A "slow car fast" post the other day got me thinking about the potential of each car, fast or slow.

*Not my car. But close.

While "fast car slow" isn't really a thing, you CAN play the Jeremy Clarkson M3/Prius game (and yes, since I mentioned Clarkson and the Prius in the same sentence, you should have pronounced it in your head like him - Pry-us).

By that, I mean what kind of fuel economy can you REALLY get if you try? My E36 M3/4/5 is rated 18/26/21 (city/hwy/combined), and I'm usually right around 20-21 in mixed driving - so I'm actually decently close. I have a near 20 mile commute (each way), about 70% city, and I usually wring it out once each way.

Yeah, it's somewhat masochistic, but the week I got my best I realized a couple things.

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First, I was always working for a clear lane, and pulling away from the pack. Stoplights were worse - when I was in front, I almost universally had a couple car lengths on the next car by the time I got to the speed limit. I didn't really speed, but 2-5 over was routine, maybe a bit more if I was working for lane choice or a turn lane.

However, when I REALLY try, I've gotten a personal best of 24.8 mpg. Revs stay under 1500 until it's in 5th, lots of coasting, timing stoplights, etc. Speed limit, maybe 5 under. Way further under if I see a red light ahead while I coast down. I don't miss as many green lights as I thought I would, though you do have to occasionally drop the hammer to scoot through instead of catching a red and waiting a cycle (responsibly - I always keep it less than 5 over on residential streets).

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The biggest revelation was how much my ego was tied up in it all. Watching a Prius pull away from me was downright insulting the first time. But even when I thought I was going as slow as I could REASONABLY go, I was still accelerating faster than about a third of the other cars next to me. And when I was doing this, I stopped cussing the people going so slow and started respecting them.

And that's what brings me back to potential. It may be easier to use more of a slow car's potential in everyday driving, but I also think it's harder to use LESS of a fast car's potential. It's not just the mechanics of it, but there's also the psychological bit that makes it that much harder.

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So here's the challenge: what kind of mileage can you get? To make it fair and inclusive, we'll go from your car's EPA numbers. Teal Geo Metro or Ferrari 599, how much better can you get than you car's rated mileage?

So go home tonight and fill it up at your normal place. No topping - topping is bad anyway, and if you go back to the same pump when you're empty it should be close enough.

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Figure out your best route, and do the city/highway math. Mine will be about 29% city/71% highway, so I need to beat 20.3 mpg average.

Who's in?