Unbelieveable fuel economy
 

Hi All: This is my first post. I just bought a used, great condition, 2007 Mazda5 (old car was a '96 Buick Park Avenue) with the manual transmission. This weekend (Family Day long weekend!) went from Toronto to Ottawa and back... 980km including noodling around in Ottawa, but nearly all highway miles. I really tried for maximum fuel economy, I drafted trucks the whole way, and only trucks that were doing the speed limit (100km/hr), and stayed on the 400 series highways the whole way there and back. I avoided flooring the accelerator at all. Yes, it was a very boring journey, but I couldn't believe the poor fuel economy figures I have read about concerning the Mazda5 - I mean, a couple of Miles per gallon better than a Caravan? Puleeze, I was sure I could do way better in a manual 4-banger that weighs way less. So I went 950 km round trip and consumed 60liters of gas. That's 6.3 litres/100km, or 45 Miles/gallon!!!! I can't believe it, seeing as how the "average" reported mileage for this car has been (to me) so piss poor for the engine size. People must be really gunning it hard. Has anyone else been able to get good mileage out of their Mazda5? PS: I wouldn't recommend that anyone draft trucks like I have done. It takes a lot of concentration and is a dangerous, and for most people, foolish, thing to do.

Tailgating large trucks will dramatically improve your mileage, however, if done properly you are almost tailgating and can't see in front of the vehicle you are following. This is very dangerous. It was a good experiment but please don't do it again. This is deadly.

I just calculated the mileage @ 37.2 MPG.
950 km X .6214 = 590.3 miles.
According to Liters to US Gallons (Liquid) converter , 60 litres = 15.85 US Gallons.
Maybe you used Canadian gallons, but on websites such as this we need to use US.
590.3/15.85 = 37.2 MPG US.
According to Mazda USA, http://www.mazdausa.com/MusaWeb/disp...ehicleCode=MZ5 (click on Engine & Mechanical) a 2012 Mazda 5 is supposed to be 28 MPG highway, so you did well.

Good catch, UseYourNoggin, on the conversion error... I believe your right. Still pretty impressive nonetheless. There are some common-sense things you can do to eliminate the risks involved but I wont elaborate - I do not want to encourage people. I am just very pleased to have both an incredibly versatile car and also one that is capable of very decent fuel economy.

Something from the web on drafting - you don't have to tailgate to get good results. * In scaled wind-tunnel tests, driving 100 feet behind a semi at 55 mph will reduce drag on your car by 40%. The drag reduction increases as you approach the bumper of the truck until you get a 93% drag reduction at a distance of 2 feet. * In road tests, the testers achieved an almost 20% improvement in gas mileage at a distance of 100 feet (at 55 mph) and a 45% improvement at 10 feet.

So, 37.2 mpg then; pretty good for a Mazda5. That said, there have been a few folks with Mazda5s with manual transmissions who have reported mid thirties for fuel economy; it seems most of the horrible mileage reports come from automatic transmission equipped Mazda5s (which is contrary to the "Official" EPA numbers).

FWIW, I once went from a small town outside of Port Huron Michigan across Ontario and into upstate New York and on into Albany on one tank of gas in our old 3.8 liter 1998 Dodge Grand Caravan; a distance of 504 miles for a calculated 28.2 miles per gallon. I would have gotten even better had it not been for long queues at both border crossings and both bridge tolls, and of course the one hour and sixteen kilometer crawl through road construction in Hamilton. Ontario is a good place for getting good mileage. :)

Those are nice stats. How close did you draft? :eek: :confused:

I didn't draft very close. If you've ever done it you feel a zone of turbulence behind a truck from 100 feet out to, maybe, 50 feet. In this area the wind resistance is reduced a fair amount. Then even closer than 50 feet, the wind noise vanishes and your almost in a vacuum, literally getting pulled along. If you are nuts, and draft withing 25 feet you would get 60+mpg. I tried to stay in the turbulent zone where you get decent mileage.

I would have gotten a bit higher, but on the way to Ottawa, on Saturday, I ran into a snowstorm, and traffic crawled for about 50km - a bit of stop-and-go thrown in.

I do a fair bit of cycling with friends, so I know the benefits of drafting. On a bicycle over 30kph the air feels as thick as water. I once drafted a TTC bus and could maintain 55kph behind it (I was in better shape then).

The trick with trucks is to pick one that slows down a lot on hills. You'd think you'd want to follow a truck that maintains a steady speed, but the one's that have to slow on the hills are heavily loaded. A heavily loaded truck cannot stop very fast, so is safer to follow. An empty truck with eighteen wheels can probably stop faster than your car and is very dangerous to draft behind.

One time I had to drive 60 miles to pick up a large hydraulic cylinder in an older pick up truck that we used to plough snow with. I had to drive with plough on it so I did the same thing as you did. I was afraid of it overheating with the plough on it, that's why I drafted.