Went down a rabbit hole a little bit on turbo oil flow.
Installation Data holset hx40
1. Mount the turbocharger on the turbine inlet flange. All other connections must be flexible and heavy pipework
should be supported. Always pre-lube with clean engine oil.
2. Always position the bearing housing so that the oil drain is at the bottom and kept within 22° of the vertical centre
line when installed on the engine.
3. Oil should be filtered below 15/20 microns. The oil quality must be as specified by the engine manufacturer.
e.g. API - CD (MIL - L - 2104C). Improvement in life can be obtained by using super high performance diesel
(SPHD) oils, particularly where extended oil drain periods are used.
4. Oil pressure must show at the turbocharger oil inlet within 3 - 4 seconds of engine firing to prevent damage to
turbocharger bearing system from lack of lubrication.
5. The minimum oil pressure, when the engine is on load must be 210 kPa [2.0 kgf/cm2, 30 lbf/in2] and pressures up
to 415 kPa [4.0 kgf/cm2, 60 lb/in2] are satisfactory. Under idling conditions the pressure should not fall below 70 kPa
[0.7 kgf/cm2. 10lbf/in2].
6. The oil inlet pipe should be 9.5 mm [0.375 in.] bore minimum and the oil drain pipe should be 19 mm [0.75 in.] bore
minimum. The oil must drain downwards by gravity from the turbocharger into the engine under all operating
conditions.
Normal oil temperature is 95+/-5°C (203+/-9°F). It should not exceed 120°C (248°F) under any operating condition.
11. Oil return pipes are permitted to decline at an overall angle of not less than 30 degrees below horizontal.
15. Recommended oil flows for the turbochargers are 2 litre/min at idle and 3 litre/min above maximum torque speed.
Tldr, 2 Lpm at idle.
Found a couple other sites where 2 Lpm at idle is mentioned, and one where the test is to put oil feed line into a jug and idle engine for 15 seconds.
I'll do that before I bolt on the turbo...once turbo is on it'd be better to pull the drain off but that could get messy.
I guess if I get a s***load more than 2 Lpm out of it, I'll restrict it, but I'm thinking it'll be no restriction, and don't skimp on the drain.
Kinda curious now.