a little more info from deadbolt:
We recommend at LEAST a 12X12X12 box for shipping most turbos, for large turbos, a 14X14X14 box is recommended. DO NOT USE IHI TURBO BOXES!!! THEY ARE TOO SMALL AND ALMOST ALWAYS ARRIVE DAMAGED!
We have outlined safe packing tips to help you avoid extra cost and annoyance at having your turbo get damaged in shipping. PLEASE FOLLOW THEM, we have been doing this for quite a long time and know what works and what does not.
Wrap the turbo HEAVILY in bubble wrap, make sure that the turbo is sealed from any packing materials getting inside. It is VERY time consuming to dig packing peanuts out of the housings and we will have to charge our standard labor rate for that time.
Place the turbo in the box with the bottom oil return return line facing UPWARDS or to the SIDE. The BEST way to ship them is with the heavy, cast iron portion down towards the bottom of the box, and the compressor side facing up. We have seen countless damaged turbos because the lines or compressor housing were left facing the bottom. In shipping it will work its way through the shipping material and wind up contacting hard surfaces such as truck floors, shipping docks, etc. This damage is very expensive, and if it occurs your core refund will be reduced.
Pack the box tightly with heavy duty packing material, leave as little room for the turbo to move as possible, if the turbo moves inside the box, the risk of damage increases dramatically!