My 5 month project

[Howie]

Install the flapper valve under the oil filter stud.  Use a properly sized socket that has had the leading edge radius ground off as that stud is VERY thin.

I'd go engine, turbo, cooler & then back if it were me

[Dirty Duc]

Install the flapper valve under the oil filter stud.  Use a properly sized socket that has had the leading edge radius ground off as that stud is VERY thin.

I'd go engine, turbo, cooler & then back if it were me

I second Stew's routing.

[Speeddog]

Don't all of the turbo units get their pressurized oil from a gallery, and that oil is gravity drained back to the sump?

In that case the turbo oil is just bled off, so not much difference between the before/after the cooler issue.

Definitely needs an oil cooler, and keep in mind what Duck-Stew said about maybe two coolers.

[Dirty Duc]

Don't all of the turbo units get their pressurized oil from a gallery, and that oil is gravity drained back to the sump?

In that case the turbo oil is just bled off, so not much difference between the before/after the cooler issue.

Definitely needs an oil cooler, and keep in mind what Duck-Stew said about maybe two coolers.

Only on the ones that are mounted higher than the oil level in the sump.  A turbo mounted under the swingarm (unless it is a sealed unit like the Airesearch Bill Johnson used) needs a scavenge pump to keep up the oil flow.  Otherwise you can kill the turbo with coked oil in the bearing/bushing.