GM Car Czar Bob Lutz dropped quite the load of “Between the Lines” fodder (Justin’s working on it) in his interview with Charlie Rose. One real jaw-dropper: Lutz’s comment that the Volt has a Cd (coefficient of drag) of “between .28 and .29”. Folks, that is seriously bad. Was GM running the wind tunnel fan backwards, or did they put the model in upside down? My 1985 Mercedes 300E had a Cd of .28. As did a 1995 Mitsubishi Diamante. The current Prius scores a .26, and next year's model will undoubtedly improve on that. Lutz specifically said some months ago that the Volt would have better aerodynamics than the Prius. Oh well. Meanwhile, a whole raft of current sedans have a better Cd: Lexus LS430: .26; Hyundai Genesis: .27; Camry hybrid: .27; Mercedes W203: .27; the old B5 Passat: .27. Even the Saab 9-3 ties/beats the Volt with a .28. Keep in mind, that for an EV, aerodynamics plays a much more crucial role in highway range than for a conventional car. That’s why GM’s EV-1 had a spectacularly low Cd of .19. Nothing like progress in the span of fifteen years.
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Now, to be fair, Cd isn’t the only factor in aerodynamics, but it is one of the big ones.
That said, the frontal area of the, ahem, production Volt doesn’t look that small.
psarhjinian: That said, the frontal area of the, ahem, production Volt doesn’t look that small.
My thinking exactly. In fact, this new Delta II platform looks like it was the victim of “bracket creep”; it looks almost Malibu-esqu in stature. Maybe that’s why they’re using last-gen Malibus as mules for the Volt. The wheelbase/width seem to match up.
Bob is just messin with the competion.
You didn’t have to be an aerospace engineer to figure out the Volt they were showing off was about as aerodynamic as a brick outhouse. Also it was huge.
It’s that American styling they probably think they need to get in to re-establish American styling or whatever.
mfgreen40: Bob is just messin with the competion.
Is that what he’s doing, by losing 10 points of market share in the last six years or so? Making quite a nice mess indeed.
I wouldn’t call 0.28 “seriously bad.” But, as you point it, it’s not quite the best.
Nothing like progress in the span of fifteen years.
You’re right; I’ve seen progress in the past 15 years, and this is nothing like it.
“Aerodynamics are for people who can’t build engines.”
–Enzo Ferrari
Or in Maximum Bob’s & GM’s case, electric motors. Can these guys do anything right?
–chuck
.29 is good, if you’re comparing it to an H2.
I mean, even the S-Class does better than that.
Various aerodynamic data can be found at:
http://www.mayfco.com/tbls.htm
If a 1991 Buick LeSabre Limited is a typical car, then we get: Cd=0.36 and A=24.19 ft^2. The important performance figure is the “drag area” — the product of these numbers, or 8.71 ft^2 in this case.
If the Volt had the same frontal area as the Buick, but a Cd of 0.285 (“between 0.28 and 0.29”) this figure of merit would be 6.9 ft^2 or so.
A 2004 Toyota Prius clocks in at 6.24 ft^2:
http://en.wikipedia.org/wiki/Automotive_aerodynamics
I think the Aptera is something like 2-3 ft^2, but can’t find any hard numbers.
In the interview, Lutz also lets on that the Volt concept had a Cd of .43! It utterly defies any logic to build, display and endlessly promote a concept vehicle for a (RE)EV with such a terrible Cd. A gen1 xB, the ultimate brick, has a Cd of .37. The Impact concept, which led to the EV-1, had a spectacularly low Cd.
to summarize mdf’ post: Cd doesn’t mean anything without the cross section. People who compare them typically don’t have any idea what they’re talking about.
Too funny!
I bet Lutz sits back , cold beverage in hand and laughs his butt off.
“Hey Rick! Watch em dance at THIS one!”
Realistically though, the aero benefits at 25-30 mph in city traffic are pretty minimal.
z31: to summarize mdf’ post: Cd doesn’t mean anything without the cross section. People who compare them typically don’t have any idea what they’re talking about.
And you think the production Volt will have a smaller frontal area than the Prius? Not likely. See my comment further up.
Meanwhile, the 2010 Prius will undoubtedly have an improved Cd. I’m guessing about .24. That makes quite a difference at highway speeds.
Bob didn’t take his meds today… and who let him give an interview? Wasn’t it Rick’s turn to watch him?
From the gm-volt.com article:
He said that by next year GM will be producing “substantial quantities” of Volts that are not for sale, and that by next year at this time GM will be able to put “selected media” into driveable Volts.
So they’re going to build “substantial quantities” in 2009, but they won’t be on sale until November of 2010? How does that help GM? He sure is thinking a long way down the road. Maybe GM wouldn’t be so screwed if the executives had been doing that for the last 30-40 years. I can’t see GM lasting until 2009, unless Rick or Bob have a piggy bank that no one knows about.
Oh yeah, the Cd in my ’85 Jetta was .32, and that thing was a friggin’ brick. I can’t wait to see the Volt. I sure hope they manage to build at least one production model so we can all see how great it could have been, had GM not spent all their money on buying out employees. But it’ll probably just be a POS, so whatever.
monkeyboy: “Realistically though, the aero benefits at 25-30 mph in city traffic are pretty minimal.”
And we never leave the city or what?
GM’s been tap-dancing around this for a while… the electric range at low speed may be 40 miles. At highway speeds, GM is thinking it may drop to 32. The worse the drag, the faster that highway range falls off. People with 40 mile commutes (a commute range GM likes to talk about) are going to be pretty unhappy if they’re burning gas every day on that commute because 30 miles of it are at 70+mph (actually quite common here). Not being physicists, they’re going to be thinking, “GM let me down,” rather than, “This is the natural result of operating outside the vehicle’s optimum performance envelope.”
Once the Volt goes out of town, in fact, low drag will be extremely important, as the Volt’s gas tank is reportedly pretty small. If the Volt only gets something like 40mpg at 75mpg due to poor aerodynamics, its overall range is going to be pretty short.
—
A glance at GM-Volt is somewhat amusing. The hard-core Volt fans are jumping for joy and the realists are decrying the mediocre drag score.
Yes, it’s true that you don’t know all you need to know without the frontal area but you still learn quite a bit from the mediocre Cd. A small frontal area to compensate means a more cramped interior. Could be this thing is not going to work out very well for tall people. Or wide ones.
Why will any of this matter? When the volt comes out with a base of $39,900 and delivered with the requisite “packages” at north of $42,000, it will be an also ran at best.This niche has been defined by Honda at $25-30,000. People who can pay the $42-46,000 for a volt can also buy gas for $3.50-$4.00 per gallon. So if they are getting ready to sell 10,000 the first year, that sounds right to me. By that time Honda has retooled, and even Huyndai is out with their iteration of the 25-30K hybrid. This means that all the Asians are selling perhaps 1 million hybrids a year, and GM is ramping up past 10,000. Between the volt and the partial hybrids GM has sprinkled throughout their line, another missed opportunity has just left the station.
You know, the comment about the .28 Cd for the 1985 Mercedes 300E surprised me, as it seemed to be very low. I’m curious to know from where that figure is sourced.
I had remembered that the original Taurus’ Cd was pretty low, and it was out at about the same time. I did some quick internet research on the issue. Here’s what I found.
1) Wikipedia lists the 1986 Taurus as having a Cd of .32. Edmunds says that the original Sable had a Cd of .29.
2) Wikipedia says that the W124, which it says represents the 1984-1995 Mercedes E Class, “had one of the lowest coefficient of drag (Cd) of any vehicle of the time (0.28 for the 200/200D model for European market with 185/65 R15 tires).” Carfolio lists the Cd for the 1985 300E in particular (rather than the 200/200D model) as .30.
Anyone have a definitive source on that issue?
It’s almost like EV’s aren’t ready technologically or something… low range, price so high you’ll never save enough to justify buying it, hmmm.
I am sold! I love the coming Chevrolet Volt. The U.S. needs this car.
On Monday and Tuesday evenings Charlie Rose interviewed Wagoner (CEO), Lutz (project manager), Kruse (batteries), and Boniface (design) at GM. I am rooting for them. I like these guys.
Yes I know Wagoner is paid way too much money, yes I know U.S. car dealers are some of the most despicable creatures on earth, and yes I know the U.S. auto industry didn’t think ahead. So there are plenty of reasons to hate GM and I have done my share of hating them.
But we need the Volt. We need to escape from the tyranny of OPEC and oil companies. We need less expensive and home created energy. We need to stop transferring large amounts of our money to countries with easy to get at oil.
I am also aware that the reason our auto companies didn’t bother to think ahead was because our congress passed incredibly stupid CAFÉ laws and tax laws which in effect subsidized the SUVs and PUs. We now know that we should have raised taxes on fuel at least 10 years ago to fund our roads, bridges, and maintenance and also to discourage inefficient vehicles. The countries of Europe did this. Very easy to see in hindsight.
These 4 GM guys were nice guys and seemed straight forward in their interviews (but I still think Lutz’s take home pay should be cut by 80%).
The article titled “Driven” in the September issue of “Wired” describes countries that are on the verge of adopting Volt type cars for national security and financial reasons. The U.S. needs to do the same. If GM fails and the Volt doesn’t come out there are several other auto companies working on similar cars according to the “Wired” article.
The sad part is my 2008 Prius may be obsolete sooner than I had expected:-)
@folkdancer:
You’re being ironic, right? Please?
Paul Niedermeyer: Meanwhile, the 2010 Prius will undoubtedly have an improved Cd. I’m guessing about .24. That makes quite a difference at highway speeds.
Again, you can’t talk about the Cd alone. The real performance figure is “CdA” — the product of the drag coefficient and the cross-sectional area.
If the cross-section of the Prius remains unchanged, this 0.26 -> 0.24 improvement would take the current CdA of 6.24 ft^2 to about 5.8 or so. Let’s say that Toyota has rounded off some corners and taken CdA down to 5 ft^2.
If (say) 2/3rds of the energy at highway speed is pushing air out of the way, this amounts to a fuel-economy improvement of about 13% or so.
This is a definite improvement, and one anyone should take (it’s like software: the design work is done once, and then stamped out per copy). But it should be put in some perspective: if the 2004 Prius was capable of doing 40 miles on a charge, this range would increase to about 45 miles.
Let’s face it, individual driving style variations will have a bigger impact.
My guess is that the design and engineering people at GM want to build the most efficient vehicle they can. Left to their own devices, they would end up building an Aptera. Maybe one with four wheels?
Which would be fine by me, and probably millions of other people.
But the marketing people at GM are probably at every meeting, and loudly insist the car look vaguely ‘normal’. No doubt someone ran the numbers (as I did, above) and figured that with such a limited range in the first place, it doesn’t matter much, so, why not give baby-boomers the car they are used to seeing?
@folkdancer:
The Volt, by itself, is not going to affect our dependence on foreign oil by a significant amount. Tyranny is a strong word – oil companies are simply successful (in the current market) businesses that deal with huge volumes. They provide a commodity that is used everywhere at an extremely reasonable price – especially considering the complex process that delivers the oil from the the field to your local gas station.
Yes, the government does stupid things that are not in the interest of the public or future generations (surprise!). However, people in the US ultimately have the freedom to choose whatever vehicle they want. Additional taxes are not the answer for two reason: (1) with our quasi free market system, people are already choosing more efficient vehicles due to the increases in energy prices, and (2) do you honestly think the government would use the taxes appropriately?
The countries of Europe do tax the hell out of drivers. Great! It makes driving and living much more expensive. The population density of Europe is much higher than in the states and therefore the average distance traveled per car per year in the EU is much less than that in the US.
The “GM guys” are delusional. Do not drink their cool-aid. While their cool-aid might seem like a delicious and refreshing drink, by the time you are served, you will be disappointed.
I suppose my main points are:
1) the Volt is not going to be as great as GM is making it seem.
2) More taxes? Really? I think the government could save money elsewhere (cough, stupid war).
3) Do not listen to the GM management. The Bob Lutz Award was created for a reason.
I’ve mentioned this before:
My ten year old civic HX gets 40 mpg hwy (it used to get ~43, and then I started driving like an asshole). Sure, it has no modern safety features, but the previous gen civic HX has excellent crash test ratings and supposedly gets 40+ hwy. We do not need $40,000 niche vehicles that have $20,000 of whiz-bang technology to manage 50 mpg. We need vehicles that are simple, efficient, and reasonably affordable. Spend a bit more of R&D funds to reduce weight and tweak aerodynamics, optimize the final drive ratio for mpg’s (damn you, Honda Fit), and call it a day.
Bob says a lot of stuff we dont believe, why should we believe his CD figure?
mdf: Again, you can’t talk about the Cd alone.
Yes I can, because I know what I’m talking about. No, we’re not comparing semis to micro-cars; we’re comparing two cars in the same size class that will undoubtedly have fairly similar frontal areas. And it’s pretty difficult to reduce frontal area when you are building on existing platforms and architecture (Volt is on Delta II platform). Folks don’t want to be in a semi-reclining position, and the Volt has that substantial size battery between the seat; that negates a lower or narrower car. That leaves the Cd as the best opportunity to improve overall drag. And a Cd of .27 – .29 is very…average. Especially when the next Prius will undoubtedly nkock a couple of points off its Cd.
Read this if you want to learn how much GM technology and “expertise” went into creating the GM Impact, the predecessor of the EV-1……
http://www.acpropulsion.com/car_that_could.htm
PN: “My 1985 Mercedes 300E had a Cd of .28”
Actually, it probably had a Cd of .0. There was no 1985 300E. Introduced as an ’86…
The 190 had a Cd of .32+. I imagine the 300E could approach .28 if it was cruising comfortably some three inches behind the trailer of a semi truck.
Seriously, though: does the .28-.29 cited really warrant the dropping of one’s jaw? Really?
As you mention the current Prius scores slightly better at .26, and you seem to make the assumption that the next generation (which will reportedly be a bit larger) will better that. OK, let’s assume they get .25.
I would humbly posit that the difference between the cited Cd ‘s doesn’t warrant the outrage. We simply don’t have enough information. There’s a lot more information needed to start evaluating rolling load force for these two platforms. Information that we don’t have, presently.
I hope these comments are taken as constructive, I sincerely don’t understand the apparent outrage in many of these watches. I’ve never owned a GM product, and in fact have managed to spend my entire life owning but two marques, one “foreign” and the other “domestic.” I’m not a fanboy of anything other than machines.
Therefore, please excuse my temerity when I say I don’t find .29 to be particularly impressive for a passenger car of the Volt’s proportions. I also don’t find it “seriously bad.”
El Norte: Actually, it probably had a Cd of .0. There was no 1985 300E. Introduced as an ‘86…
My 300E was a 1986 model, but the W124 was put in production in Europe in 1984 as a 1985 model. In any case, it DID have a Cd of .28.
I have to wonder if GM has decided to settle for some arbitrary definition of “good enough” on the Volt’s aerodynamics. I can see three main possible reasons:
1) The intense pressure to get it ready for something resembling production has cut way down on the time available for wind tunnel testing and the kind of air management that’s necessary for a good Cd.
2) The intense pressure to keep the cost from spiraling even more out of control has cut the funds available for special (i.e., not parts-bin) mirrors, underbody air channels, and the like.
3) Both of the above.
It’s the kind of thing that leaves one wondering, “Jesus, what OTHER corners are they cutting?”
I suppose my main points are:
1) the Volt is not going to be as great as GM is making it seem.
If GM survives I think it will be. If GM does not survive then the pure electric or almost pure electric hybrid cars coming from Nissan/Renault, Chery, and others will be.
2) More taxes? Really? I think the government could save money elsewhere (cough, stupid war).
The money being spent on the stupid war is coming out of our education, social security, FDA inspections, OSHA, FAA, and other budgets.
3) Do not listen to the GM management. The Bob Lutz Award was created for a reason.
I think it is a good idea to listen to all sides. Not listening to all sides got us into the stupid war.
I’ve mentioned this before:
My ten year old civic HX gets 40 mpg hwy (it used to get ~43, and then I started driving like an asshole). Sure, it has no modern safety features, but the previous gen civic HX has excellent crash test ratings and supposedly gets 40+ hwy. We do not need $40,000 niche vehicles that have $20,000 of whiz-bang technology to manage 50 mpg. We need vehicles that are simple, efficient, and reasonably affordable. Spend a bit more of R&D funds to reduce weight and tweak aerodynamics, optimize the final drive ratio for mpg’s (damn you, Honda Fit), and call it a day.
I also have been buying reasonable cars for years but we should never call it a day. Maybe we can find a way (or several ways) to stop shipping large amounts of our money to people who hate us.
If we had had a $0.50 to $1.00 additional tax on gasoline for the last decade (still far below the taxes Europeans pay) we might have saved the US auto industry from their own stupidity and had money for more and better maintained roads and/or saved enough fuel so that we didn’t start a war to steal Iraq’s oil.
CD is not the complete equation for aerodynamics,
FRONTAL AREA!!!!!!!!!!
CD is calculated regardless of size.
a 747 has a CD of .11
an Indy car has a CD of .75!! (downforce to stay from flying off the road)
The difference is the frontal area
Look at that mileage VW super high mileage car, its frontal area is half as normal.
folkdancer:
I believe we have the same position on the war – I was saying that it is a waste of resources and that instead of increasing taxes, the money that is being used in Iraq should/could be used for supporting mass transport/road maintenance (among other things – as you noted above).
I agree that we should never stop developments in the auto industry. I would love to see electric cars. However, from an environmnetal perspective (not to mention a financial perspective), I question the current hybrids. For example, if people really want to use less resources, they should be purchasing Yarii instead of Prii. The cost difference between the vehicles represents the additional materials in the larger prius, the batteries, electric motor, etc. Yes, this may yield an extra 10-15 mpg, but does this offset, the additional resources expended during the design, manufacturing, and end of life processes of the Prius. I, for one, am not yet convinced. I know this comparison is somewhat unfair because of the larger interior volume of the Prius, but the Yaris would serve the needs of 90% of Prius users.
I would love to see a comparison between a standard prius and a prius sans the hybrid drive. On the hwy, theoretically, the mileage should improve. And the environmentally quesitonable battery (IMO) would be avoided.
Speaking of batteries, a while back I tried to find out information about battery manufacturing and recycling. Specifically, I was looking for a detailed technical paper outlining the life cycle analysis (LCA) of batteries (various types). My searches have turned up non-technical BS. Does anybody here know of any sources that clearly describe LCA’s of batteries?
If we had had a $0.50 to $1.00 additional tax on gasoline for the last decade (still far below the taxes Europeans pay) we might have saved the US auto industry from their own stupidity and had money for more and better maintained roads and/or saved enough fuel so that we didn’t start a war to steal Iraq’s oil.
Again, I’m going to have to disagree with any increase of taxes. We need more efficient use of our current tax money (as in, not starting unjustified wars) before tax increases. Also, the generally poor position of the US auto industry is, as you pointed out, due to “their own stupidity.” Why should I have to pay taxes to artificially shift market preferences, and in turn prevent the US auto “leaders” from making poor business decisions? As you can tell, I’m against any kind of bailout …
If a fuel tax of $1.00 were added to fuel over the past decade, people still would have purchased thirsty vehicles.
For what it’s worth, I think that we agree on the basics, and disagree on the details.
Paul Niedermeyer :
August 20th, 2008 at 11:44 pm
“Actually, it probably had a Cd of .0. There was no 1985 300E. Introduced as an ‘86…
My 300E was a 1986 model, but the W124 was put in production in Europe in 1984 as a 1985 model. In any case, it DID have a Cd of .28.”
Cite, please?
folkdancer : The money being spent on the stupid war is coming out of our education, social security, FDA inspections, OSHA, FAA, and other budgets.
This statement is misleading. Debt is being generated to keep spending at typical growth levels.
Morea;
I took it that folkdancer was sarcastically pointing out that the money spent on the war was not being removed from infrastructure expenses for which that the federal government has no authority but is being withheld from a plurality of other uses for which the federal government has no authority.
I’m not one to argue that war spending is worthwhile but at least it’s something the feds have the authority and responsibility to do. The rest of the crap (cited above) they’re wasting my money on they have no business messing around with and any “savings” you’d like to generate should come from extra-constitutional activities.
cdotson, I get your point. I only wanted to clarify that budgets in these other areas are not going down.
don’t forget the Honda Civic at a .27