Mercedes down to CD of .24 already - .20 in 5 years

For interest, some other coefficients of drag:

GM's EV1 electric car: 0.195

Daihatsu's UFE-3: 0.168

VW's 1-litre car: 0.159

Apart from the EV1, these have not made it into production yet.

 

And it doesn't have door mirrors. Helps with the Cd to be sure, but not much fun backing up.

Is the 2010 Mercedes on sale yet? If not, the Prius is ahead of it.

 

Does anyone have the urban and extra urban cycle numbers handy for the Mercedes E class saloon and the 2010 Prius?

Bob Wilson

 

You should be able to find any information you would like here: VCAcarfueldata.org.uk - Home Page

 

There are 26 distinct specifications of E-Class (model W211), but the new E-Class (W212) isn't yet on the UK government database. Nor is the new Prius, of course.

The range appears to be E 220, E 250, E 350 diesels, E 350 CGI (direct-inject petrol?) and an E 500 petrol. The E 220 is a conventional 5-speed automatic and achieves 34.9/60.1/47.1 mpg(I) presumably with 225/55 R16 wheels. CO2 emissions are 159g/km with 225/55 R16 tyres, 162g/km with 245/55 R17s and 164 with 265/35 R18.

The E 250 has the same basic engine but tuned for more power and torque (though in a narrower range). It's standard with a 6-speed manual though a 5-speed auto is an option. 40.9/64.2/53.3 for the manual, same numbers as the E 220 for the automatic; 139/142/144g/km CO2 for the manual (16/17/18" wheels) and again, same as the E 220 for automatic.

The other cars use more fuel and produce greater emissions, as you'd expect.

3G Prius numbers are 72.4/76.3/72.4 mpg(I), 89g/km CO2 for the 15" wheel, 70.6/74.3/70.6 mpg(I), 92g/km for the 17" wheel, per the Geneva Motorshow brochure.

I'd do it in metric but I can't find metric numbers for the Mercedes.

 

When it comes to Cd, looks can be deceiving.
VW beetle, for example, has high Cd value.
It is difficult to design vehicle that is short to have low Cd value. It is easier for vehicle like LS460 to have lower Cd value. Therefore, for a short vehicle like Prius, achieving Cd of 0.25 is more difficult than for a MB-E to achieve Cd of 0.24. The K-tail of Prius helps a lot in this area.
A K-tail is basically the tail cross-section is roughly 50% of the max cross section. That is a typical K-tail. Think: old Insight, Prius, new Insight. That is why they look so similar.

Yes, getting rid of the side mirrors will help the most. However, I wonder if a car like that will sell today. It just looks weird. It looks like a person w/o ears. Anyhow, maybe we will get used to that someday for the sake of fuel economy and by using camera instead.

 

This is a snippet from Wikipedia on Wind Tunnels:

Other than the fact that Wind Tunnel technology has rather clearly become more sophisticated over time, the skeptic in me has trouble believing the results cannot be gamed, since I doubt a standardized test protocol exists. Same speeds ? Wind angles ? Transition points from laminar to turbulent flow ?

We accept that dynamometry is protocol dependent, but not wind tunnels ?

 

Whaddya mean, it's got smooth hubcaps and rear wheel skirts don't it? Of course it could go that low.

 

Oooooooo

I wonder what the CD was for a 1959 Cadillac with those big ole honkin' fins in the back! I bet Pink was more aerodynamic than Black.