what about adding 2 cycle motor oil? what kind and how much?
yeah, that's what we're saying. 2 cycle oil, spec TC-W3 (it will be listed on the back of the container)... The ratio is like 128:1, which is basically 1qt per 30 gallons fuel. Any more than that, and you decrease the fuel's cetane rating.
Improves lubricity of the ULSD fuel now mandated for 2008 highway diesel engines. I wouldn't run this concoction in an '08, as it will add to the particulate emissions of the engine.
However, your 7.3L was designed to run on 1500ppm sulfur, which provided more lubricating properties in the fuel itself.
I started running it, then added a cetane booster, and my fuel economy improved quite a bit.
I've since gone to B20 bio (bio diesel has greater lubricating property than pure petroleum ULSD) with a cetane booster, and my mileage has continued to improve. I was getting in the high 12's when this little experiment started, now the truck is getting in the low 15's pretty consistently.