GM: Chevy Volt's Cd is 0.28, Prius is 0.30 (tested in multiple tunnels), EV1 is 0.21

[NeilBlanchard]

Hi,

I wonder why the Honda Insight II went from 0.28 up to 0.32? They don't offer the fancy wheels, do they?

I thought I heard that the mirrors used to be ignored for the frontal area (on all cars?) so maybe the "old" methodology also left them of for the Cd tests? Or, may they (Honda and Toyota) tested an earlier prototype, and covered the difference in the CYA "we reserve the right to change without notice..."?

[Frank Lee]

I wonder what changed with test methodology between EV1 and today

[cfg83]

NeilBlanchard -

Originally Posted by NeilBlanchard

Hi,

I wonder why the Honda Insight II went from 0.28 up to 0.32? They don't offer the fancy wheels, do they?

I thought I heard that the mirrors used to be ignored for the frontal area (on all cars?) so maybe the "old" methodology also left them of for the Cd tests? Or, may they (Honda and Toyota) tested an earlier prototype, and covered the difference in the CYA "we reserve the right to change without notice..."?

That's what I thought too. I'm starting to think the auto manufacturer Cds are just pre-published Cds. They aren't a basis for comparison.

CarloSW2

[NeilBlanchard]

Hi,

Some other possible explanations are that GM retested the EV1:

Without the battery installed, and the unweighted suspension caused the increase of 0.02

Or, they tested the EV1 without the rear wheel skirts -- because those are not offered on the Volt?

And despite GM's attempt to spin this; the EV1 is still an order of magnitude better, IMO.

Try this on for size:

The 1937 Schlör "Pillbug" had a Cd of 0.13 and carried up to 7 people
The 1939 Maybach had a Cd of 0.16 in a conventional package
The Mercedes "Boxfish" has a Cd of 0.19 and carries 4 people
The EV1 had a Cd of 0.19 and carried 2 people
The VW Up! Lite weighs 1530 pounds and has a Cd of 0.237 and carries 4 people
The Toyota 1/X has a curb weight of just 926 pounds and carries 4 people -- and can go more than 600 miles on 4 gallons of fuel: that's 150mpg+ folks!

Green Car Congress: Toyota 1/X Plug-In Concept Makes North American Debut At 2008 Chicago Auto Show

The 1/X has a 500cc plug in (serial?) hybrid that has about as much room as the Prius, but weighs 1/3 as much, and guess what? It triples the FE of the Prius.

The Volt is pretty disappointing GM! It weighs in at a very porky 3,500 pounds, carries 4 people, gets ~42mpg, has a Cd of 0.28 (maybe!) and it costs more than $40K -- and will sell at a loss...

[instarx]

I'm no GM fan, but what's with all this "GM, the Great Satan"? Remember, they did tell you which model Prius they tested, and they didn't have to do that. When doing comparisons on anything, cars to apples, it is necessary to control as many variables as possible, so comparing a Prius with 17" wheels with a Volt with 17" wheels is actually more experimentally correct than deceitful. They compared cars that were as alike as possible and that is the way it has to be done for the results to have any validity at all.

Some of you are actually to the point of making things up out of thin air about how they "probably" fudged the results.

[sprkthead2]

You guys should check out Chevrolet Volt group in facebook. They consider the Volt an electric car not a plug-in series hybrid.

[tasdrouille]

Mirrors are included in the definition of frontal area.

Originally Posted by sprkthead2

You guys should check out Chevrolet Volt group in facebook. They consider the Volt an electric car not a plug-in series hybrid.

They are trying to spin the definition around. It really is a series hybrid, but it is also a range extended EV. It's just that the term "serial hybrid" was there before. To me it's one and the same, but GM seems to want to put some distance between the Volt ant the word hybrid.

[cfg83]

instarx -

I thought of the "experimental controls" aspect too, but the "car on the road" is what the customer will buy. Another way to be more honest would be to do multiple tests and report the comparative results. The OEM Prius as a baseline and the Prius 17s as a second "modified to match the volt" data point.

I think you would agree that the Cd that will be *meaningful* to the customer is the one that uses an OEM platform setup. Technically, the Volt is not yet OEM, so they could have modified *their* configuration to match the Prius.

I *don't* think GM as the Great Satan, with the exception of some members of upper management.

CarloSW2

[NeilBlanchard]

Hello,

Originally Posted by sprkthead2

You guys should check out Chevrolet Volt group in facebook. They consider the Volt an electric car not a plug-in series hybrid.

Frankly, they're just wrong -- how many EV's do you know of that haul around a 1.4L 4 cylinder ICE just for the heck of it? It is a serial hybrid, pure and simple.

[aerohead]

duPont/GM invented style-obsolescence,I guess they're going to stick with 'til the caskets buried.They're already in the grave.