Chevrolet’s Volt and Fisker’s Karma couldn’t be any more different yet alike at the same time. The Volt is techy, but otherwise a sensible compact family car. The Karma is a high-line chariot for those wanting something much splashier than a Volt.
On any other day they’d have little reason to be compared except for one thing. For now, they’re America’s only extended-range electric vehicles capable of driving 25-50 miles solely on electric power but with gasoline backup when needed. This is within limits of what studies say a majority of Americans travel each day. Thus, if kept within their recommended daily allowance of prescribed electric range, the Karma and Volt can blissfully bypass gasoline stations for months on end. This means they could cost far less to operate than regular hybrids let alone ordinary cars, all the while saving petroleum and emitting next to nothing.
We’re highlighting these attributes front and center as they’ve been known to be under-emphasized by some assessing these cars according to different priorities. While everyone is entitled to determine what’s important to them, it is these cars’ EV capability with “no range anxiety” that enables proponents to look past other critiques including their relatively high prices, and just-OK gas-only mileage.
About Those Plug-in Powertrains
The rear-wheel-drive Karma is the only pure series hybrid passenger car available. Unlike a parallel hybrid – such as a Toyota Prius which uses its engine to mechanically drive the wheels along with its electric motors – the Karma’s engine never mechanically drives its wheels. Its GM direct-injected 2.0-liter four-cylinder turbocharged engine instead energizes matched twin electric motors offering combined output of 403 horsepower and 959 pound-feet of torque. This power is channeled via a single-speed transmission and the gas engine can augment the electric supply in Sport mode, or the car can run in battery only Stealth mode assuming its 20.1-kwh A123 Systems lithium-ion pack has more than 15-percent charge remaining.
The front-wheel-drive Volt uses a naturally aspirated 1.4-liter four cylinder feeding a 16.5-kwh LG Chem li-ion battery to send current to its two differently sized electric traction motors. It is a series hybrid most of the time, but its planetary gearset transmission under certain conditions does mechanically assist the front wheels. GM decided to occasionally use the engine in parallel hybrid mode because it proved more efficient under certain conditions. Unlike the Karma, the Volt’s engine cannot be used to augment electrical current to its traction motors beyond standard EV power settings.
In attempting to live up to its extroverted exterior, the Fisker is faster, but it’s no pavement shredder. Its 0-60 mph time of 7.9 seconds in Stealth mode, and 5.9 seconds and high-14-second quarter mile in Sport doesn’t crush many lower priced sporty cars let alone the elites for which it presents a green alternative. It does outpace the Volt though which can run to 60 in around 8 seconds.
The Volt’s top speed is governed to 100 mph. The Karma is limited to 95 mph in Stealth mode, and 125 mph in Sport.
Both cars are portly, having dual drivetrains and dual energy storage merged into one. Both place their batteries in a center tunnel inboard from crash zones. This mass centralization self-compensates to a degree by augmenting handling along with suspension calibrations that help conceal the Volt’s nearly 3,800 pounds, and the Karma’s over 5,300 pounds.
Suspension and Brakes
Managing the Karma’s extremely rigid alloy frame are front and rear control arms designed and calibrated with input from engineers that set up the Ford GT.
Set stiffer and using sticky Goodyear F1 sport tires, the Karma’s lateral acceleration figures average 0.92g. The Volt, ever the more sensible, is set softer, equipped with less-grippy, but more fuel-saving low rolling resistance Goodyear Assurance tires, and averages 0.78g on a skidpad.
Both use ABS-equipped regenerative braking. The Karma’s Brembo monobloc calipers – six piston in front, four in rear gripping 14-plus inch rotors – are world class overachievers and the Volt’s brakes work well also, stopping on good pavement from 60 mph in under 120 feet, compared to the Karma’s 110.
Up front, both cars offer enough legroom, headroom and adjustability for most full-size Americans. The Volt saves weight with manually adjustable seats, and the deluxe Karma adds to its body mass index with electrically adjusted seats.
Fisker says it copied a military powertrain design, but where it mirrors the Volt further is its battery tunnel separating front and rear occupants also eliminates the middle rear seat. What’s more, both cars only provide so-so rear seat space.
The Karma’s rear legroom is a bit shorter, and both cars can trap larger feet attempting to squeeze under the front seats. This is not unusual for cars of the semi-practical crowd to which the Karma belongs. It may be less excusable for the Volt which cannot plea the usual alibis only supermodels get away with, and compared to the Prius it was supposed to beat, it comes up short in this area.
The Volt offers more storage space than the Karma being actually a hatchback disguised as a sedan. Its 10.2 cubic foot rear cargo capacity exceeds the Karma’s 6.9-cubic foot trunk and lack of fold-down rear seats.
Controls and Interface
These cars are represented as the new vanguard of an electric future. Alternately, one could contend they are only now catching up with art as old as members of the AARP. Their gee-whiz factor mimics imagery prophesied by movies, stories, cartoons and pictures since before the 1950s. With technology now able to bring fantasy to reality, their design and operational controls are a step closer to satisfying expectations that long lay dormant within society’s collective unconscious.
To wit, from the Volt driver’s seat you’re faced with connectivity plus a plethora of buttons, and two digital LCD screens – one in the instrument location, the other on the center stack. Look up and there are more buttons for OnStar and more in the ceiling. The gizmos are all pretty user friendly too. There is learning curve dependent on how technically literate you are, but it’s reasonably intuitive.
The Volt is a humble family car but the family can feel more like the Jetsons family in a cooler ride than the Volt’s platform-sharing cousin, the Cruze.
Now contrast that to the “timeless” design in the concept car turned production reality, the Karma. Far fewer buttons are visible for its personal command center, and what’s more, all interior materials are decidedly upscale. Where are the swaths of decent-grade plastic, rubberized materials and serviceable cloth as found in the Volt?
Plastic, smashtik. Our Karma was the mid-level EcoSport – not the base-level EcoStandard or environmentally super-sensitive top-shelf EcoChic which opts for only tasteful synthetic and recycled materials.
Nope ours had sacrificed cows for leather, but it at least is tanned with a 100-percent environmentally friendly process. It covers the dash top, seats in an asymmetric mix of leather and suede, and parts of the battery tunnel where you rest your elbow. Beyond that is recycled hardwood, alcantara, metal and acrylic.
As for the Karma’s unapparent controls for HVAC, entertainment, navigation, backup camera and more, this simplicity is in keeping with the discrete theme. They’re actually all integrated into a single 10.2-inch haptic feedback touch screen in the center stack.
Both cars provide satisfying experiences albeit of two very different flavors. Of the two, the Volt is probably more suitable to take the dog to the vet, or bring home the medium-large haul from the store.
Its is designed to satisfy mainstream America and grandmom may ingress and egress somewhat more easily than she would for the low and long Karma.
Both cars get started with a pushbutton. Both deactivate their electric parking brake with a similarly designed pull switch. The Volt uses a traditional gear selector whereas the Karma has an avante garde backlit, pyramid-shaped pushbutton gear selector.
Keeping to the futuristic theme, from 0 to 25 mph the Karma emits a pedestrian warning sound that is reminiscent of an extraterrestrial’s landing vessel that came to earth and sprouted wheels. It’s actually kind of cool, and fits with the Karma’s stage presence.
The Volt also warns pedestrians when needed by commandeering the horn, emitting a friendly chirp, not an impolite “get out of my way” tone.
Outward visibility is somewhat better in the Volt with exception of the A-pillars which impede view a bit more than the Karma’s. The Karma is easy enough to see out of, but does have that long hood up front with “muscular” fenders concealing its 22-inch wheels.
Punch the accelerator in all-electric mode, and the Karma is quicker but not amazingly so. With torque available off the line, both hit 30-45 mph quickly, and highway speeds acceptably also. Above 70, the rate of acceleration drops off.
Physics 101: Wind resistance increases exponentially at speed meaning the faster you rip toward “the ton,” the more drag must be overcome by the limited energy supply. This saps efficiency and while both cars have slippery aerodynamics, they’re set to perform best at ordinary speeds.
Contrast that to Tesla’s 85-kwh Model S which out drag races a 560-horsepower BMW M5 to 100. Do that a lot, and we suspect it won’t get near the EPA’s efficiency numbers.
As for steering the Volt and Karma, feel is much different also. In the Karma you know you are in a big machine and its fat tires – 255/35WR-22 front; 285/35WR-22 rear – need plenty of help from the electro-hydraulically assisted steering at parking lot speeds. At a walking pace, the Volt is nimbler with a tighter turning radius. Once rolling, either car goes where it’s pointed with minimal fuss and their weight helps each provide a comparatively complaint ride.
As the road gets twisty the Karma is arguably more rewarding. Even though it weighs as much as the Volt plus four 375-pound occupants, its chassis, suspension and tires make up the difference. But the Volt is agile too and would be even more so if its suspension were stiffer with perhaps beefier anti-roll bars or spring rates and given stickier tires too.
But the Volt is not pretending to be a sports car and balances suspension settings toward comfort which means more body roll. It is sporty though, and 85th percentile cornering antics at extra-legal, but not insane speeds are rewarded by crisp handling.
The Karma is set up like a grand touring car, and its grippy rubber slightly compromises mpg and all-electric range in favor of maximizing traction offered by its flat-cornering suspension.
One does wonder what would happen if the big car let loose if pitched too hard into a corner. All that mass sliding sideways might not be pretty. But it’s not really concerning, and it actually encourages you to push the corners. In sharp, slow bends, mashing the accelerator can induce rear sliding oversteer for some tire- and mpg-ruining fun.
As U.S. Environmental Protection Agency (EPA) numbers already reveal, the Volt blows the Karma away. To a point. The lighter weight Volt relies on a 16.5-kwh battery, and uses only 65 percent of its capacity until the battery management system switches to charge-sustaining gas mode. The Karma uses 85-percent capacity from its 20.1-kwh battery. Thus their all-electric range (AER) is within a stone’s throw of each other.
Drive it sedately, and the Karma can do the whole 38 miles the EPA says the Volt’s battery provides. Actually the Karma is EPA-rated for 33 miles, and we’ve seen that and more. Both cars can hit 50 miles AER, but the Volt requires less nursing.
With finite battery reserves, you are encouraged to drive these cars “responsibly” (read: not like sports cars). If you do drive them hard with jackrabbit starts, speeding on the highway and anywhere else, expect AER to suffer.
This said, the EPA rates the Volt as 76-percent more efficient. That is, it’s MPGe (miles per gallon equivalent – see sidebar) is 98, whereas the Karma’s is 54. This means Karma electric costs are higher assuming the EPA cycle is correct. The German TÜV’s more lenient test says the Karma is good for 112 MPGe. You can take this for what it’s worth but it at least suggests easy going will mean better efficiency than the EPA estimates.
In gas-only mode the Volt again outscores the Karma with an EPA-rated 37 mpg vs. 20. Twenty is about what a comparably heavy Cadillac Escalade Hybrid musters but it cannot touch the Karma’s electric-only capabilities.
Again, efficiency numbers are dependent on how you drive. If you keep a cool hand, you can exceed estimates. Drive aggressively and you might think this energy saving talk is mixed with green wash.
What is the Right Choice?
Four possible answers: 1) The Volt. 2) The Karma. 3) Both. 4) Neither.
Of the two, the Volt obviously costs less, is cheaper to operate, thus promises a better return on investment.
The Karma – compared to an exotic V8 or V12 powered luxury car – is also inexpensive to purchase and operate. It’s half the price of an Aston Martin Rapide, for example.
But without a doubt the Volt has had far fewer quality issues – as in almost none. Actually, it has topped Consumer Reports’ owner satisfaction survey the last two years since its launch, displacing the Porsche 911 from that spot in the process.
The Karma has been recalled a couple times and has had reports of poorly fitted body panels, interior work, and electronic controls. However, its Finnish boutique maker Valmet also produces Porsches and Mercedes among other first-class cars, so we suspect it can get the quality control in line, and may have already.
Aside from this, both cars have been politicized, represent new technology, and there are plenty of fence sitters and detractors bandying various viewpoints.
Our take? If the cars really are viable – and many say they are – the market will vote its pocketbook, and veto unwarranted critical observations, real and imagined. Equally true is neither is perfect, both are first-generation examples and due to be followed by improved versions – but then that is always true of technology and both have their fans who say jump in, the water is fine.
The bottom line? The Volt and Karma are not right for everyone, but are meeting needs now. So, the only right answer is the one you decide.
What is MPGe in layman’s terms?
Simply put, it is how to compare the efficiency of electric vehicles. The Volt has a MPGe of 98, and the Karma gets 54 MPGe. So the Volt is 1.76 times more efficient, or the Karma will go 54 miles on the same electricity the Volt goes 98 miles. Efficiency is nice to know, but what about cost?
Without a little more information this MPGe number doesn’t give us what we can quickly equate when we see the MPG of a typical car; cost of the “fuel” we will be using. This MPGe number is based on 33.7 kilowatt-hours of energy usage. Why? Because the EPA has determined the energy in one gallon of gas is “equivalent” (the e in MPGe) to 33.7 kWh of electricity. So if we know what 33.7 kilowatt-hours of electricity costs, we could calculate the electric vehicle “fuel” cost.
If you know the cost of a kilowatt-hour at your home, the above information is enough to compare the fuel cost between a gas versus an electric vehicle, but for most consumers, the information in the tables below will paint a clear enough picture:
This entry was posted on Friday, January 4th, 2013 at 5:55 am and is filed under General. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.