05-29-2014, 08:47 PM
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#1 (permalink)
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Master EcoModder
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Car & Driver Aerodynamics Test
This is great! Mainstream car magazines are picking up on what we already know: aerodynamic drag is critical to car efficiency.
http://www.teslamotors.com/sites/def...n-the-road.pdf
Aerodynamic Tesla Model S Electric Car Wins The Wind-Tunnel Wars
Wind tunnel contests! 
Bring 'em on!
Quote:
Interestingly, only the Model S and Volt lived up to their official drag coefficient numbers, of 0.24 and 0.28 respectively. The Prius missed out by a hair, at 0.26 compared to an official 0.25.
The Leaf, Mercedes, and old Insight were all significantly higher than their official figures, however.
Nissan's car returned a 0.32 figure in the wind tunnel, against an official 0.28. The Insight should have matched the Prius at 0.25, but came back at 0.30, and the CLA matched that figure--missing out significantly on its official 0.23.
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The Following 13 Users Say Thank You to NeilBlanchard For This Useful Post:
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aerohead (05-30-2014), California98Civic (05-30-2014), Cd (05-30-2014), Frank Lee (05-29-2014), Insight for life (05-29-2014), JRMichler (05-30-2014), mcrews (05-29-2014), mikeyjd (05-29-2014), PaleMelanesian (05-30-2014), sendler (06-06-2014), Superfuelgero (05-29-2014), whatmaycome14 (06-01-2014), Xist (05-29-2014) |
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05-29-2014, 10:06 PM
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#2 (permalink)
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(:
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More proof we shouldn't get too hung up on small published Cd variations; who knows if they're accurate anyway?
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05-29-2014, 10:16 PM
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#3 (permalink)
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Not Doug
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How is the Insight worse than the Prius?
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05-29-2014, 10:50 PM
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#4 (permalink)
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...beats walking...
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I'm more inclined to think the "differences" could be the result of 'static' (no tires rotation) versus 'dynamic' (dynamometer) wind tunnel testing techiques. Spinning wheels create eddy currents which create a LOT of drag!
Last edited by gone-ot; 05-29-2014 at 11:16 PM..
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05-29-2014, 11:32 PM
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#5 (permalink)
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Moderator
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The guys at Green Car Reports should read Road & Track once in a while--they were the only publication I know of to accurately report Mercedes' claimed drag coefficient for the CLA250 (the only version available in the US, in addition to the AMG) of .28, not .23 ( straight from the horse's mouth here).
Last edited by Vman455; 05-29-2014 at 11:38 PM..
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05-29-2014, 11:44 PM
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#6 (permalink)
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EcoModding Apprentice
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.30 for the 2001 insight? uh think again people.
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05-30-2014, 12:12 AM
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#7 (permalink)
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Cyborg ECU
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That CLA number looked bogus from the beginning. Nice to see a test of it. .30 instead of .23! I wonder how much could be innocent variation between testing facilities? Any of it?
__________________
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.
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05-30-2014, 11:18 AM
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#8 (permalink)
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Master EcoModder
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What's with the .30 Cd on the Gen 1 Insight?
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05-30-2014, 12:43 PM
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#9 (permalink)
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Master EcoModder
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Quote:
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The expert in charge at our clandestine test location explains: “All wind tunnels strive to accurately quantify the aerody- namics a car will experience in the real world. The vehicle and the tunnel consti- tute a system with complex interactions. As a result, drag and lift measurements on a particular vehicle can vary from one tunnel to another.”
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They name the cars but they decline to name the tunnel? What are the odds it's A2?
The car that costs 3x as much has better aero? I am shocked. |
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05-30-2014, 01:13 PM
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#10 (permalink)
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...beats walking...
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The *information* that I thought MOST USEFUL was their listing of aero power at 70 & 100 MPH:
14 HP @ 70 MPH; 42 HP @ 100 MPH - Tesla S P85
14 HP @ 70 MPH; 42 HP @ 100 MPH - Toyota Prius (GenIII)
16 HP @ 70 MPH; 45 HP @ 100 MPH - Chevrolet Volt
16 HP @ 70 MPH; 48 HP @ 100 MPH - Mercedes-Benz CLA-250
18 HP @ 70 MPH; 53 HP @ 100 MPH - Nissan Leaf SL
...that's two KNOWN points on their respective aero curves!
Last edited by gone-ot; 05-30-2014 at 03:14 PM..
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