The tailgate up or down question is as old as mileage improvement theories are.
Also one of the simplest to figure out yourself without any science or math.
My 52 chevy 1/2 tonner gains about 2 miles or 10% with the tailgate level with the ground and a full tank on the freeway around 70mph.
It's the cheapest, simplest and most reliable way to increase your mileage for freeway drives.
I do this drive every month and whenever I have to drive with the tailgate up, it's always about 10% less mileage.
If you research the tailgate question on the internet, it shows that most modern trucks are designed to get best mileage with the tailgate up.
Acetone does not increase milage on a stovebolt.
I tried several mix ratios and the effect on mileage was zero.
The motor did sound and feel somewhat different and you could smell the acetone at the exhaust - nothing more.
I am anything but a conspiracy theorist - I am just always very delighted if anything gets done right at all.
If acetone or ANYTHING else would give you cheap and easy increase in milage, EVERYONE would know about it...
