Just out of curiosity, why does it matter? Are you studying it in school or something?

If you're thinking one = a better fuel economy, you have to also consider the extra weight involved in having four doors, etc.

Just look at the EPA fuel efficiency numbers for each.

 

One of the keys to aerodynamic coefficient of drag is frontal area. The two cars are essentially the same, so that is a wash. The next area to measure would be the air going over the roof. Because of the boundary layer of air being attached to the body, the longer sweep of the sedan roof would give ever a slight advantage.

The last area to look at is the rear deck. Because the coupe rear deck swoops down while the sedan has a higher deck with more of a Kamm effect, I would again give the nod to the sedan.

Finally, for just aerodynamic numbers, the lower sedan spoiler would probably show better aero numbers while the coupe spoiler might give just a little more downforce.

In the end, the differences would have to be miniscule, with perhaps a slight advantage to the sedan due to its longer, gently arched roof and higher rear deck.

I would not buy the car based on which one is more aerodynamic. If that is the deal breaker, then get a G35, which has one of the lowest coefficient's of drag of any car out there today. My '03 G35 Sedan has a drag coefficient of 0.26.

Buy the car based on how it looks and feels to you. I was torn between the coupe and sedan and went back and forth many times before finally getting the sedan. I still have a real soft spot in my heart for the coupe and would love to have one in addition to my sedan.

 

u learn something new everyday..lol

where do u go to measure the drag coefficient

 

The best way to find this out is from published windtunnel tests. Although I don't know if they have ever published them...

 

Thanks guys for your input!

 

this is retarted

 

so is your post .....

its cool when someone brings up a good topic. but its to bad that alot of people are more interested in other things ....

 

neluck finding out the number value to the coupes coefficient of drag?
one of the dudes found out how to figure it out urself (long dragged out test)
but i wanna do that after getting a professional number to test it
if my test runs up within 5% error of the professional number, ill begin a few mods and see what helps
they include:
lightweight rims
lower an inch
cover underbody with aluminum plating (to prevent bumper drag and front drag)

and nething else i can think of lol
let me know if u find a professional number

 

The coupe has a lower roofline so it will have less drag, but the amount is probably very small. They have different spoilers because the 4 door was intended to be more toned down and less flamboyant (cliche) than the coupe.

 

yea does anyone actually have the frontal area and coefficient of drag for the FA5, ive been searching for this for a while now

 

ask Honda dealer? or maybe call honda of america and see if they know.

 

The sedan is better. If you want real info, search civic hybrid sites, they have tons of info there.
Hybrid has the decklid spoiler, which helps, then it has those flat wheels, which help, then it has underbody panals, which help more.

 

i bet it would be less if we took the wing off.

 

Frontal Area and Drag C-efficient

I downloaded a performance measuring application for my iPhone "Track Day". It required the frontal area and the drag co-efficient. I have both a 2009 Honda Civic Coupe and a 1997 Miata so I did a search on the Internet. The Civic coupe is listed as 2.237 sq meters and 0.27. I don't remember the exact source but I checked several. The Miata was 1.829 sq meters and 0.38.

 

HELLz yeah man! id go talk to sales people at the dealership just to stump them. =] sounds fun

 

These are all 2006 model numbers:
Hybrid: 0.27 (wiki)
Sedan: 0.31 (wiki)
Coupe: 0.34 (2006 model launch tech data)

The Hybrid has underbody aero worth the extra 0.04, and the coupe's tail costs it 0.03. The spoiler on the sedans after 2008 is to reduce drag, the spoiler on the base coupes is to reduce lift it has little effect on drag.

Honda released a DX-GA model in Canada in 2008 that used the Hybrid's underbody covers, the Dunlop SP31's, and switched to the electric steering. They did this to qualify for a government backed incentive program that gave cash back for cars rated at 6.5L/100km or less.

-SWRT

 

These are all 2006 model numbers:
Hybrid: 0.27 (wiki)
Sedan: 0.31 (wiki)
Coupe: 0.34 (2006 model launch tech data)

That's actually a huge difference, Just like MPG when 31 or 34 might not seem like that much until you realize it's almost 10%, and every 10th time you fill up it would be for free.

I am really surprised if those numbers are correct that the sedan is 9-10% more aerodynamic.

Another thing is that I wonder with the sedans if the difference between the 08s and 09s with the extra cut outs in the bumper makes it better/worse? One would think that even though it's not as nice to look at because it's a vast sea of plastic, the outer edge of the 06-08's lower bumper is probably better for airflow.

 

Sorry to resurrect, but...
Anyone got figures for the 2010?

 

you can also calculate terminal velocity by solving sqrt(2mg/pACd)