CdA list

[Daox]

Well, I thought it might be nice to get a good aerodynamic comparison going between different cars and CdA is really the only way to get that. So, this morning I threw some data together on an excel spreadsheet and totaled up some of Toyota's smaller cars on it. I'd like to expand it to other brands (I'm most familiar with Toyota) and I would like you guy's help for that. Here is what I have so far.

You can see I sorted it by CdA. The height and width are in inches and frontal are is in square feet (W * H * .81). The formula used for CdA is Frontal Area * Cd.

CdA List

CdA List.xls

[LostCause]

My "area" value is just vehicle width times height, as you seem to have done in your spreadsheet. If anyone remembers the link that describes the GIMP method of finding area, I'll submit a more accurate number.

1996 Ford Thunderbird
Cd: 0.31
Width: 6.0 ft
Height: 4.4 ft
A: 26.5 ft^2

CdA: 8.2 ft^2

- LostCause

[Daox]

Yeah, I suppose frontal area should include the .81 into the calculation. I went through and added a bunch of Scion and Honda data yesterday as well. I'll post up the new sheet in a while.

[Daox]

I just replaced the original jpg so the first post should be updated. I have a bunch of the civic info on the bottom, but I'm not sure if its hatch/sedan so I'm not adding it to the bulk of info yet.

If you know your car's dimensions and .cd and model year range I'd greatly appreciate you posting it.

Of course, if you see any mistakes please let me know.

[Doofus McFancypants]

i just looked online some and a 2000 Nissan Altima numbers are below.
W = 69.1 "
H = 55.9 "

with the 0.81 factor this works out to 21.73 Sq Ft

Cd (per MSN Auto) = 0.32

CdA would then be 6.95 Sq Ft

[tasdrouille]

Make: Hyundai
Model: Elantra
Year: 2007 -
Cd: 0.32 Cd
Height: 58.3
Width: 69.9
Frontal Area: 22.92
CdA: 7.33

Make: VW
Model: Jetta
Year: 1993-1999
Cd: 0.30 Cd
Height: 56.1
Width: 66.7
Frontal Area: 21.31 (per VW)
CdA: 6.39

[Daox]

Excellent. I added the Altima (along with the other generations 1990+) and Sentras. I added Tas's cars as well. If I have time I'll go ahead and get their siblings and add them.

I could really use some help with the Metros and Civics though. I couldn't find good info differentiating between the hatchback and 4 door versions.

[Daox]

I changed the format to html because it was getting a bit long. This way you can also search for what you want. I also posted up the .xls file if you wanted to download and resort it.

[tasdrouille]

There is a double entry for the elantra 2007 -

Also:

Make: VW
Model: Passat
Year: 1995-1997
Cd: 0.31 Cd
Height: 56.4
Width: 67.5
Frontal Area: 21.41
CdA: 6.64

Make: VW
Model: Passat Wagon
Year: 1995-1997
Cd: 0.33 Cd
Height: 58.7
Width: 67.5
Frontal Area: 22.29
CdA: 7.36

Make: Hyundai
Model: Sonata
Year: 2006 -
Cd: 0.32 Cd
Height: 58.0
Width: 72.1
Frontal Area: 23.52
CdA: 7.52

But mostly...you'll thank me for that

[tasdrouille]

Here are some I extracted from the pdf linked in my previous post:

ACURA 3.0 CL 1997
Coefficient of drag: 0.34
Frontal area: n/a
Overall height: 54.7 in.
Overall width: 70.1 in.

ACURA 3.2CL TYPE-S MANUAL 2003
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 55.5 in.
Overall width: 70.6 in.

ACURA NSX 1998
Coefficient of drag: 0.32
Frontal area: 19.16 sq.ft.
Overall height: 46.1 in.
Overall width: 71.3 in.

ACURA INTEGRA TYPE R 1997
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 51.9 in.
Overall width: 66.7 in.

ACURA RSX TYPE R 2002
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 54.5 in.
Overall width: 67.9 in.

CHEVROLET CAVALIER Z24 1997
Coefficient of drag: 0.36
Frontal area: n/a
Overall height: 53.2 in.
Overall width: 67.4 in.

CHEVROLET CAMARO SS 1998
Coefficient of drag: 0.34
Frontal area: 22.00 sq.ft.
Overall height: 51.3 in.
Overall width: 74.1 in.

CHEVROLET MONTE CARLO SS 1999
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 55.2 in.
Overall width: 72.7 in.

CHEVROLET MONTE CARLO Z34 1998
Coefficient of drag: 0.36
Frontal area: 22.60 sq.ft.
Overall height: 53.8 in.
Overall width: 72.5 in.

CHRYSLER PT CRUISER LIMITED EDITION 2000
Coefficient of drag: 0.40
Frontal area: n/a
Overall height: 63.0 in.
Overall width: 67.1 in.

CHRYSLER SEBRING LXI 1998
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 53.0 in.
Overall width: 69.7 in.

FORD ESCORT ZX2 SPORT 1997
Coefficient of drag: 0.36
Frontal area: n/a
Overall height: 52.3 in.
Overall width: 67.4 in.

FORD SVT F-150 LIGHTNING 2002
Coefficient of drag: 0.36
Frontal area: n/a
Overall height: 70.9 in.
Overall width: 79.1 in.

FORD SVT MUSTANG COBRA 2003
Coefficient of drag: 0.38
Frontal area: 22.50 sq.ft.
Overall height: 52.5 in.
Overall width: 73.1 in.

HONDA ACCORD EX V-6 COUPE 1998
Coefficient of drag: 0.34
Frontal area: n/a
Overall height: 55.1 in.
Overall width: 70.3 in.

HONDA CIVIC SI 1999
Coefficient of drag: 0.34
Frontal area: n/a
Overall height: 54.1 in.
Overall width: 67.1 in.

HONDA CIVIC SI 2001
Coefficient of drag: 0.33
Frontal area: 21.40 sq.ft.
Overall height: 56.6 in.
Overall width: 66.7 in.

HONDA CIVIC DEL SOL VTEC 1994
Coefficient of drag: 0.35
Frontal area: n/a
Overall height: 49.4 in.
Overall width: 66.7 in.

HONDA PRELUDE SH 1997
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 51.8 in.
Overall width: 69.0 in.

HONDA S2000
Coefficient of drag: 0.33
Frontal area: n/a
Overall height: 50.6 in.
Overall width: 68.9 in.

HYUNDAI TIBURON FX 1997
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 51.3 in.
Overall width: 68.1 in.

HYUNDAI TIBURON GT V-6 2003
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 52.3 in.
Overall width: 69.3 in.

LOTUS ELISE 1997
Coefficient of drag: 0.34
Frontal area: n/a
Overall height: 47.3 in.
Overall width: 67.0 in.

LOTUS ESPRIT TURBO 1997
Coefficient of drag: 0.33
Frontal area: 19.40 sq.ft.
Overall height: 45.3 in.
Overall width: 73.5 in.

MAZDA MIATA 1998
Coefficient of drag: 0.38
Frontal area: n/a
Overall height: 47.3 in.
Overall width: 66.1 in.

MAZDA RX-7 1993
Coefficient of drag: 0.33
Frontal area: n/a
Overall height: 48.4 in.
Overall width: 68.9 in.

MERCEDES-BENZ CL500 2000
Coefficient of drag: 0.28
Frontal area: 23.90 sq.ft.
Overall height: 55.0 in.
Overall width: 73.1 in.

MERCEDES-BENZ 600SL 1993
Coefficient of drag: 0.45
Frontal area: 21.20 sq.ft.
Overall height: 50.7 in.
Overall width: 71.3 in.

MERCURY COUGAR 1999
Coefficient of drag: 0.31
Frontal area: n/a
Overall height: 52.2 in.
Overall width: 69.6 in.

MINI COOPER S 2003
Coefficient of drag: 0.33
Frontal area: 21.30 sq.ft.
Overall height: 55.8 in.
Overall width: 66.5 in.

MITSUBISHI 3000GT VR-4 1994
Coefficient of drag: 0.33
Frontal area: n/a
Overall height: 49.3 in.
Overall width: 72.4 in.

MITSUBISHI ECLIPSE GS-T 1995
Coefficient of drag: 0.29
Frontal area: 20.40 sq.ft.
Overall height: 51.0 in.
Overall width: 68.3 in.

MITSUBISHI ECLIPSE GTS 2002
Coefficient of drag: 0.35
Frontal area: 20.40 sq.ft.
Overall height: 51.6 in.
Overall width: 68.9 in.

MITSUBISHI MIRAGE COUPE LS 1998
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 51.4 in.
Overall width: 66.5 in.

NISSAN 200SX SE-R 1995
Coefficient of drag: 0.34
Frontal area: n/a
Overall height: 54.2 in.
Overall width: 66.6 in.

NISSAN 240SX SE 1991
Coefficient of drag: 0.30
Frontal area: n/a
Overall height: 50.8 in.
Overall width: 66.5 in.

NISSAN 300ZX TURBO 1990
Coefficient of drag: 0.31
Frontal area: n/a
Overall height: 49.2 in.
Overall width: 70.5 in.

NISSAN 350Z 2003
Coefficient of drag: 0.29
Frontal area: n/a
Overall height: 51.9 in.
Overall width: 71.5 in.

PONTIAC FIREBIRD TRANS AM 1996
Coefficient of drag: 0.34
Frontal area: 22.00 sq.ft.
Overall height: 52.0 in.
Overall width: 74.5 in.

PORSCHE 911 CARRERA (996) 1999
Coefficient of drag: 0.30
Frontal area: 20.90 sq.ft.
Overall height: 51.4 in.
Overall width: 69.5 in.

PORSCHE 959 1990
Coefficient of drag: 0.31
Frontal area: 19.30 sq.ft.
Overall height: 47.2 in.
Overall width: 72.4 in.

PORSCHE BOXSTER 2000
Coefficient of drag: 0.31
Frontal area: n/a
Overall height: 50.8 in.
Overall width: 70.1 in.

SAAB 9-3 VIGGEN
Coefficient of drag: 0.32
Frontal area: 22.20 sq.ft.
Overall height: 56.2 in.
Overall width: 67.4 in.

SATURN SC2 1997
Coefficient of drag: 0.33
Frontal area: 20.90 sq.ft.
Overall height: 52.2 in.
Overall width: 67.3 in.

SUBARU IMPREZA 2.5RS 1997
Coefficient of drag: 0.36
Frontal area: n/a
Overall height: 55.5 in.
Overall width: 67.1 in.

SUBARU IMPREZA WRX 2002
Coefficient of drag: 0.34
Frontal area: n/a
Overall height: 56.7 in.
Overall width: 68.1 in.

TOYOTA CELICA GT-S 1999
Coefficient of drag: 0.34
Frontal area: n/a
Overall height: 50.1 in.
Overall width: 68.3 in.

TOYOTA MR-SPYDER
Coefficient of drag: 0.31
Frontal area: n/a
Overall height: 48.8 in.
Overall width: 66.7 in.

TOYOTA CAMRY SOLARA SE V-6 1999
Coefficient of drag: 0.36
Frontal area: n/a
Overall height: 55.1 in.
Overall width: 71.1 in.

TOYOTA SUPRA TURBO 1994
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 50.2 in.
Overall width: 71.3 in.

VOLKSWAGEN BEETLE 1999
Coefficient of drag: 0.38
Frontal area: n/a
Overall height: 59.5 in.
Overall width: 67.9 in.

VOLVO C70 COUPE 1998
Coefficient of drag: 0.32
Frontal area: n/a
Overall height: 55.1 in.
Overall width: 72.0 in.

[Daox]

Veeeeeeeery nice Tas, and yes thank you!

[tasdrouille]

One thing I noted though. In every single case where the frontal area was stated, the 0.81 correction factor on h * w you used gived an overly optimistic figure.

I recall reading a post by phil, must have been of of his aero seminars I'll have to search a bit, where he said to use 0.87 or 0.85, can't remember exactly.

Edit: it was

Frontal area can be approximated by multiplying your vehicles width times its height,times 0.84.p

from Aerodynamics Seminar # 6 - by Phil Knox

[Daox]

Yeah, I noticed that too. I have updated the calculations to * .84. I have also added the bulk of the list you posted. I still have yet to go through the pdf.

[tasdrouille]

Just so you know, the ones I didn't post left in the pdf are mostly exotics.

[PaleMelanesian]

There's a big list at wikipedia that can fill in some blanks.

[boxchain]

CHRYSLER PT CRUISER LIMITED EDITION 2000
Coefficient of drag: 0.40

FORD SVT MUSTANG COBRA 2003
Coefficient of drag: 0.38

MAZDA MIATA 1998
Coefficient of drag: 0.38

VOLKSWAGEN BEETLE 1999
Coefficient of drag: 0.38

[SteveP]

A lot of the CdA figures floating around are estimates based on what the estimator thought the Cd might be. Many of the Wiki figures came from the mayfair company website which took a lot from an old version of the cartest program as well as (apparently) estimating a bunch. Accordingly it is hard to say how accurate these are.

I think it would be very helpful if there were some indication in the spreadsheet of where the data came from and whether it is a mfr's number, an independently tested number, or an estimate (and which part, Cd or A or both were estimated).

I'd be interested in knowing where the nology folks got their numbers from.

Without this info it seems like we're really not going to have very good data.

--Steve

[Daox]

Well, its definitly no Bible. But, its a heck of a lot better than nothing. Most of my info that I wasn't sure about I double checked against multipule sites. That being said I have used info from tons of different sites since I pulled most of the info from google. Frontal area is definitly estimated, so this really is a 'best guess'. No offense, I'm not going to go through and source every piece of info. The numbers will vary, but not by that much. You can see generally where your car sits against the pool of cars on the list. So, when someone comes on the site and says they have a frontal area of 19ft^2 you can know that is pretty small.

[SteveP]

Originally Posted by Daox

Well, its definitly no Bible. But, its a heck of a lot better than nothing. Most of my info that I wasn't sure about I double checked against multipule sites. That being said I have used info from tons of different sites since I pulled most of the info from google. Frontal area is definitly estimated, so this really is a 'best guess'. No offense, I'm not going to go through and source every piece of info. The numbers will vary, but not by that much. You can see generally where your car sits against the pool of cars on the list. So, when someone comes on the site and says they have a frontal area of 19ft^2 you can know that is pretty small.

Well, if the goal is just to "see generally where your car sits against the pool" then it might not be worth noting whether the data is wind tunnel or "eyeballed" (to take the extremes). I was just hoping that maybe a little more rigor could be injected by at least noting which numbers came from probably reputable sources vs from "unknown" sources.

Simply checking "multiple" sources doesn't do much--you would need to check independent sources--from what I've seen, a lot of the CdA info on the net is just repeated over and over with the result that very little is independent.

I think your frontal area is better than "a best guess". You've at least documented how the number was arrived at and if someone has a reason to use a different algorithm, they can do so since you provide the raw info (width, height).

--Steve

[aerohead]

Originally Posted by tasdrouille

One thing I noted though. In every single case where the frontal area was stated, the 0.81 correction factor on h * w you used gived an overly optimistic figure.

I recall reading a post by phil, must have been of of his aero seminars I'll have to search a bit, where he said to use 0.87 or 0.85, can't remember exactly.

Edit: it was from Aerodynamics Seminar # 6 - by Phil Knox

.84 was from "ancient" text,and Hucho's more current 0.81 multiplier reflects the industry use of more tumblehome in modern rooflines.I've glanced at a few semi-current CAR and DRIVER mags and they're reporting some "official" frontal areas that work out in the ninety-percent region,further confounding the likes of aero-modders in search of accutate quanta.Rats! I used to be more current,had subscriptions and everything.I got turned-off by all the paid advertising and let all my subscriptions lapse.Sorry!