Wow, Benjamin. Thanks for that turbo manual! Now that's bedtime reading. I also now know why people around here get so excited about VNTs.
Johann
To back up the above post, this is from a Garrett tech support manager talking about a VNT 25.
This turbo needs .3 gpm of oil @ 30 psi. minimum at full power. Any oil that you can use in the engine will work for the turbo. The oil drain uses one bolt and seals with an O ring. A flat flange with a gasket will also work. A .5 inch minimum inside diameter oil drain is recommended and must be within 30 degrees of vertical with no "sink traps" that will allow oil to puddle.
Taken from
here.