barshnik said:
A few weeks ago I poured 1/3 of a shot glass of bio from the 2 gallon can that I get filled from a friend of mine that home brews bio into a 16 oz. clear plastic soda bottle (cleaned & dried), filled with diesel at a recent fill up, and gave it ONE quick shake. That translates to the 2% that I've run since new, always pouring 1 quart into the tank before a full fuel fill (proprtionally less for less than a full tank fill). That bottle is as totally mixed without any seperation as the day I filled it, and I'd notice as the bio is a bit darker than the pure diesel. I'll trust my own eyes, and for the tiny bit (2%) of bio that I run, I think splash-mixing is fine.
It's the "one quick shake" that does it, barshnik. The thing is that your fuel tank doesn't get "one quick shake" unless you roll the car upside down at least once. You might get a good mix putting the bio into a nearly empty tank, and then filling with petro d2. Indeed, if you are only blending to B2 in the first place, you are right, you are probably fine. And at that low concentration, complete solubility is probably assured.
It is when you blend to higher proportions of biodiesel that "splash blending" is more likely to get you into trouble with stratification.
I am a chemist, and I've made blends of commercial soy biodiesel from 10% to 90% LOOKING for stratification (as well as for gel protection). And I can tell you for a fact that I see it, especially in blends around 50/50. In fact, at 50/50, it is difficult to avoid it without several minutes of vigorous agitation.
Our aussie friend who insists the normal jiggling of a car in travel combined with the trickle of fuel being recycled to the tank will prevent stratification is simply wrong. I've done the tests. He would know better if he had done them, too.
If you want to see really pronounced stratification, put two small bottles of petro and bio into your refrigerator. Equal volumes of each. Let 'em chill below 40 degrees F, and pour them together. Shake the h**ll out of the mix and put it back into the 'fridge so it doesn't warm up. Note the cloudy appearance of the mix. This is one sign that it is NOT a homogeneous mixture.
You will find the next day that there is no doubt there is stratification. It is well known in the fuel industry that while EVENTUALLY biodiesel and petrodiesel will completely dissolve in each other, REAL mixing is needed to avoid stratification. While they do dissolve in each other IT ISN'T INSTANT.