Vortex Generators - Fuel Fins

MLucas · Mar 20, 2013

I know we have talked about lowering our cD number and get the car to be more effecient. Some have talked about adding the AeroTabs to their i-MiEV. I came across these FuelFins on Amazon. They look kind of goofy, but the side profile isn't so bad. I wouldn't put them on the side of my car like in one of the pictures. Does anyone with some knowledge of aerodynamics (Neil?) think these would have any affect on our drag coefficient? I tried finding a web site but couldn't locate one and I looked up on YouTube to see if someone posted something about them, nothing. I found one blogger that mentioned them but it was about installing not using. I hate blowing my money on stupid stuff, so I'm checking to see what you all thought.

http://www.amazon.com/FuelFinsTM-En...Generator/dp/B005BW7ZFK/ref=pd_sim_sbs_auto_8

jray3 · Mar 20, 2013

Ah, a long-running popular debate topic on the efficiency forums!

Here's a couple of good threads that also include alternate suppliers and DIY instructions.

http://ecomodder.com/forum/showthread.php/where-buy-vortex-generator-fins-3889-3.html
http://www.gassavers.org/f11/air-dam-and-vortec-generators-7718-4.html

Some say they only help to improve flow at steep body transitions, like before a sedan windshield and before the rear windshield on a sedan, but not a hatchback. However, AirTab's whole mantra is to stick 'em on the back of squarebacked vehicles. There's a lot of discussion online, but even pseudo-scientific tests are hard to find.
One of the best papers out there is from Mitsubishi itself...
http://www.mitsubishi-motors.com/corporate/about_us/technology/review/e/pdf/2004/16E_03.pdf
Some effects can be counter-intuitive, such as the rear deflectors on old station wagons that kept the rear window free of gunk, but set up huge trailing vortices that added drag.

archie_b · Mar 20, 2013

There used to be a web site, http://www.GreenBumps.com, that sold this item in various configurations. Now if you type in that address it just sends you to Amazon.com. Could be company is no longer in business other than to sell off inventory.

Biggest thing to remember about any type of vortex generator is that they only work at highway speeds. At speeds below 45 mph there is no affect on stability or economy. If you drive your i at highway speeds they will help stability in windy conditions and may improve range marginally.

I used the Aerotab on my Smart and it helped alot in windy conditions but improvement in mpg was very small. For the small cost it was worth the money just for the increased stability.

MLucas · Mar 20, 2013

Thanks for all the information. Probably not worth it. I'm happy with the stability of the i on the highway, just looking for ways to stretch my mileage. It's not that i doesn't have the range I need, its more of a game thing, to see how efficient I can get.

Don · Mar 20, 2013

I think they're kinda like the STP oil treatment of the old days - You can make almost any marketing claim you like because nobody can prove you wrong (or right) with factual data

Remember the thingamabob you clamped around your fuel line which was guaranteed to give you 5% more mileage? . . . . or the swirl thingy you put inside your air cleaner which generated a vortex going down the throat of your carburetor?

We used to joke that if you bought 10 or 15 different things from JC Whitney which were all guaranteed to save you 5 or 10 or 15% of your mileage, pretty soon you'd need to pull around a tanker trailer to capture all the extra gas your car was generating :lol:

The air tabs help (or hurt) the airflow so little you wouldn't see any increase (or decrease) in mileage . . . . so if you like 'the look' - Go for it!

We need to find someone to make a thingamabob to clamp around the positive wire leading to our motor so it can 'align' the electrons so we get more miles per Kwh!!

Don

oahumiev · Mar 20, 2013

archie_b said:
Biggest thing to remember about any type of vortex generator is that they only work at highway speeds. At speeds below 45 mph there is no affect on stability or economy. If you drive your i at highway speeds they will help stability in windy conditions and may improve range marginally.

I used the Aerotab on my Smart and it helped alot in windy conditions but improvement in mpg was very small. For the small cost it was worth the money just for the increased stability.

Been using my air tabs on miev for about a year now, majority of my driving is on highway between 55-60mph, have no noticeable mileage gains but like you, I have noticed more stability at highway speeds. Can it be deduced that the more stable a car feels the more fuel efficient it is?