well, the least mpg i had was about 250, but that was always boosting and most of the time with the A/C on. but with normal driving, some highway most city driving and boosting most of the time,
i usually get at least 280-300mpg <---- mistake/typo

edited:
280-300 miles per full tank, hehehe

 

There is a big thread on this topic under General, BTW...

AWDrifter21, not to be a pain, but I'm pretty sure you meant miles per tank If you are getting 300 MPG there is a bunch of scientists in white lab coats who'd like to talk to you!

Using the yellow light as an indicator (and using miles-per-tank at all) is a really innacurate way to measure your fuel usage; in my 02 WRX, the yellow light comes on when anywhere from 13.5 to 15 gallons have been used, leaving 3-6 gallons in the tank. I've driven 40 miles with the yellow light on and still had at least two gallons in there (and for the record, don't drive it dry because you'll be sucking gasoline sediment into your fuel line).

In my own experience with several cars besides the WRX, there are a lot of factors that affect fuel use BESIDES your driving style. They are:

1) Sticky performance tires definitely degrade gas mileage. The wider and stickier your tires are, the more force it takes to peel them off the ground, especially from a full stop. 225 tires with a soft compound will kill 1-2 MPG right there. That's why taxi drivers use super-hard belted radials at 40 PSI.

2) Ambient temperature is a big factor. My old Isuzu Trooper II got 19-24 miles per gallon (measured correctly, not estimated by tankful) in Ohio, and 16-20 MPG in Arizona just 6 months later. Hotter engines burn more gas, and even if you don't move, your temps change enough during the seasons to make a 2 mpg difference.

3) A/C use is a BIG factor. Right here in AZ I lose 4 to 6 MPG comparing January (median temp 78 degrees, no A/C) to July (median temp 106, A/C all day and night). The A/C just kills gas mileage if you use it every time you drive, and there is nothing you can do about it.

4) Fuel additives. Ethanol and MTBE gas additives add oxygen to your fuel, and oxygen doesn't burn (contrary to popular belief). Oxygen *assists* burning, but the more oxygen and additives in your gas, the less "room" there is per gallon for the actual combustible fuels. So, 10% additives mean that you are getting 10% less fuel per gallon, and thus will have to burn more to generate the same amount of power. Insert paranoid rant about fuel additives being a government/oil-company conspiracy right here.

In addition to all of those factors, THEN you can consider loose piston rings, clogged injectors, bad tuning problems and all the other problems an engine can have.

 

I always get about 25 to the gallon highway, but that's probably cuzz i drive like a granny.....i would have to agree with the others that it has a LOT to do with driving style...

 

so if i change my gas (76) i would also get better mpg?

 

You could. My friends and I have notice on average a increase. Its not a lot, maybe 20 more miles to a tank.

 

What gas would you recommend? I commute to Fremont on a daily bases and I would like to save as much money as possible.

 

I really like valero. It's usually cheaper than anything else and its really good gas! Most people don't remember this but Valero gas was formerly known as Exxon. I would use 76 or Valero. Chevron is supposed to be good gas, but I don't trust that techron shi*t. Also, Chevron is the same price as 76, and 76 is a lot better. But for everyday driving I would go with Valero. Go to the Valero on Stevenson and Fremont Blvd, they usually have the cheapest gas.