Oh ok.. thats good then. Yea if you don't have it already, an intake and exhaust will be good.. also some tuning. I just have a N/A lancer and when I added my intake and exhaust my gas mileage was the same if not better than stock. When I added the test pipe cat delete.. my gas mileage got worse.. then when I added the header on top of that it got back to around stock gas mileage. I get around 30 city and 38 highway with my Injen Intake, RRM test pipe, RRM Header, magnaflow catback.

 

Any mod that "frees up" lost horsepower by making the engine more efficient will increase power and also mileage (as long as you dont decide to take advantage of the extra HP with your lead foot). Some examples are lightened underdrive pulleys, turboback exhaust, IC piping, etc. Also just a leaner retune will use less gas. But dont expect to be getting 35mpg by strapping on a huge turbo and running a crapload of boost. More boost = more air = more fuel --> lower mpg

 

Dynoflash significantly leans out the Air/Fuel ratio and will improve both performance and fuel economy. Before tune I was only getting about 220 miles to a tank...but after tune it increased to about 280. After a year's saving in gas, it almost pays for the flash.

 

Fuel Efficient Mods = oxymoron. hahaha....

 

the flash does not affect closed loop driving. I don't see how a flash can increase mpg if you're just cruising. So basically you're only seeing an increase of mpg because you're keeping out of the gas more often then before you had the flash.