I get 13-17 mpg and live in SF.... I've got a DP and tuning.
Get rid of your BOV! and...
Welcome to SF driving... kiss your mpg good-bye!!

 

i get about 18 city, 26 hwy, which isn't bad at all for a bone stock, brand new WRX wagon. anyone else notice that the price of gas dropped like $0.15 in the last week? it was around $2.92 here in the berkeley area for premium, now its back down to $2.77 as of yesterday

 

Getting a new ECU such as an ECUTek will not only help power (IIRC people are getting approx 10 WHP on a stock WRX) but it will also help gas mileage. Since it will be changing your AFR to a still safe but leaner condition you will be putting in less fuel and making more power.

With my a VF35 I get around 21 MPG.

 

You can check your front O2 sensor as it's used for closed loop feedback, although your mileage is not that bad.

Mike <--- 12mpg City, 15/16mpg Hwy

 

That doesn't sound too far off, actually.

I get 24mpg overall.

I filled up a few weeks ago when gas was $2.99, and the fillup cost me $42.00. I get 310 miles (roughly) out of a tank. Half of that is $21.00 and 155 miles.

It would help I guess if you were more accurate with your measurements. Fill up COMPLETELY, instead of chucking $20-25 into the tank. Drive a few hundred miles. Fillup again. Net out the gallons and divide into the miles traveled.

 

10mpg on 100 octane.

 

 

Fully catless with Cobb Accessport w/ 91 Stage 2 map I would get about 23mpg with 80% highway. I would get 21-22 with stock downpipe.

Want better gas mileage? Get a Honda Civic, or a Hybrid (but of course the Hybrid will
cost more to buy).

 

When I had my wrx, I got about that in town too, unless I was riding it like a banshee. I had Cobb AP on St II, MRT 3" TBE, Helix Flex Uppipe, and various unrelated to gas mileage mods. I sped everywhere and it was rare for me to not see at least 250 on a tank.
That was at altitude, even.
Maybe you all don't know how to drive? :P
After I sold the car, the mpg went down to 18... turned out the fuel pump had a loose hose. Problem solved.

 

Altitude helps, actually. Less O2 molecules per piston stroke = less fuel added to keep the same A/F ratio.

When I drive back and forth from here to Washington, I spend like 500 miles at 5000 feet of elevation in the middle of Oregon. I would go from, on the same trip, averaging 22 mpg on the highway to averaging around 27 while at that altitude. BIG difference!!!

...and those are 100% highway tanks so there is very little variability besides the altitude change...

 

Shhhhhhhhhhhh...

"Oxygen tends to settle to low places, due to atomic weight molecular theories and gravity. Oxygen levels found at 5,000 ft. are a full 14% less than levels found at sea-level. At 10,000 ft. this percentage loss of oxygen now approaches 30%. As carburetor jets remain fixed, the diminished oxygen in the thin mountain air will burn poorly with the carb's fixed amounts of fuel. The logical outcome is black smoke from the tailpipe, and poor mileage, and significantly reduced power outputs."

I had to get on my gas harder to get the same effects you get down here.

 

Lol. Your car isn't carbureted. It doesn't apply. A fuel injected car automatically adjusts fueling to compensate, whereas a carburetor is tuned and set and must be re-adjusted for changes like that. If it's set to give enough fuel at sea level and you drive up into the mountains where there is less O2 molecules per volume air, you will still be getting the same amount of fuel but will have less O2 and will run rich... which is why that quote mentions smoke from the tailpipe.

Again, it doesn't apply to a fuel injected car. On top of that, a turbo car will run higher pressure ratios in order to compensate for the thinner air. The thinner air is also easier for the turbo to compress. On a percentage basis, a WRX will lose much less power going to a higher altitude than an N/A car. You should't have to get on it much harder to get the same effect.... although there is still some power loss.

Not sure where that quote came from, but Oxygen does not "settle" in low places. Air closer to sea level is more compressed because there is more air on top of it pushing it downwards. The air as a whole is denser. There are more O2 molecules per cubic [volume of whatever kind], and there are more molecules of everything else that make up air also. The partial pressure (which is the % of each gas making up the air) DOES NOT change with altitude. If oxygen is 21% of the air content at sea level (which it is), that % stays constant no matter the altitude....

Hope that makes sense... sorry for being so nerdy, lol

Jeremy

 

wow thanks for the feedback guys. So I guess i'l just have to deal with it