ORIGINAL: hobbsy
Sean, that raises an interesting question, I run Fox 5% nitro/20% either all castor or 50/50 castor/syn blend, if the 1.60 spits less oil, where does it go? My theory is that certain mufflers, Bissons for example, do a better job of blowing the oil away from the plane because of the crimped outlets which would accelerate the exhaust gasses. I dunno, but it's a thought.
I think your muffler theory may well be correct. After all the oil has to be going some where.
While I certainly don't own enough 4-stroke engines to draw any sweeping conclusions, from running Saito, OS, and Magnum 4-strokes on the bench where the oil is more or less trapped after leaving the engine I can't tell any difference in the amount of oil "spit".
jess