Go back an page and see that I tried Liqui-Moly's MOS2 additive in my 2006 Civic at the end of July. The plan was to run this for many months and compare to prior tankfuls ... as well as tankfuls run around the same time last year.
However, I just sold the car on Friday, the 4th.
So, I only have very limited data to go by. Still What I experienced showed significant improvement in fuel economy. And if you reduce drag enough to see fuel economy gains, you will likely see similar power gains as well. That's called a win-win ... and it cost me $7.
Comparing 3 tankfuls with MOS2 to the 3 prior tankfuls, I saw an improvement of 13.1% fuel economy. Now, the time I was using MOS2 was warmer, on average, but that's still quite an increase. The car hasn't seen consecutive tankfuls with these kinds of numbers in a few years.
The test period also included a test drive by the car's new owner ... who did not use my daily hypermiling habits. A significant handicap.
Comparing the MOS2 tankfuls to the same 2 month period last year, the increase drops to 4.4%.
During this time with the MOS2, I was using MOS2 in Valvoline Max-Life ... a non starburst oil which will not give you that last tenth or hundredth of a percent fuel economy increase. Another slight handicap.
Bottom line is, I'm sold. This stuff works ... I just can't quantify it as well as I'd hoped.
I'll be adding this to my S2000 next oil change as well as my 2015 Mazda3 as soon as I feel it's broken in ... about a year or more from now.