No, what this thread is missing is whether you have A/C on or not -- that's critical information. I get 300 miles per tank with A/C off, and 270-275 (as low as 250) miles per tank with it on -- I use the same type of gas every time (Shell Vpower 91) and drive the exact same distance every day (21 mile commute) at similar times, and that difference always shows up between summer (A/C on all the time) and winter (AC off).

 

I don't think I have ever used a full tank of gas with a/c on the whole time. I don't use the a/c very often, but obviously I use it more in the summer. If the a/c had a large impact in my mileage I would see a drop during the summer months. I will have to wait and see...this will be my first summer with this car.

I think the amount throttle used and driving conditions would impact mileage far more than a/c. When I drove up to lake tahoe I got 26 mpg with no traffic and hardly ever boosting. Then when I went to a car control clinic and a few "spirited" drives my mileage plunged to 18 mpg. Whats the main difference between these two types of drives...in a word...BOOST!!!

 

Year/Model 1998 Impreza Outback Sport (145K mi.)
Modified? Intake, header, cat-back
Octane used regular chevron (89???)
Milage 20-21 mpg
Mostly City or highway driving? mostly freeway 75+

... I know I get better mileage when I go closer to the speed limit (65) on the freeway- but does anyone know what the most efficient speed is? And would certain mods increase this speed (or overall mileage)?

 

What's your average speed on the freeway? I want to see those numbers if at all possible.

One more question... Would finishing off my exhaust by replacing the cat-section with something high-flow be good or bad for mileage?

 

Right at 65. I'm cheating though; I'm going up and down the mountains here, and I coast whenever I can keep it above 65 off the throttle. Probably 25-30 miles a day at idle, heh. So I don't think you can expect more than 28-29 mpg normally.

Probably good... but not enough to make up for the money you spent on it.

 

As I said, I have controlled for factors such as different driving styles, etc. and without changing my driving habits or styles AT ALL, the a/c makes a 30+ miles-per-tank difference, 100% of the time.

However, (and yes, I realize how useless one data point is), I took a trip a few months back which included about 220 miles of driving on soft dirt and sand, and I spent almost the entire time under boost -- essentially making a desert back-road into a rally course, with my brother as the co-driver. I drove the CRAP out of the car; near the end of the run I stopped and looked under the car and saw that the turbo was glowing red.

I got 320 miles out of that tankful. Go figure

 

03 WRX Wagon AT!!

STI intercooler, K&N drop-in, Perrin downpipe ,inlet hose, boost controller, MadDad connecting pipe (all 3") STI axleback.
About 13-14mpg City, 21 Highway. Aaaaaaa!!!!!!!!!
Not a nice driver though. Lead foot. Tried to take it easy, doesn't help much, deffinetly not worth it.....

 

Year/Model: '95 Impreza L wagon
Gas: 87, try to stay away from cheap no-name stations
Mods: nothing that would affect economy seriously
Miles/tank: ~24 city/a little more highway
Type of driving: Mostly fast city (~45-50mph)

I've managed to get 24 mpg by being as light on the throttle as I possible could. Cruising at constant speed (75-80mph) on the highway yields 26, maybe 27. Over the winter, if it's cold, the fuel economy goes down noticeably. Also, I've been keeping the tire pressure in my Sumitomo HTR+ tires higher than before in an effort to improve economy. I run 38psi front and 36 rear (+/- a couple psi)

 

2004 WRX STi
pde dp, tanabe cb, perrin crank pulley, blitz short ram
92 octane
19.4 mpg(personal best)
50/50 city/hwy
2.65 per gallon

2003 WRX(wifey)
stock
22 mpg
50/50
2.65/ gal

between me and the wife she definitely has the most mileage(50k on hers) i have 25k on mine. i posted my personal best- in reality i have an average of 17 mpg.
with normal to high rpm shifts as well.

aloha from the summit of *-^-Mauna Kea-^-*

 

2004 WRX Wagon
No mods
92-94 Octane (Premium)
Manual Transmission
Averaging 25 MPG
Almost all highway mileage (approx 30 miles each way to work)
Car has 34000 miles (ie, broken in nicely)

Over the years, I've likely had an average of 24mpg. I usually fill it up with about 13 gallons and having traveled between 280-350 miles

 

Got 26 mpg 2 tanks in a row so far. 2004 WRX w/ AC on. I'm in Hawaii so there is always traffic driving .

 

1998 Subaru Legacy 2.5 gt sedan
27 MPG (best ive ever got)
2.25 a gallon, some small place in my town sells for about 1.95 a gallon so i go there as much as possible
Regular Fuel
mostly driving around town

 

04 STi

got it brand new with less than 10 miles on the ODO and kept track of mileage.

never got the 24 mpg on the highway.

even when i took a trip a month after getting it (and broken in CORRECTLY) with a 1400 mil round trip where 95% of the miles was spent on I-5 (from san fran area to portland).

really disappointed by the number SOA gave...

now, and i still maintain records for EVERY fill up, i get 18-19 normal dailiy driving. 22-23 highway...



oh well... but when i press the GO pedal, all thoughts of mpg disappears... lol.....

 

What speeds were you driving on I-5?