 I will be using there are what appears to be oil channels behind the head of my 01-05. I also have a boundary oil pump with a plug that I can remove. Could I use the oil pressure from the head and could I drain my oil to the oil pump. Please refer the picture.

thank you.
https://cimg6.ibsrv.net/gimg/www.mia...a4d7e5b5c.jpeg
https://cimg7.ibsrv.net/gimg/www.mia...73c36f8a8.jpeg

I would probably not try to use that drain spot in the oil pump as the return. It looks a big smaller then you generally want to run. I also am not sure how straight of a shot the actual line would be from the bottom of the turbo, especially depending on what manifold you are using.

As for the oil feed off the head, I believe that has been done before, but I think in generally we just all feed off the oil tee port due to it being the known.

Oil feed and drain
 

Thanks for sharing your thoughts, I wanted to explore all my options before I committed to a solution.

The concern with feeding from the head is that there is a restrictor in the oil galley between the block and the head. This limits how much oil flow the head gets, and if you pull a bunch of that oil off to feed a turbo then there may not be enough left for the cams. When Mazda needed more oil in the head to run the VVT on an NB2, they ran an extra oil feed line separate from the cams.

I don't know of anyone who's actually blown up a motor this way, but it's not the obvious win that it appears to be.

--Ian

Oil feed and drain.
 

Thanks for the info I've decided not to go this route after reading both of your recommendations. Old fashion way is tried and true.

EFRs are sensitive to supply pressure and drain sizes. With my initial setup (Boundary VVT set to 72psi, 4AN from the oil pressure switch port to turbo, -10 drain hose) was pushing a significant amount of oil through the internal seals.

First, I investigated the drain size. I found that the -10 fittings have ID's smaller than the 3/8NPT port size on the bottom on the CHRA. The EFR manual states to not decrease the ID below that port size (0.57") for gravity drains. The -10 fittings I used got as small as 0.46" in some places. I increased the size to -12 and there was less oil pushing through the seals, but not there was still some.

Second, I added an additional oil pressure reducer (Turbosmart makes on that is returnless for simplified plumbing). After installing the OPR, all the oil was staying inside the CHRA.

I see you have already made a choice. But to add to the Boundary pump decision, that plug you point to on the pump is where the dip stick goes into the sump on front wheel drive versions of the pump and B6 engine, so it is a relatively straight path, but it enters above the oil level. So it works for a pressurized oil feed return, but not for a vent to atmosphere catch can return.

The bore is the size of the dipstick tube od, which may or may not be big enough for a return oil feed.

I once tried to connect the oil pressure gauge off the side of the head using the plugs you show, as it is more accessible (for a FWD version). But I read 20 psi there, when the oil pump was delivering 40 psi at the bottom end, and only 5 to 10 psi at idle. The restrictor feeding the head makes a difference in pressure as well as flow.

After doing some fact finding the oil feed requires 1 bar of oil pressure not to exceed 4 bars to operate the EFR 6758 safe and without smoking. I will pressure test the oil feed line from the head and measure the output and if it falls with in the 1-4 bar range I will route the oil feed line from the head, at that point I would feel comfortable that I am not starving the head or turbo. I will post data once I do this for future refence for others interest in this method.