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

[instarx]

I see your point cfg83 - that GM did not pick the most aero 15" Prius model to compare the Volt to, but aren't Prius Vs "on the road" too with OEM 17" wheels? I just don't get the outrage that some have expressed about this comparison. Rather than deceitful it seems well controlled. GM chose the model Prius that most closely matched the Volt's running gear, and to me that seems a fair way to compare the aero of the two body styles.

[orange4boy]

GM's rap sheet is long and sordid. I, for one, will never forgive them for crushing the EV1. (Toyota almost did the same to the RAV4, so I'm not thrilled with them either but at least they relented.)

How about when GM bought up all the light rail in cities across North America and then destroyed them all so they could sell more cars? They were fined $4000 in the anti-trust suit. Cost of doing business. How about the intense lobbying and success at trashing the ZEV mandate?
"Consumers don't want fuel efficient cars" "No wait... we ignored those demands"
"The EV1 has no market, crush it." "No wait.. Crushing the EV1 was our biggest mistake"

I will also call them on their BS when I see it. This is a corporation. Their job is to make money for their investors. Everything else is fair game. Until the corporate structure changes no corporation is your friend. All corporations must be treated with suspicion. The people at the top can make a difference, ethically, but they are few and far between and Lutz ain't one of them.

They have a lot of work to do at building up consumer trust and you don't do that by acting in the same way you did when you lost that trust. They are still fudging.

Base model to base model is a fair comparison. At lest publish that Prius base test so we can make up our minds on our own. If you start changing parts/models to suit your desired outcome where does it end? "We added ballast to the Prius because we don't offer a model as light as the Prius." etc.

It makes you wonder what else they are fudging and that is GM's biggest problem right now... Credibility. They don't have any.

I hope the Volt turns out to be a winner but I have my doubts.

[cfg83]

instarx -

Originally Posted by instarx

I see your point cfg83 - that GM did not pick the most aero 15" Prius model to compare the Volt to, but aren't Prius Vs "on the road" too with OEM 17" wheels? I just don't get the outrage that some have expressed about this comparison. Rather than deceitful it seems well controlled. GM chose the model Prius that most closely matched the Volt's running gear, and to me that seems a fair way to compare the aero of the two body styles.

Your point is well stated. If the engineer had made the same point, then our indignation might be a little more muted.

Because of GM's historic and most recent failures, it's being held to a higher standard than other car companies. It's a dog that's easy to flog. I'm gonna wait and see. I want the Volt to succeed.

CarloSW2

[NeilBlanchard]

The thing that is so amazing about the EV1 is that it had so many good qualities -- it was the FIRST time that GM had designed an electric car! Imagine how good it could have been if they had been refining it, and learning as they went?

I think it was this potential that scared the rest of GM and the oil companies. In a way it was analogous with a small branch of Intel building the first Athlon (instead of AMD) -- it blew by the Pentium II in clockspeed and performance!

The issue about the weight etc. (the EV1 was 2,900 pounds including the 1,100 pound battery), still apply today -- to the Volt! At ~3,500 pounds it will not be a very good electric car. I think that GM is still unable to make up it's mind about "letting" another technology succeed. So, I think they are consciously (or unconsciously?) ham-stringing the Volt so they can make claims on both sides of the argument.

If it succeeds, then they can say "See what we did!" and if it fails, then they can say "See, we told you so!" I think the EV1 was an overall big success (despite the flaws), so they had to kill it to save the rest of their company.

[EngineeringStudent]

Originally Posted by JonnyG

Toyota's website says the 2010 Prius CD is .25 for all versions, even the Prius V with 17 inch wheels. Very interesting how GM is so desperate to look good that they will lie!!!

what's to say toyota didn't fudge the numbers to make themselves look better too? like many things, the truth is probably in the middle.

also, who's to say you can't put moon-disks on the 17" wheels? that way you can have a more stable contact patch and still have a smoother side.

[orange4boy]

what's to say toyota didn't fudge the numbers to make themselves look better too? like many things, the truth is probably in the middle.

You may be right. I bet the CD they give is for their base Prius but that does not justify GM's "fudge". I wouldn't let Toyota off the hook if that were the case but this was GM's story and they could have tested the base but they didn't.

I wish someone would do independent Cd tests so consumers and, more importantly, ecomodders would have consistent info. But then what would we have to debate about?

[EngineeringStudent]

aerodynamic lift, apparently... lol it's a pretty heated topic it seems, but i don't see why.

[orange4boy]

You don't see why? Well. let me tell you young whippersnapper people have been arguing about lift since before you were born. why, my granddaddy used to argue about lift with the wind. All started when he was picked up by a tornado way back in '29...

I think some people just like to argue.

http://www.youtube.com/watch?v=teMlv3ripSM

[roflwaffle]

Originally Posted by MetroMPG

GM is saying that the Cd depends on the wind tunnel (which is apparently true from, what I've read).

The point they're trying to make is that regardless of the absolute figure, their car is relatively better than the Prius*

(* with 17 inch wheels. Gotta love asterixes!)

The wind tunnel config too I imagine. Heck, I bet there are sufficient groups of parameters such that cars within .02-.04 of each other or whatever could flip flop in terms of which one has the best Cd.

[EngineeringStudent]

Originally Posted by orange4boy

You don't see why? Well. let me tell you young whippersnapper people have been arguing about lift since before you were born. why, my granddaddy used to argue about lift with the wind. All started when he was picked up by a tornado way back in '29...

I think some people just like to argue.

that sums it up perfectly lol