I run most all of my engines at 50-1. Make that all of them...

The Chinese engines take a long time to break in and it's quite common for the planes using them to exhibit black exhaust tracking behind the stacks for quite some time. I don't run super short stacks so i do not get any of that residue inside the colw. I do get it splattered on one h-stab, under one wing, and back a ways on the fuselage. The quantity depends on how many flights I do before cleaning any of it off. Usually a lot of flights before I get around to doing anything about it so it can be a bit messy.

The DA's, 3w's, BME's and other American/European engines get the break in job done sooner but I would not expect to see any of them done in less than 10 gallons of gas.