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Drag coefficient
Donny Dog
 

Posts: 773
Joined: Feb 2012
Location: United Kingdom
Post: #1
Drag coefficient

I happened on the drag coefficients for the various versions of the Evoque, and was surprised to discover that the five-door is marginally more 'slippery' than the Coupe (0.35 versus 0.36). I'd have thought the lower and ostensibly sleeker Coupe would have had the edge.

Theoretically, same-engined five-doors should be a tad more fuel efficient!
09-05-2012 01:47pm
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smayo
 

Posts: 188
Joined: Feb 2012
Location: Birmingham
Post: #2
RE: Drag coefficient

Donny Dog, did the info you found give any difference for the Dynamic with it's little rear spoiler?
Probably makes didly squat difference.

Ordered 17/2/12 Dynamic SD4 Auto 5dr, Mauritius Blue, Pan roof, 20" style 6 (gloss black), Vortex, Ebony Headlining, Ent Pack, Heated St. Wheel, Homelink, Pr Glass, Auto Dim r.view mirror, spare wheel
(This post was last modified: 09-05-2012 01:59pm by smayo.)
09-05-2012 01:59pm
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PhilSkill
 

Posts: 3,880
Joined: Jun 2011
Location: Warwickshire
Post: #3
RE: Drag coefficient

Intriguing it's better, must be an effect of the sloped back roof? , 5dr is also 30kg heavier so probably cancels that out.

MY12 Fuji Dynamic SD4 Manual, Pano Roof, Electric Tailgate with own Close module
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09-05-2012 02:04pm
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Donny Dog
 

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Location: United Kingdom
Post: #4
RE: Drag coefficient

(09-05-2012 01:59pm)smayo Wrote:  Donny Dog, did the info you found give any difference for the Dynamic with it's little rear spoiler?
Probably makes didly squat difference.

It didn't distinguish, it just gave drag coefficients for five-doors versus coupe.


(09-05-2012 02:04pm)PhilSkill Wrote:  Intriguing it's better, must be an effect of the sloped back roof? , 5dr is also 30kg heavier so probably cancels that out.

Good point! Coupe drivers probably have heavier right feet, though, so maybe that cancels the rest out!!Laughing
(This post was last modified: 09-05-2012 02:10pm by Donny Dog.)
09-05-2012 02:06pm
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PhilSkill
 

Posts: 3,880
Joined: Jun 2011
Location: Warwickshire
Post: #5
RE: Drag coefficient

Maybe those bonnet scoops on the Coupe cause drag!

Official MPG and 0-60 of 5dr and Coupe are identical.

Auto's are lower geared so has better accel, but lower top speed, unless lower top speed is part due to losses in the gearbox.

Makes me laugh TD4 and SD4 have identical MPG and yet have different 0-60 and top speed, Which shows the MPG figures are done using the same part of the mapping, which can't be using any of the improved power parts of the maps as they would require more fuel and thus worse mpg...

MY12 Fuji Dynamic SD4 Manual, Pano Roof, Electric Tailgate with own Close module
[Image: 124529.png][Image: 1004887.png]
09-05-2012 02:28pm
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Kimv
 

Posts: 340
Joined: Jan 2012
Location: France
Post: #6
RE: Drag coefficient

My vote is on the boundary layer detaching more easily due to the more sloped roof and thus inducing more drag Smile.
This and:

Since: Drag Coefficient = (2F)/(pv²A) in which A = reference area.

One could conclude that the smaller the reference area, the higher the Drag Coefficient. For cars they use the projected frontal area as "A" btw...And I suppose that since the coupe is lower, the projected frontal area is smaller...

Dynamic SD4 Auto 5dr, Tech Pack, Santorini Black, Verve Interior with Ebony headlining, Panoramic Roof, Privacy Glass, Solar Attenuating Glass, Style 7 Alloys, Adaptive Dynamics.
(This post was last modified: 09-05-2012 03:40pm by Kimv.)
09-05-2012 03:22pm
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pureevoque
 

Posts: 339
Joined: May 2011
Location: solihull
Post: #7
RE: Drag coefficient

That's what I was thinking ! Thud

ed4 Pure 5 Dr, Fuji, Xenons, Front Fogs, Power mirrors & tailgate, 20" Style 6. Ordered 290611 Delivered 090312
09-05-2012 05:18pm
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cjfp
 

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Post: #8
RE: Drag coefficient

I think it's because Coupe owners all have a larger grin that 5dr drivers ('cos they know they made the better choice) and hence more drag as the wind whistles past the teeth!

Pure 3dr SD4 Tech Man ; Firenze Red ; 19" Style 3 ; Pano ; Ebony / Ivory Int ; Auto dim rear view ; 2 seats ; Park Aid - Rear cam ; Ext. folding mirrors ; Adap Xenon ; Fogs ; Mud Flaps ; Side Steps - Rec'd 28/12/11 - Sadly going 6/6/14 - Gone, now running BMW X6
09-05-2012 05:22pm
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Donny Dog
 

Posts: 773
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Location: United Kingdom
Post: #9
RE: Drag coefficient

(09-05-2012 05:22pm)cjfp Wrote:  I think it's because Coupe owners all have a larger grin that 5dr drivers ('cos they know they made the better choice) and hence more drag as the wind whistles past the teeth!

Higher smug coefficient, you mean? Laughing
09-05-2012 05:44pm
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PhilSkill
 

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Location: Warwickshire
Post: #10
RE: Drag coefficient

(09-05-2012 03:22pm)Kimv Wrote:  My vote is on the boundary layer detaching more easily due to the more sloped roof and thus inducing more drag Smile.

I'd go with that.

(09-05-2012 03:22pm)Kimv Wrote:  This and:

Since: Drag Coefficient = (2F)/(pv²A) in which A = reference area.

One could conclude that the smaller the reference area, the higher the Drag Coefficient. For cars they use the projected frontal area as "A" btw...And I suppose that since the coupe is lower, the projected frontal area is smaller...

Now is the coupe lower... it tails off more at the rear, the front components are the same except bonnet, so maybe windscreen slope is not so high? Or does it start further forward and slope back more...?

Still it's irrelevant as the 5dr owners got to their destination while the coupe owners were waiting for their passenger to get in the back! Laughing

MY12 Fuji Dynamic SD4 Manual, Pano Roof, Electric Tailgate with own Close module
[Image: 124529.png][Image: 1004887.png]
09-05-2012 08:28pm
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