Chicago Mazdaspeed3 checking in...
 

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!

Welcome, welcome.

Your fuel log entries show a nice jump at the end of Oct to the beginning of Nov. Is that the comparison you're making? (Trying to get a sense of what you consider a "decent" improvement.)

If that's the case, you may already know that this is the time of year northerners' fuel economy would normally tank anyway due to cold weather. For the average driver, cold has a significant impact.

So your improvement may be real, but masked by the temperature hit. You could check against last year's fill-ups at the same time of year (if it's the same kind of driving you're doing).

If the car doesn't have a fuel consumption display, I'd also highly recommend getting instrumentation in there - either a ScanGauge or a MPGuino. Can't underestimate the importance of feedback for adjusting driving habits.

cheers-
Darin

Thanks. Actually what you are looking at on this site are just the few entries I've had the time to enter. If you'd like to see the entire spreadsheet I've kept for the car's fill ups, just click here for a more detailed explanation. A ecomodding guru like yourself should be able to make some more educated conclusions with a bit more of the data.

Of course, I didn't buy the car strictly for high mpg, obviously. I've done a fair amount of autocross and track days in my single life, and as I progressed into family life, I tried to find a car that would balance my kid-transporting and grocery-getting responsibilities along with my inner speed demon. There were few cars available (especially at the price I got this one) that covered as many of the bases as the speed3. I was very close to buying the Mini Clubman S, but I would have sacrificed space, about 90 hp, and maybe another $8K, but then my gas mileage would have been considerably better. Maybe next car. I don't expect to break any hypermiler records with the Mazda, but I'm sure I can improve on what I've been getting.

And yes, the car has an average and instant mileage display. Inconsistent and inaccurate. I only calculate mpg by filliing up the tank and dividing the number of gallons into the miles traveled since last fill up. Still, I guess it provides some value by showing a relative change in mpg instantaneously.

When did you start making a concerted effort to boost MPG?

Any car with a fuel economy display is potentially a hypermiling video game!

Relative comparison is key, yes. If the average display is resettable, that's the one I'd probably use in combination with the instant gauge. If you have a regular route/commute, I'd be playing for high score.

What works for me is keeping top speeds to 55-60 mph cruising, shifting at 2000 rpm in all gears except top gear, moderate acceleration (taping that imaginary egg to your gas pedal or shoe), and anticipating stoplights/stop signs and traffic slow-ups so you don't use your brakes.

I honestly don't remember - I didn't record it. I started in the early part of the summer, but eventually just fizzled out.


2000 rpm eh? Wow, that is low. I believe this 2.3L engine has the torque to do it without the fuel-hungry (but joyful) turbo boost, but I'm not sure how well-received I'll be in Chicago traffic. I just filled up yesterday, so I'll go on that acceleration diet starting today and see how it goes.

It works for me. Most 2 liter class cars get their best brake specific fuel consumption with moderate acceleration between 1500-2200 rpm. I'm getting about 170% of EPA combined mileage estimates with my two cars over the last 23,500 miles.

Welcome to the Ecomodder forums.

Agreed. The best investment I ever made was a ScanGuage. :thumbup: