Ugly Aerodynamic Tail Makes For Good Fuel Efficiency
Some people will go to great lengths to get the best gas mileage possible. There are simple ways of doing this of course, like using a light touch on the gas pedal and coasting whenever possible. If you’re mechanically inclined you can retard the timing or even perform an engine swap in pursuit of high MPGs.
Or you can add a hideous duck tail to your geo metro. Hey, whatever works, right?
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Forum member MetroMPG, aka Darin Cosgrove, founder of Ecomodder, set the goal of creating a lightweight, easily removable tail to add to his Pontiac Firefly (actually a Geo Metro) to improve the aerodynamics. Improved aerodynamics mean improved fuel efficiency. The tail also had to be easy to disassemble and fit in the trunk of the Metro.
Now the Firefly could best be described as a “bare bones” car, and could easily attain 40 MPG with its Suzuki-sourced 3-cylinder engine by driving gingerly. But it isn’t exactly the most aerodynamic car. But by adding the aluminum, cardboard, and duct tape duck tail, Cosgrove estimates he dropped the drag coefficient from .34 to .23, improving mileage by 15%. He was able to clock in 64 mpg driving at 56 miles per hour. That may sound slow, but I don’t go much faster in my Wrangler because, well… it is a box on wheels and my gas mileage plummets when I go over 60.
While the Firefly isn’t going to win any Concours awards, automakers would be wise to consider improving the aerodynamics of future models. For one, that tail could prove very useful as either a storage hatch, or even better, an engine compartment with the added benefit of improved fuel economy. The Aptera 2e has a similar tail, though gas mileage isn’t so much a concern with an electric car, right?
Would any of you be willing to perform a similar modification to your car to get 60+ miles per gallon? I think I’d rather do an engine swap myself.
Source: EcoModder
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December 31st, 2009 at 11:14 am
My 1989 Geo 4 dr. hatchback gets 53.4 mpg @ 60 mph…(EPA est. 58 mpg-new) 190,000 miles and pulling strong. 1565 lbs. Unmatched these 20 years now.
US automakers can build a “stripper” @ 60 mpg and like the old Metros, will be a big seller to delivery businesses, mail carriers etc. and of course, the economy minded. Geo Metros did very well in our market remember?
December 31st, 2009 at 11:28 am
I’ve owned two Chevy Metros (Geo got merged into Chevy for the 1998 model year) and got 50+ mpg with them. (You have to get the 5-spd manual to get that mileage because the auto transmission is an inefficient 3-spd (doesn’t have overdrive)).
Their value went up quite a bit back when gas was over $4/gallon. They’re still kind of expensive if you can find a good, low-mileage, non-rusty, 3-cyl 5-spd.
Anyway, I like the innovation of the duck tail, but I don’t think I could drive around like that unless I was wearing a bag over my head.
I’ve often thought that semi-trucks could benefit the most from something like that. I’ve even drawn up some ideas for either an inflatable or a tent-like support structure for it. Truckers get anywhere from 3.5-6.0 mpg depending on truck and load. If they could squeak out 1 more mpg, they’d save a fortune.
-Tim
December 31st, 2009 at 11:50 am
“US automakers can build a “stripper” @ 60 mpg and like the old Metros, will be a big seller to delivery businesses, mail carriers etc. and of course, the economy minded.”
They can probably do better now and have more power with direct injection, turbo, variable valve timing, cylinder deactivation, 6-spd transmissions, lighter materials, better aerodynamics, etc. The trouble is all those technologies would bring the cost up to near the price of a hybrid.
“Geo Metros did very well in our market remember?”
It was unfortunate timing for GM/Suzuki that gasoline was at its all-time low all thoughout the 90’s when the Geo brand was just getting going. Then they killed the Metro in 2001. (The same low gas prices sparked the SUV craze that killed my favorite GM platform, the B-body: Chevy Caprice, Buick Roadmaster). Had the timing been such that they were still making Metros in 2004 (when gas first hit $2/gallon) through 2008, they could have sold them for $2500 more per car and they’d have been flying off the lots.
December 31st, 2009 at 5:23 pm
Tim Cleland
Even if it was the price of a hybrid, it would be better.
If I, or anyone else over at ecomodder.com, spent 15k TOTAL on a Geo (or any other high mpg car), we could get 80mpg.
Google Aerocivic, that man has spent about 400 dollars on top of the price of his car and it gets 70mpg.
December 31st, 2009 at 5:26 pm
Hi,
I’m also active on EcoModder, and Darin has been averaging close to 80mpg with this car — without the boattail. And he was in an economy run in August, and he managed 106mpg (which was good for 2nd place) — without the boattail. So, if he builds a more permanent (and slightly refined?) version and get 15% improvement on that, then I call that damn impressive.
The XFI version of the Metro had a different cam, lighter and lower friction pistons, lean burn, and taller gear ratios — if this Firefly had those, it would do even better.
The winner of the economy run BTW, got 118mpg (over a ~104 mile course with ~1,000 feet of elevation change!). His car is a 1989 Honda CR-X HF, with a few aero mods; and very low rolling resistance *snow* tires. http://ecomodder.com/blog/20-yearold-modified-honda-crx-hf-scores-118-mpg-fuel-economy-run/
Sincerely, Neil
December 31st, 2009 at 8:32 pm
The fuel efficiency isn’t worth the ugliness.
January 1st, 2010 at 3:38 am
Disagree with one point at the end – “gas mileage isn’t so much of a concern with an electric car”. In absolute terms of course you’re right, in that they don’t use gas. But they do use energy, and energy in electric cars is the one bottleneck. Energy = stored kWh = installed battery capacity for a given range = potential commercial viability for a useful transport option.
Aptera – 10kWh approx gets 160km
Leaf – 24kWh approx gets 160km
That 14kWh is going to bump the vehicle price by close to $10k.
I think ultra efficient vehicles will be a big step towards the EV transition because they embody the greatest potential for cost reduction. So it kinda bothers me that the group of people seriously developing them is pretty small!
Especially among big auto. The VW L1 is the only variant I’m aware of that seems semi-serious. Sure, it’s got a hybrid drivetrain for now, but plan on changing that.
January 1st, 2010 at 11:42 am
Just wanted to say EcoModder looks like a great website. All different kinds of vehicles being “eco-modded” including a Ford F-150 getting 25 mpg.
I’ve always wanted to make a Chevy Caprice wagon (big roomy 8-passenger vehicle that has almost as much cargo room as a Chevy Suburban) hypermiler and see if I could get it up to 30-35 mpg.
January 1st, 2010 at 7:20 pm
“The fuel efficiency isn’t worth the ugliness.”
I’d say exactly the same about 90% of the guzzlers on the road.
I think efficiency is beautiful. Most people like the looks of aircraft and think they look sexy but put a car on the road that looks like an aeroplane and people think it’s ugly. This is just because people are used to seeing a certain look of car. I think the boattail looks great.
Hats off to someone who cares more about reducing consumption that about how he looks to other drivers.
Nice work, Darin.
January 4th, 2010 at 9:25 am
Form follows function = beauty. Please realize this is a prototype made by one person; who tested it’s aerodynamic qualities, and in no way was it designed as a finished product.
If you think it is ugly; while I can understand this, I think you may be basing your judgments on “normal” cars that have quite poor performance, and that generate all sorts of aerodynamic problems because they are “designed” by stylists, or as a result of a string of design choices that have nothing to do with how they actually function. So, we have many bad habits — both in how cars are designed, and how we judge them.
Sincerely, Neil
January 4th, 2010 at 11:43 am
“The fuel efficiency isn’t worth the ugliness.”
I was feeling that way too upon first reading this article, but after I read the EcoModder article and watched the video, I realized that it was just a test of concept thing. My first reaction to it was a viceral one based a lot on his use of duct tape.
It would probably look pretty cool if it were nicely
finished with a permanent surface.
I have to wonder if the DOT would have anything to say about the safety of the duck tail.
January 6th, 2010 at 9:48 am
1987 Chevy Sprint (aka Metro) 4door, 5 speed…
I loved that car, 63mpg on highway @ 62mph…
Now the gear ratio was too high in the reverse, that you couldn’t back up a hill w/ the AC on. But other than that it was great.
The ‘87 model did not have EFI, but a complex “electronic carb”… a pain to rebuild and re-calibrate. But wow on the mileage!
Why can’t we get past 35mpg today? … it seems we’ve done it before? Loss of memory? Suzuki is still in existence. What’s the problem?
IMHO