i tow about 5k lbs. and drive the same route every week all year long. i always hand calculate my mpg at every fill up because im **** like that. i was getting between 12.5-13.0 mpg with the worst ever being 12.2 mpg only once or twice. i installed an afe progaurd 7 drop in and have gone through a couple tanks so far, and my mpg has dropped to 11.6-12.0 mpg. the truck has been the same in my sig except for the xzt which i just added today when i got home from work after filling up the last time. has anyone else had this happen? the stock filter had 8500 miles on it and the filterminder was getting sucked down 1/3 everytime i drove the truck. now it doesnt move at all so im sure the filter flows way better but im wondering if now the ecm is adding extra fuel to match the extra airflow causing less mpg??

 

Have you noticed any change in your boost pressure? That is where the computer will react and add fuel.

 

i will have to re-install the factory filter to see if theres any difference in boost. i think i am going to do this tomorrow anyway because i want to see what kind of mpg change the xzt will give me and i cant base it off of the afe after only running it for a few tanks.

 

on a side note, if anyone is curious why my mpg is so low to begin with, its because i tow in the city all week from house to house all day long. i will leave in the morning and drive for about 1/2 hour and then the truck will sit for 1/2 hr.to 1 hr. then i will drive for 5-10 min. to the next job and the truck will sit for another 1/2 hr to 1 hr. and so on all day long every day of the week. im sure this is probably the worst driving conditions not only for mpg but also for engine life. on the good side i do get close to 19 mpg running empty on hwy trips though.

 

alright, i removed the afe drop in and surprise surprise my sensor, intake tract, and turbo all had a light coating of oil on them, not much but definately oily to the touch and wiped off onto paper towels. btw, i did not add any oil to the filter during installation. i dont even have the oil kit, this was a brand new afe drop in filter and i actually thought it looked a little dry in some areas of the filter because i could still see some of the white media so i doubt it was overoiled from the factory. anyway i cleaned everything up and re-installed my stock air filter, disconnected my xzt (so that the only difference between the last couple weeks and today is the filter) and went for a drive. i imediately noticed two things. first of all the turbo definately spools up a little slower, it is very obvious on the boost gauge. next thing i noticed was that i actually make 1psi more boost now w/ the stock filter, i have no idea how or why..... all i know is that i will NEVER use another oiled filter again. also i noticed that the filter didnt seem to seal up that great either because you could actually see where the dust was getting past some areas of the seal, and the dust had stuck to the oil in the piping and on the turbo. this makes my weary of even trying an aftermarket dry filter, but if i do try one it will probably be the amsoil nanofiber. i will leave the xzt disconnected this week and fill my tank back up monday morning and after the week is over i should be able to see if i gained my mpg back or not, we will see. i still have the question, why did i lose mpg w/ a better flowing filter? was the ecm adding fuel or was it because my sensor was coated w/ oil? anyone got any ideas?

 

Since this tank is blown already, I would put the XZT on so you can play with it and get that out of your system. Get used to the feel of it and how it performs before you try to do a mileage test.

 

i guess i could play w/ it a little this weekend. any thoughts on how i picked up 1psi peak boost w/ the stock filter??

forgot to mention, i also noticed my egt's are higher w/ the stock filter also, about 50 deg.