[Mifunego]

Greetings from Chicago, IL! I’m a current owner of a 2008 Mazdaspeed3 (2.3L turbo, 6 speed manual, hatchback) which is my daily driver and a 2006 VW Jetta (2.0L turbo, 6 speed DSG, sedan) which is our family car. I’m somewhat of an automotive enthusiast and have modified pretty much all of the 15 or so cars I’ve owned. Generally I’ve modded for more performance, i.e. acceleration/speed, but if you think about it, faster in many cases means allowing the engine to perform more efficiently. Of course, what you do with that efficiency is another matter, but I digress. Anyway, I’ve kept a log of fill ups in a variety of cars since 1998 which are all on my mileage log that I save to Google Documents if anyone is interested. I have been slowly adding to my log online here, but I have only added a few lines of data so far.

I have made attempts to improve the mpg in the Mazda by the more common methods (slow down, shift sooner, pump up the tires, free-flow air filter) but either I’m not doing it right, or my right foot is still too heavy because I haven’t seen much if any improvement in the daily commute mpg. I’m averaging marginally better than EPA estimate, but nothing to really brag about. The best mileage I ever got in this car was fully loaded with a family of 4, a kayak on the roof, and all the goods we needed for a long weekend at the lakehouse. I assume that was due to the consistent (cruise control) relatively slow speed that was all on the expressway. My daily commute from Chicago, past O’hare to Lombard, IL doesn’t fare nearly as well, although that is almost all expressway as well.

The Jetta does about 20% better mpg overall despite its nearly 100% city use and "automatic" transmission. Although I have read that the electronically controlled sequential clutch transmissions are more efficient than a typical slushbox, I’m still surprised that the VW does as well as it does. We’re averaging around 26mpg in the city. The only mod to this car has been the APR reflash of the stock ECU. I knew that this reflash did a heck of a lot as far as increasing the power, I wouldn’t have guessed that it would help with the mpg too.

I’m considering lighter wheels for the Mazda next Spring, when the winter wheels/tires come off. The stock 18” are pretty darn heavy and the stock summer-only tires are notoriously fast wearing anyway. I would likely go with a slightly taller tire to effectively change the gear ratio, allowing the engine to run a bit slower at highway speeds. Presumably this would have a beneficial effect on mpg. Of course I’d need to follow the GPS for a more accurate odometer reading, but as past experience tells me, it is worth it at the gas pump.

So anyway, glad to be here, and keep up the good work, all. I enjoy reading the tips, tricks, experiments and especially the success stories!