Front Air Dam ABA test results: 7.49% increase in MPG at 60 mph (2003 Honda Civic DX)
 

http://ecomodder.com/forum/attachmen...1&d=1431524204

http://ecomodder.com/forum/attachmen...1&d=1431524204

ABA test today was as follows:

I used the same 4mi. course that I did for my wheel covers. 2mi up, 2mi back, then averaged. Speed was 60mph, windows up, A/C off, radio off, fan on.

(Without Air Dam)
A1: 45.10mpg
A2: 44.45mpg
A3: 44.50mpg
AVG: 44.68mpg

(WITH Air Dam)
B1: 47.80mpg
B2: 48.25mpg
B3: 48.05mpg
AVG: 48.03mpg

(Again, without)
A1: 44.75mpg
A2: 44.6mpg
A3: 44.5mpg
AVG: 44.62mpg

I took the average of the closer results: 48.03mpg is a 7.49% increase over 44.68mpg!

nice! got pics the dam?

Well done! Makes me that much more motivated to make one of my own.

jedi sol: http://ecomodder.com/forum/showthrea...ete-27138.html has pictures.

That is one of the largest improvements that I have seen for almost any modification.

Sounds like my experience with airdams...
I have observed between 5%- 15% increases, between a few differant cars.

Added photos from the build thread.

Thanks for doing the testing - it's time consuming, but worth the effort.

Nice work. Thanks for the report.

Just this morning I realized I'm going to have to test it again after I do full belly pans for front and back to see if it is "needed" at that point. Oh, joy. :)

It actually didn't take that long to take off or put back on, maybe 10min?

Yes, but will you do A-B-A with the belly pan?

I do not think that any of us will blame you if you forgo it.

Got a question. I have a 2012 Chevy sonic turbo sedan. I was wondering if a air dam is better to have than full under body panels? I'm thinking underbody based off of knowledge I have gathered from this site and others. Could some confirm this for me?

Belly pan is most critical under the nose, then under the trunk, with the mid-section least critical, per Hucho. It's reportedly a fair amount of work.

Reportedly, you get more bang for the buck with an air dam under the front bumper. It's comparatively cheap and easy to install, i.e., a few bucks at Ace Hardware or Home Depot for a roll of garden edging, which would do two or three cars. In absolute terms, the air dam may not be quite as good as a full belly pan, but the difference in aerodynamic efficiency is marginal vs. cost and work involved. And, the air dam deflects air smoothly past the front wheels, which are effectively buckets of drag, given the oblique angle of airflow hitting them. (Previously on this website is a revealing wind tunnel picture from Hucho's book, where an Opel Calibra has the front wheels impacted by airflow at an angle of about 60 degrees:

http://www.google.com/imgres?hl=en&b...7&tx=132&ty=95

Anyhow, given such flow around the nose of an unfaired vehicle, the air dam seems a cheap and effective way to shunt a lot of draggy air past the wheels, and keep it from building up under the draggy underbody of the vehicle.

It might be even better to combine air dam and undertray, and/or fairings in front of and behind each wheel, per Prius et al.

Sporty Modder described it well in http://ecomodder.com/forum/showthrea...tml#post393469

Thank you for the info. I'll be looking into the sporty mods form.

In my experiance, 6+ cars with airdams, I have gained 5%-15%. Worst is my b4000 1mpg for a 19mpg truck, best was my previous Lincoln Town Car, 3+ mpg on a 23 mpg car.
My Celica is avg with about 8%, 2mpg with a 26 mpg car. it is going to get a front belly/splitter and a better designed airdam.:D
Let me know if you have any questions about airdams.
http://ecomodder.com/forum/showthrea...gts-21369.html

Yeah, probably not! Wouldn't that be something though...

I wouldn't mind spending a little extra time and money for better results. Car currently just got 57 mpg going from Houston to San Marcos averaging 60 mph. Cars current mods are lowering springs (two inch drop), put mesh behind the grill to help protect from rocks and decrease some air going into the engine bay. So if I was to only see a 5% increase from a underbelly that would actually be very nice.

I wonder how low is too low? I just put on a landscape edging air dam, and since my car is so low already, it's about 1~2" off the ground.

That's my problem. The stock air dam on my car won't even allow me to drive over a shoe.

The one on my town car was about 3" off the ground, It would scrape the ground when I would brake, and when I travelled in the lanes with deep tire grooves.

Hot rod says scrape the ground, i think it was bamzippow did that with belting on his truck.

I've actually decided that scraping isn't really a bad thing (at least with garden edging). It hasn't been damaging my mounting points and thus far it looks like nothing bad has happened as a result. So... who cares, right?

Right. Mine has scraped on some speed bumps and almost always on my own driveway--for years now. The lawn edging bends and snaps back. It is very durable. But over time, it has worn one or two mounting points, and I have had to repair. Extremely minor. Done in a couple minutes.

It's only scraped a couple of times since I installed it. At the bottom of my driveway, twice, when I was going down it fast, and when I pulled out of a parking lot fast across a gutter. I thought it would scrape on everything, but it hasn't. Mostly I'm wondering if too low will hurt aero, but I haven't been able to get a good run down the roads I frequent to be able to judge it's effect. It was super windy yesterday and rainy today, both would skew a informal test. It does seem to have better front down force and less body lift at speed, though.

the pics have disappeared! please repost them

I'm all in favor of scientific procedure, but not to the extent of undoing something as universally proven as an airdam. Too much work for no tangible reward. Then you have to reinstall it, even more work you could have just left alone. Plus the waste of time you could have spent on the undertray, enjoying even more MPG, so your removing it actually cost you even more $ than you thought.
You do want the tray sloping up from the rear axle up to the rear bumper.

FYI:

I've uploaded pics of the dam in question from the photobucket stream to post 1.

what is the current ground clearance of your airdam? also how far does it extend from the bottom of the bumper? out of all these air dams your one looks like it would suit my car best!

I am sure he'll add his info when he returns next to this site, but my car and airdam are quite similar in materials and dimensions. I went out and measured: I have 13" wheels with 165/70 tires (slightly shorter than stock wheel/tire diameter) and my airdam's clearance from ground is 10.5cm and its face is 9.5cm tall.

That's dam nice!

excuse the pun!:p


what was your results with the airdam? my cars front bumper sits a bit higher but I think im going to keep the face same as yours but bring it lower towards the edges to deflect more around the wheels

I don't recall ever testing, because it had been tested many times by others. I just selected one of the best designs, modded the thing to my needs, and went with it. The butt-dyno suggests it makes a big difference. I consider it one of the most effective mods possible. And it is so cheap and easy!

Can anyone provide any advice of whether a front air dam would benefit my Fabia?

My Skoda Fabia has a very small OEM damn (no more than an inch) which sits just ahead of an OEM undertray that seals off the bottom of the engine bay nicely. The car also sits on stock suspension so the ride height is typically hight of a eco hatch back.

Would a front air dam only increase the frontal area of the car? My understanding is you want to decrease the flow of air through the turbulent underbody, but would that need to be a balanced trade off with frontal area, no?

Sorry, many questions, and no pics at the moment.

Fabia
 

I looked up your car online,here's a technical drawing:
http://autoautomobiles.narod.ru/auto...koda-fabia.gif
I don't see any measurable benefit that you'd derive from a lower airdam unless you were going to race it only.It looks as if it's already optimized for drag.
A number of aerodynamicists who've done wind tunnel and CFD investigations found that as length was added,the drag benefit disappeared,reversing the trend,unless very close to the ground,which won't work for a daily driven car.
Volkswagen tested about 18-different air dams for their VW do Brasil 1600 fastback.There was nothing intuitive about the lowest drag configuration tested.Location,geometry,and size all contribute to the interaction.

RS's motor is a 'combi'

http://autoautomobiles.narod.ru/auto...abia-combi.gif

Would that change anything ?

P.s. my Fabia had a lower rubber air dam.

Unfortunately I removed the air dam a while back and have no way of answering this questing exactly. However, if I recall correctly, I had about 4" between the bottom of the dam and the ground.

The air dam is just using the standard lawn edging from Lowes or home Depot. I might suggest that you go and measure what they have before installing anything on your car. Just to play it safe.

why on earth did you remove it? im going to attempt to start my mods this weekend.

This is why, lol

http://ecomodder.com/forum/showthrea...tml#post480625

my bad! didn't realise same person

Thanks, I don't know how I missed that thread.

No offense to our great ecomodder community, but a lot of good threads go unnoticed because of weird ass "thread titles" LOL