Drag(cw)
09-30-2006, 07:01 AM
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I was wondering how come the drag (cw) from bmw international website is 0.35 for the Z4M coupe, 0.32 for the M6 and 0.31 for the M5?!
I mean shouldn't it be, sort of, the other way around? M5 having the bigger drag because of the shape, then the m6 and then the z4 M coupe wich should be the most "arrowish"?
I mean shouldn't it be, sort of, the other way around? M5 having the bigger drag because of the shape, then the m6 and then the z4 M coupe wich should be the most "arrowish"?
09-30-2006, 11:25 AM
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Bit more complicated than that. Cd also depends shape in strange and mysterious ways, and - believe it or not - a longer car has (all else being equal) a lower Cd.
10-01-2006, 05:40 AM
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Originally Posted by dlevi67' post='340350' date='Sep 30 2006, 10:25 PM
Bit more complicated than that. Cd also depends shape in strange and mysterious ways, and - believe it or not - a longer car has (all else being equal) a lower Cd.
10-01-2006, 11:25 AM
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Originally Posted by BetterMakeWay' post='340533' date='Oct 1 2006, 02:40 PM
Strange though. You'd expect from the Z4 M coupe to be one of the most aerodynamical shapes at bmw...or at least that's my perspective.
10-01-2006, 11:38 AM
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Originally Posted by dlevi67' post='340625' date='Oct 1 2006, 10:25 PM
It's also - of the three there - the most heavily (if prettily) styled. And I suspect the short tail does hurt the Cd.
10-01-2006, 11:42 AM
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Higer performance cars and lighter cars need more downforce to keep them glued to the road surface.
This is incorporated in the design.
More downforce = more drag, that is why there is the difference.
Also why on twisting circuits, race cars use more 'wing' to create downforce at the expense of top speed, due to the increase in drag.
This is incorporated in the design.
More downforce = more drag, that is why there is the difference.
Also why on twisting circuits, race cars use more 'wing' to create downforce at the expense of top speed, due to the increase in drag.
10-01-2006, 12:07 PM
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Originally Posted by KAF' post='340629' date='Oct 1 2006, 10:42 PM
Higer performance cars and lighter cars need more downforce to keep them glued to the road surface.
This is incorporated in the design.
More downforce = more drag, that is why there is the difference.
Also why on twisting circuits, race cars use more 'wing' to create downforce at the expense of top speed, due to the increase in drag.
This is incorporated in the design.
More downforce = more drag, that is why there is the difference.
Also why on twisting circuits, race cars use more 'wing' to create downforce at the expense of top speed, due to the increase in drag.
10-02-2006, 12:36 AM
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Cd is the COEFFICIENT of drag, not the amount of drag. You need to multiply by frontal area to achieve CdA, which is the true measure of drag - by this measure, the Z4 should have the lowest figure, the E60 the highest.
10-02-2006, 12:56 AM
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Originally Posted by hythe' post='340755' date='Oct 2 2006, 11:36 AM
Cd is the COEFFICIENT of drag, not the amount of drag. You need to multiply by frontal area to achieve CdA, which is the true measure of drag - by this measure, the Z4 should have the lowest figure, the E60 the highest.
10-02-2006, 01:17 AM
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Originally Posted by BetterMakeWay' post='340761' date='Oct 2 2006, 09:56 AM
How come? What's the frontal area for each model?