2012 Chevy SPARK Cd 0.326

[aerohead]

I worked up these two images of Chevy's little bullet car.For such a short car,and of little aft-body,it seems plenty good as a starting point for low drag.It just needs some length.

[MetroMPG]

It's funny - when this car came out, I recall reading a quote from one of GM's designers complaining, "it's too hard to get good aero from a little car!"

Here it is:

"The Spark's short length impacts the drag in two main ways," explains GM's small-car development manager, Dan Molnar. "First, the grille and windshield are more upright to allow greater passenger space, and second, there's simply not enough length to smoothly guide air around the car."

From: http://ecomodder.com/forum/showthrea...get-23755.html

That GM quote sounds like "we gave up" to me. There are plenty of other small cars that do better. EG. the Mirage has a Cd as low as 0.27, according to Mitsubishi (depending on trim). Yes, it's slightly longer than the Spark, but that's not the only reason it's got better aero.

0.326 is the figure for the EV version of the Spark.
0.36 is the (terrible!) figure for the gas version.

Here's what they did to the EV to make it more slippery:



From: http://ecomodder.com/forum/showthrea...-ev-24141.html

[aerohead]

Here are some Cds from other GM products which lie in the range of the SPARK:
1985 Opel Kadett LS 1.3S.............................................. .... 0.32
1988 Holden Commodore VLSS ........................................... 0.32
1989 Chevy Lumina .................................................. ........ 0.32
1991 Buick Regal .................................................. ........... 0.32
1991 Oldsmobile Aurora .................................................. .. 0.32
1998 Chevy Corvette .................................................. ..... 0.32
2005 Chevy Cobalt .................................................. ........ 0.324
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1975 Oldsmobile Cutlass Supreme ...................................... 0.36
1981 Chevy J-Car .................................................. ......... 0.36
1985 Opel Corsa .................................................. ........... 0.36
1985 Opel Rekord 2.2i .................................................. .... 0.36
1985 Chevy Monte Carlo aerocoupe .....................................0.365
1986 Pontiac Grand Prix aerocoupe ..................................... 0.368
2006 Chevy Tahoe .................................................. ......... 0.36
2007 Cadillac Escalade .................................................. ... 0.363
2011 Chevy Aveo .................................................. .......... 0.36
2011 Chevy Traverse .................................................. ..... 0.36
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Along with Aveo,the SPARK seems to acquit itself drag-wise quite well,when compared to some of their 'longer' stablemates.

[oldtamiyaphile]

Originally Posted by aerohead

Here are some Cds from other GM products which lie in the range of the SPARK:

1985 Opel Corsa .................................................. ........... 0.36

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Along with Aveo,the SPARK seems to acquit itself drag-wise quite well,when compared to some of their 'longer' stablemates.

Same size as an 85 Corsa and no improvement in the case of the ICE. What were GM doing for the last 30 years? The Corsa was a long way from class leading drag even in those days - Citroen's 1986 AX claimed 0.31.

[aerohead]

Well,we're further along the curve since the early days









Perhaps our siblings,parents,aunts,uncles,and grandparents vomited when they went to GM's exhibits of low drag offerings at the North American,Dallas,Los Angeles,etc. Auto Shows,and GM figured,'what's the point?'
Example comment:"We're not about to make the world's most aero vehicle that no one would buy." Rick Aneiros,V.P.,JEEP and truck design,Chrysler Group.