Friday Evening Question (No, this isn't a thing... yet)

"JayZAyEighty thinks C4+3=C7" (jayzayeighty) 10/25/2013 at 20:01 • Filed to: Friday Evening Question, countach, boxy, aerodynamics, sleek, feq

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Nighthawk's Countach post got me to thinking, since the Countach looks like it has such a low drag coefficient but really has a high one:

What cars that look slippery but really aren't aerodynamic?

It's kind of a hard one, but it would be interesting to hear what people have to say. Also, conversely, the bonus question is:

What cars that look boxy and un-aerodynamic really are aerodynamic?

Bluecold > JayZAyEighty thinks C4+3=C7 10/25/2013 at 18:07

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Aww, smoke for car aerodynamics 'testing'. How quaint.

But seriously, the smoke trail machines are only used for press events.

LuczOr > JayZAyEighty thinks C4+3=C7 10/25/2013 at 18:13

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CTS-V clocks in with a Cd of .31. Boxy looks, pretty good aero.

Just on a side note, drag reduction is an interesting field. A lot of people think that you have to have a very smooth surface to get low drag. Controlling where the flow separates from surfaces is actually more important, as well as reducing the size of recirculating wakes (these things tend to go hand in hand). Just for credibility's sake, here is a photo of my office.

This thing has a Cd of about .51

JayZAyEighty thinks C4+3=C7 > LuczOr 10/25/2013 at 18:16

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Good one, that's really surprisingly low. Thanks for the info, by the way—that seems like a really interesting field.

P.S.- Cool office.

Breakfast Burrito: The True Resident Burrito > JayZAyEighty thinks C4+3=C7 10/25/2013 at 18:18

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Unsurprisingly, though F1 cars look slick, their quest for downforce can push their drag coefficient up to 1.3.

Here's a few with surprisingly low Cd's:

Cd=0.26

Cd=0.28

Cd=0.28

HammerheadFistpunch > JayZAyEighty thinks C4+3=C7 10/25/2013 at 18:20

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W210 E50, looks like a standard 3 box, but it had a seriously low (and still low ) cd of .29. same as a BRZ premium

MikeMeade > JayZAyEighty thinks C4+3=C7 10/25/2013 at 18:21

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I remember being very surprised to hear that a Porsche 914 has a CD of .363. This is crazy low for the era.

Dunnik > LuczOr 10/25/2013 at 18:24

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Very much like that two tone silver/blue with the black highlight stripe, very classic and classy.

04sneaky - Boxers. Blowers. Bikes. And bitches. > JayZAyEighty thinks C4+3=C7 10/25/2013 at 18:27

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Can anyone find out anything on the CD of the Saleen S7? Supposedly so aerodynamic it could drive upside down through a tunnel.

JayZAyEighty thinks C4+3=C7 > 04sneaky - Boxers. Blowers. Bikes. And bitches. 10/25/2013 at 18:31

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Undisclosed :(

But yeah, I can see that!

HammerheadFistpunch > 04sneaky - Boxers. Blowers. Bikes. And bitches. 10/25/2013 at 18:34

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That's not aerodynamic (at least not in this context) since down force causes a boat load of drag. That old "drive upside down" bit...that's an old claim that lots of manufactures like to say. It basically just means that the downforce produced at speed is greater than the weight of the car.

Fred (FreddsterExprs) > JayZAyEighty thinks C4+3=C7 10/25/2013 at 18:40

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Mercedes Bionic concept from 2005. Drag coefficent: 0.19. The average is at about 0.30.

Firewrx234 > JayZAyEighty thinks C4+3=C7 10/25/2013 at 18:56

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Gen 1 beetles had a Cd of 0.48 while an 06 Tahoe had a Cd of 0.39

Edit: the 1996-1999 Saturn SL1 had a drag of 0.315

04sneaky - Boxers. Blowers. Bikes. And bitches. > HammerheadFistpunch 10/25/2013 at 18:58

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Oh I thought this was in reference to both of sorts.

Pitchblende > JayZAyEighty thinks C4+3=C7 10/25/2013 at 19:12

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Audi A2, boxy? Cd of 0.25.

JayZAyEighty thinks C4+3=C7 > Pitchblende 10/25/2013 at 19:14

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Whoa, well done.

Forgetful > Fred (FreddsterExprs) 10/25/2013 at 20:54

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I hear it did a lap of an industrial estate once.

Forgetful > HammerheadFistpunch 10/25/2013 at 20:57

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Any reason you pointed out the premium? I would assume the twins in any package have pretty much the same cd, though I've read that the TRD and other low spoilers are quite good for the flow off the back of the car.

HammerheadFistpunch > Forgetful 10/25/2013 at 23:30

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the limited (with the spoiler) actually has a lower cd at .28

sporkasporka > Breakfast Burrito: The True Resident Burrito 12/27/2013 at 18:19

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the open wheels have a lot to do with that. they completely destroy the Cd. a significant fraction of F1 aero money is spent on managing and compensating for the tires.
more relevant road car/race car drag coefficient comparisons would be LMP1/Datona closed cabin sports car "prototypes"

@oswaldhoogev1 > JayZAyEighty thinks C4+3=C7 02/18/2014 at 12:29

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The Alfa Giulia from the 60s: classic three box design, but a drag coefficient of .33

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