Tom NJ
$100 Site Donor 2026
Originally Posted By: jstutz
Im not sure i understand the 16 to 29 mpg spread.
The 16 mpg was when I had a sensor problem, but I had three other readings between 16 and 17 mpg, probably from traffic jams. The 29 mpg was a 500 mile road trip after a tune-up, but again I had five other readings between 28 and 29 mpg. And that is my point - we do encounter traffic jams, take long trips, and have engine or sensor problems, and trying to see small oil effects is nearly impossible among the effects of all the other numerous and often larger variables. I discount the best 10 and worse 10 readings and just look at the range of 95% of the data points. This data falls between 19 and 26 mpg or 22.5 average +- 3.5 mpg or 15%. My current car is also showing a wide range, from 20.5 to 33.2 mpg. Eliminating the extremes still gives 22 to 30 mpg or 26 +- 4 mpg, still +- 15%.
I don't doubt that other cars and other driving patterns may give a tighter range, but seeing a 3% change from oil would take an awful lot of data to acheive statistical significance. When someone reports a 10% improvement from changing an oil brand, they are undoubtedly seeing noise from other varibles, not oil.
Tom NJ
Im not sure i understand the 16 to 29 mpg spread.
The 16 mpg was when I had a sensor problem, but I had three other readings between 16 and 17 mpg, probably from traffic jams. The 29 mpg was a 500 mile road trip after a tune-up, but again I had five other readings between 28 and 29 mpg. And that is my point - we do encounter traffic jams, take long trips, and have engine or sensor problems, and trying to see small oil effects is nearly impossible among the effects of all the other numerous and often larger variables. I discount the best 10 and worse 10 readings and just look at the range of 95% of the data points. This data falls between 19 and 26 mpg or 22.5 average +- 3.5 mpg or 15%. My current car is also showing a wide range, from 20.5 to 33.2 mpg. Eliminating the extremes still gives 22 to 30 mpg or 26 +- 4 mpg, still +- 15%.
I don't doubt that other cars and other driving patterns may give a tighter range, but seeing a 3% change from oil would take an awful lot of data to acheive statistical significance. When someone reports a 10% improvement from changing an oil brand, they are undoubtedly seeing noise from other varibles, not oil.
Tom NJ