Quote:
Originally Posted by suspectnumber961
Well...I'd rather test stuff when the weather is getting warmer and they switch to summer gas (end of April?).  |
In my crude way I was trying to point out that if one wants to show any oil additive (or any other technique or technology) in the worst way, simply schedule the test to coincide with the cold or cooling weather(*). To show them in the best light, test in warmer than a standard day or warming weather.
The reason why I spend so much time in testing methodology is to eliminate these climate effects. I really want to know what is reality, not which way the weather blows.
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Quote:
Originally Posted by suspectnumber961
Interesting graph you have...but what is the part about draining a qt of oil...did you test overfilling by one qt? Or under filling?
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When we change oil, some of it remains inside the oil pan and other galleries. But once the new oil is put in, this undrained oil mixes with the new and changes the characteristics from virgin to a mix of virgin and used oil.
What I've done is take three samples with these known quantities:
#1 - old oil, drained 2 quarts
#2 - virgin oil
#3 - added oil, 2.5 quarts, before treatment
I'll get back three oil analysis with about two dozen metrics. Then using partial fractions, I can calculate what percentage was left in the engine:
X#3 = (n-1)*X#1 + (n)*X#2
I don't know how much old oil remains in the engine after it is drained but by having three samples, I can calculate the percentage of old to new oil. The only fly in the ointment is the potential of a gunk layer in the bottom of the oil pan. I have certainly seen that in my transaxle oil testing.
I am seriously thinking about dropping and cleaning the engine pan on the next, 1,000 mile change. But I'll have to get a sealant and scrape off the old sealant and that takes time. Still, doing it once every +100,000 miles, sounds like a small enough price to pay.
Bob Wilson
* - Auto magazines did this by trying to run the Prius and other cars in the dead of winter. The "Green Human" faux test tried it too with an 8,000 mile, highway driving test from Maine to Washington State drive only to find at best, a tie. The mileage reported, 40 MPG, indicates they weren't really respecting the speed limit.