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Industry-leading drag coefficient boast...well, it was good while it lasted.

Apparently the new 2014 MB CLA250 has a drag coefficient of .23

(and a hell of a nice looking car for under 30k to boot!)

http://www.motortrend.com/roadtests/sedans/1301_2014_mercedes_benz_cla25...

Comes out in Sept., so I guess we have another 8 months or so of leading the field in that department left.

I'd trade them all for ventilated seats.

@DouglasR | JANUARY 31, 2013: When you plug in your numbers to the jurassictest site, does it increase or decrease the Model S range? By how much? Do you think your estimate is better than the one on the site?

It decreases the range. Jurasic has SCx as 0.5. When using 0.64, a sample 115mi trip from Tucson, AZ to Phoenix, AZ going at 75mph went from 51.7% battery remaining to 44%. I can't say if my estimate is better, but it's more conservative. I would have to "calibrate" the numbers by actually going on a known route and seeing what the actual power usage is.

@kkiri7 | JANUARY 31, 2013: @DTsea,Nice to see a fellow aerodynamicist on the forum. @Alex K, and @Timo, are you also in this field?

Sorry, not me. Just didn't have anything better to do at the time.

@Alex K

Any idea where Jurassic got its numbers?

@DouglasR | JANUARY 31, 2013: Any idea where Jurassic got its numbers?

No idea. They haven't updated their web app in a long time and some of their numbers (weight of car) are not correct. It's always a pain when restarting the web app to go in and change all the numbers to correct values. I am tempted to spend some time and rewrite the app and make it pure Javascript rather than Flash based. The hardest part is getting the elevation information for a given route and that is actually quite easy as Google has an API for that and a sample app (http://blog.programmableweb.com/2010/03/25/google-launches-maps-elevatio...)

@kkiri7, same as Alex K, I just had too much time in my hands.

@Alex K

If you rewrite that app, I'll buy it. particularly if you can add in a parameter for outside temperature (see http://www.teslamotors.com/goelectric#range). :)

There was a moment a year or two ago where they reported a Cd of .225, but I guess final production was a bit more turbulent.

I think they might have been hoping to get away with the camera side mirror replacement they showed in the X. Or maybe they were counting the now-cancelled aero wheels.

It gets better. VW jut green lighted the XL1, a two seater that uses less than 1 liter to go 100Km (it gets 261 mpg). It's a 2cyl diesel hybrid. Drag coeffecient of 0.189. Made or carbon reinforced plastic. Very cool.

That should be 'just green lighted'
Here's the link
http://www.vwvortex.com/news/volkswagen-news/volkswagen-xl1-gets-green-l...

the relevant number in the report is 160 Wh / mile ( 0.1 kWh / km ). Model S is about 320 Wh / mile. So there is room for improvement.

That's a tiny 2-seater; no comparison. Quantity? Price?
But VW certainly pulled out all the tech stops! Used its deep pockets and resources to the full.

VW XL1 = Honda Insight + 20 years.

More like VW XL1 = GM EV1 +20 years. Look at it, it looks almost exactly like EV1.

No comparison in efficiency either, Model S is big five-seater car which means a lot bigger air drag even if it had same Cd, it is heavier, using materials people are actually able to purchase and it get five star safety rating, which I don't believe that VW does.

How many will be made and sold, for how much $$? Is this pricey vapourware?

Well it's cool that they got a great cd, but I don't really think Mercedes look very good on the outside, even this one. The inside is just plain ugly.

I wouldn't dismiss it... you can always learn from your competition. This will be - if at all - a hand build technology demonstration, like the Roadster was. Given its size the MS is the most efficient EV on the road today, but this shows us a little the path to Gen3. Good ideas you take and make your own, for the expensive stuff you find a more cost efficient alternatives. Gen3 large option: 240 W/m with 60 kWh battery gives you 260 m EPA - perfect for the then deployed super charging network (MS owners already paid for it).

The MB is a pleasant looking car. I am skeptical of it being slipperier than the MS. Does it have a full belly pan, or is it a tangle of pipes and plumbing? Whatever the cd numbers, if both are put in the same wind tunnel at the same time, I'm betting on the MS!


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