So a few weeks ago, I installed a turbo back exhaust and I found that I had a leak on my UP to headers. My setup was a Cobb UP, Helix DP and Skunk2 CBE. So an obvious indication of my leak was that I was doing horrible MPG, I think when I got to the last tick on my fuel gauge I did ~240 miles. So I replaced it with a 07 STi UP and supposedly the leak was "fixed". I thought I was doing my regular MPG because when I got to half a tank, I was at ~150 miles. But after that, my fuel just started going down quickly. So at the third tick I was at ~250-260 miles. I just wanted to check with others if I am doing average MPG. I calculated that a stock 03 WRX does ~300 miles. I haven't finished the whole tank yet, but am I back to normal MPG? Or rather, do you think I am still leaking?

FYI: I still have the check engine light, which I was told activates fail safe mode and sort of kills my MPG as well.

 

If you get full boost and don't hear screaming sound during cold start you are most likely not leaking. As for for decrease in gas mpg, you are most likely doing more of spirited drive - since it's more fun to drive with those mods.

 

also, if you think you were in safe mode or something, you should reset your ecu by disconnecting your battery and pump your brake a few times.

 

hey man, if u wanted, last night i could have ran a data log on ur car to see if something was wrong..

and btw, i do 90 miles a day in wrx and i get about 160 at the 1/2 tank mark, and i get to about 280 when im at 1/8th tank(right between 1/4 and empty btw lol) and im a protune so i get purdy good gas mileage...

i am almost poistive due to ur mods u are running very rich and this is y u are not getting the mpg u want.. even tho u do drive very conservatively.. its just running too rich, even stock wrx's can't pull 300 mpt if u drive spiritedly...

 

Yea I'm pretty much stock besides suspension and my gas mileage on my '03 is about 160 halfway through and then 250-280 depending on how I was driving (spirited or granny). Your gas mileage seems normal, and I dont think you should worry too much about a few miles if you're runnin the car hard (like it should be ran) anyways =p. Built to drive.

 

hmmmmm am running Turbo Back exhaust set up also ... never even went close to 300 miles to the tank even when i was on stock setup. The most i ever got was around 285 with COBB AP Economy Mode Map. My Check engine light is on due to no signal from O 2 sensor and i think it is decreasing my mileage

 

CEL = destroys gas mileage

 

i installed the up pipe for him, so i know there wasn't a leak when i was done..

but if he would have showed up at the meet last night i could have data logged his car and seen what was wrong...

but i think he's just getting normal gas mileage with no tune on up pipe, dp, and cbe completely catless and a CEL, so i think his mpgs are bad due to for not having some sort of EM...

 

its your right foot causing the bad gas mileage.

 

he claims he shifts at 2750ish rpms... so im guessing he never goes over 70 mph on the freeway cause on the 5 spd thats very close to 3000 at 75-80 mph...

 

if you can get 300 miles a tank it sounds about right to me. the fuel guage is not that accurate...it's just an estimate for you to tell u when to fill up.


i get abour 300 miles a tank mixed freeway/city.

however if i did all freeway, i can get just over 27 miles per gallon.

 

ya.. same here.. i just am getting close to empty and my tank says i have gone 296 miles...

 

fill your tank, drive a few days, fill tank again.

miles driven / gallons to re-fill tank = mpg.

that's really the only way to tell.

 

so i gotta get my CEL fixed ASAP

 

ya, just buy that mechanical cel fix that i posted on your thread... 25$