With that variation seen in only two tanks, how could you ever possibly ascertain a small change due to the additive?
This is even worse than that article that I linked a while back where even at the same station (and same grade) the energy density of gasoline varied 4%. The article concluded that it is impossible to determine real-world fuel economy without extraordinary measures including using test fuel designed to be uniform. Besides fuel the effects of wind, weather, and driving style/habits were just too large to give meaningful results.
This is precisely why anyone who tries to show that a small change in fuel economy is due to a specific variable is just fooling themselves.
Originally Posted By: John_Conrad
update on this is as follows:
I drove almost 800 miles on the 5w20 HM pennz(794.2 actual) and ran 2 tanks of fuel. No additional addy's in fuel or oil.
1st tank returned a 24.276 miles per gallons, which is unusually low for my vehcile, but this fuel was not my normal E0 i use, this was my last tank from a trip into Nebraska on thanksgiving and was 87 octane E0. On this tank, I also did the 20 minute run of B12 for a flush, so those 2 variables may explain my low mileage.
my second tank of fuel was my normal fuel at my weekly same station fuel up with 91 octane E0. This tank returned a 32.4 mpg. This mpg is much more what I expect from my weekly drive of 90% highway and 10% city driving.
I do all my fuel ups until the tank will take no more, so I can eliminate that variable from the equation.
taking the 24.276 and 32.4 mpg and averaging them I have a 28.338 mpg average on the oil alone.
I added the MOS yesterday afternoon, the MOS is a very nice almost clear but with a hint of tan color to it. I was impressed with how it looked and flowed.
I will observe it over a couple of tanks and report back.
and on edit:
the minor oil leak did not appear to have been helped by the HM oil alone at least on the first 800 miles, as i jacked up the vehicle and checked yesterday morning,so i went ahead with the MOS.
I have new card boards to put under the vehicle this evening so i can track this also.