Fuel Economy Test #3: can opened windows kill fuel economy?

[evilsandwich2]

holy fuck 55mpg, if i get 14 mpg im excited

[landongendur]

@evilsandwich2 - That's one thing I do miss about the Metro

[cristian821987]

you can not mesure fuel economy on this level in the real world because there are 2 many variables like wind speed,bumps,overtaking.....

[punkmonkey123]

Are you a member of ecomodder?

[landongendur]

@punkmonkey123 - I was (screen name Peakster), until I learned how to live without a car entirely :)

[punkmonkey123]

@landongendur Well, I, being a lazy american, must live with a car, but 55mpg in my ford festiva makes it a little bit better. :D

[landongendur]

@punkmonkey123 - nice! ;)

[starlandliu]

So if there are no cars on the highway, should I fold in the side mirrors to boost fuel economy?

[landongendur]

Yup, folding the mirrors will do the trick. I actually did another test video where I got rid of my exterior mirrors entirely (and just had one big interior mirror) and it saved more than 2% in fuel economy.

[Zolar1]

Are you SURE about your numbers?

You said 80KPH, but when you calculated fuel economy, you said MPG.

80KPH is somewhere around 40MPH (roughly), and 100KPH is about 55MPH.

Try your test in the summertime, but then add the use of A/C to see any difference.

Also, did you remove the PS mirror? That too can skew the results.

[landongendur]

I removed the mirror to increase fuel economy. 80-km/h works out to be around 50-mph, so that's why the fuel economy is so great. The faster I go, the more air the car has to push. At 70-mph, the Geo only gets a meager 37-mpg.

[Zolar1]

Sorry, my math is off a bit. I stand corrected.

You mentioned KPH for your speed. How did you arrive at the MPG number?

[landongendur]

Km/h is what my original car's speedometer reads. The ScanGauge electronic device on the dash was calibrated to measure gallons consumed/hour and miles travelled per hour.

I like using the miles/gallon equation because it's the standard that Americans (and a sizable amount of the Canadian population) use when measuring fuel consumption.

[burns1210]

I'm going to be running a simular test with all 4 windows open, and the rear hatch open vs. closed on my Vibe. I assume the hatch being opened will help air flow but the hatch sticks up above the roofline increasing drag.

[landongendur]

Let me know when you complete the test. I'd be interested in seeing the video :) I also did the hatchback test in my test #2 "the importance or aerodynamics".

[hsttom]

ill buy that car from you!!!

gimme a price!

i get 14.1mpg in my car :'(

[landongendur]

It was totaled in a collision last March. Insurance paid me $1,690 for it. Now I'm riding a bicycle because gas in Canada here is now heading towards $6.00 a gallon. Every mile I travel on bike is like paying myself 25 cents in fuel alone.

[hsttom]

do you add acetone to your bike??

[landongendur]

Nope. I'm just saying that my old car today would cost 25 cents in fuel for ever mile I drive. So now that I'm riding my bike, I'm saving that amount every mile I travel with it (for example: I've now gone 263 miles on my bike within 1 month. So I could pay myself $66 since that's the amount of fuel I saved).

[hsttom]

ohh good point u rid ur bike in winter???

[landongendur]

Yeah, I sure do. I actually bought my first bike (used of course for $40) at the end of January and started riding it immediately after. When dressed appropriately cold temperatures aren't that bad. The only thing I'd change for next year is that I'll invest in a snow-mobile helmet with a visor to keep my face warm.

[Luvanicebum]

Well, usually when I have the window open, my elbow is resting on the door, so I imagine my exposed elbow is dragging me down and costing me money. Stupid elbow...

[landongendur]

At only 1.8% reduction in fuel economy @ 50-mph, I bet it's much better having windows down compared to A/C on ;) It would only be like paying 6 cents a gallon more for fuel (if fuel is $3.50 a gallon).

[Luvanicebum]

yeah, I never use A/C anyways. I need fresh air even if it's 90F out.

[infobelow]

Maybe driving the vehicle at 100 km/h or whatever the maximum speed limit on the motorway is in you country. You would find you get difference results. No one really drives around at 80 km/h on the motorway, too slow. Sorry if my English is bad.

[landongendur]

Your English is great.

Yeah, 80-km/h only works if you live in a place like Winnipeg Canada. The highest speed limit currently in this country is 110-km/h, so testing at that speed would make more of an impact I'm sure.

[playerjake12]

remember that your car went lighter because you used up some gas. Therefore, a lighter car will increase your MPG.

[landongendur]

I only drove about 40 kilometres during the experiment which is only like 2 litres of fuel. The weight difference is pretty small.

[itsbuta]

No such thing as a economy car no matter how car technology has progress .for the simple reason cars spend most of their time stuck in town and city traffic plus slow moving traffic on the roads. Therefore all cars are doing fuck all MPG. Excluding electric the only vehicles on the road that have good fuel economy are motorbikes because they don't be stuck in slow moving traffic wasting fuel out of the exhaust..

[kaltherzigh]

I guess you should redo this test using 100km/h (something about 60mph) because the drag is directly proporcional to the square of the speed, in english, more speed=more drag=more precise measure

If you would i'd like ^^

Thanks

[srdavis37]

Mythbusters did a segment on this same question. I don't remember the test vehicles used, but windows down was 15% more efficient than using A/C.

Putting a drag on the engine with an A/C compressor is definitely worse than any 'drag' from disrupting the areodynamics.

Of course, no two cars are alike so their design may play a significant role.

[landongendur]

I'll have to watch that episode, as people say it was a good one.

[ScottsMomma]

Wow... imagine that... -_-

Thanks for posting the vid.

[landongendur]

For sure!

[notvalidcharacters]

nice testing, but watching, it becomes apparent that this guy is *alone* in the car. He's driving the freeway and shooting the video at the same time. I hope the video continues rolling when he spins out!

[landongendur]

It definitely takes some skill to drive and shoot at the same time. The real hard thing would be shooting while operating the manual transmission :P but that's just too scary for me.

[zielkerules]

what the bloody kell

[zielkerules]

*hell*

[kickflipjr]

nice test. Do you have a link to this on GasSavers?

[landongendur]

Yeah, I put it under "Metro Aerodynamics" but appearantly nobody noticed :(