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Old 08-27-2013, 11:28 AM   #264 (permalink)
HypermilerAX
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Join Date: Apr 2011
Location: Southern France
Posts: 159

AX - '95 Citröen AX

307 - '04 Peugeot 307 SW
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Quote:
Originally Posted by Sven7 View Post
With Kammback

1:01.2
1:00.6
1:00.5
1:00.9

AVERAGE- 1:00.8

Without Kammback

1:03.4
0:57.1
0:57.2
0:58.6

AVERAGE- 0:59.1

That works out to be a 3% increase in coasting time with the kammback. Does that mean it's a 6% drag reduction?
You can't determine the drag reduction just out of the increased costing time. I made an excel sheet to calculate the Cd with a coast down test.
I don't know the exact values for your car but I took :
m = 1100 kg
Cr : 0,010
A : 1,9 m²

The result is -0,022 for the Cd. I can give you the result with the actual values of your car.

edit : Must have done something wrong. Change is more around -0,008.
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Citroën AX 1.5 D 430.000 km
Peugeot 307 SW 2.0 HDI 136 195.000 km

Last edited by HypermilerAX; 08-27-2013 at 03:16 PM..
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