last week i did alot of 55mph backroad driving (about 7 stopsigns on a 18mile drive to work).... and i filled up and i was at 16.2mpg

this week i have been working about 45miles (oneway) from home and i drove the freeway all the way all week at about 80-81mph and i filled up today and it came out to 18.3 mpg

its a 00 5.4 f150 SC with an airaid intake and dual exhaust...... this is my best mileage yet...... but normally i do alot of mixed driving and come out around 15.....

 

Wonder what this weeks mileage would have been at 65 MPH !

 

i physically didnt believe it... i checked it like 3 times, and i know the odometer is right...as far as speed 65-70 is prolly the best number for mileage, seems like when i go 55 my mileage was "ok" but it took forever to get there.... so my thinking is lets say i went 80mph for 80miles which would be one hour (1700rpm) (without stopping) if u were driving 55 the tach is at about 1400rpm and it takes 1.45 hours to get there.... if u multiply 1400 times 1.45 it comes to 2050... which means for how much gas i burnt up driving for an hour vs going slow for about an hour and a half i couldve driven 90+ at 2000rpms and still been ahead... im basing all of my figures on the fact that at each rpm increase the amount of fuel increased is the same. im not sure if my figures are anywhere right..... but i bet im on to something.... all i gotta do is figure out the rpm that works out perfectly for my truck and i could get better mileage yet.'