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Discussion Starter #1
I was genuinely surprised to hear of sub 7 second 0-60 acceleration times at the Bolt EV announcement at CES. I fully expected the Bolt EV motor to be nearly the same as the one in the Spark EV. The 2015 Spark EV motor puts out 140 hp / 327 lb-ft propelling that 2866 lb vehicle to 60 in about 7.2 sec. Assuming the Bolt EV weights 3500 lb, I expected the same motor would propel it to 60 mph in 8.4 sec, which happens to be about the same as the Volt. That's not quick, by any standard, but fast enough for the average driver.

Accelerating a 3500 lb Bolt EV to 60 in less than 7 seconds requires about 30% more horsepower than the Spark EV motor provides. I'm guessing the motor specs will be 180 hp (134 kW) and 325 lb-ft.

For reference, the RWD Model S 70, weights 4650 lb and uses a 315 hp / 325 lb-ft motor to hit 60 in 5.5 seconds.
 

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Looks like it'll be 200 hp / 266 lb-ft. I'm guessing they traded some torque for horsepower because a 200 hp car makes for better marketing. It might also help with the acceleration times at highway speeds.
 

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Looks like it'll be 200 hp / 266 lb-ft. I'm guessing they traded some torque for horsepower because a 200 hp car makes for better marketing. It might also help with the acceleration times at highway speeds.
Is there a link/source? I think you're right on the marketing angle -- horsepower ratings sell cars.

Regarding the motors, given that some time has passed since the Spark EV was engineered, it makes sense that GM would incorporate improvements into its new flagship EV.

Btw I'm envious of your Spark EV, at least for now. :D I couldn't lease one here in Arizona. A friend of mine in California has one, and he let me drive it. I was impressed with the acceleration and smooth ramp-up! If I could have, I would have leased one in a heartbeat. The presumably wider-availability of the Bolt EV is one of the reasons why I am so strongly interested.

Edit: just clicked the Wheelwell link in your signature. Totally envious of your E30 M3, not fair :D. Between the Bolt and the M3, you'll have the best of both ICE and EV in my opinion.
 

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Discussion Starter #4

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GM released this press release today:

Drive Unit and Battery at the Heart of Chevrolet Bolt EV
Engineers focus on careful balance of range and performance

DETROIT, Mich. – The 2017 Chevrolet Bolt EV does more than set a new benchmark for affordable, long-range EV driving. It also raises the bar when it comes to driving performance.

Engineers developed the Bolt EV's propulsion system to offer more than an estimated 200 miles (based on GM estimates) and a delightful driving experience that's more akin to a compact sports sedan than a small utilitarian crossover.

"Being the leader in range and affordability means nothing if the car isn't going to excite you each time you get behind the wheel," said Josh Tavel, Chevrolet Bolt EV chief engineer. "That's why the team was tasked with delivering a propulsion system that would also make the Bolt EV an electric vehicle that owners would love to drive."

Single Motor Drive Unit

Like most EVs on the road, the Bolt EV's drive system uses a single high capacity electric motor to propel the car. But it's the smooth, powerful and quiet motor design, gear configuration and shift-by-wire system that separates it from the pack.

The engineering team designed the Bolt EV's electric motor with an offset gear and shaft configuration tailored to meet efficiency and performance targets – most notably more than an estimated 200 miles of range. The motor is capable of producing up to 266 lb.-ft. (360 Nm) of torque and 200 hp (150 kW) of motoring power. Combined with a 7.05:1 final drive ratio, it helps propel the Bolt EV from 0-60 mph in less than seven seconds.

Power delivery is controlled by Chevrolet's first Electronic Precision Shift system. This shift and park-by-wire system sends electronic signals to the Bolt EV's drive unit to manage precise feel and delivery of power and torque, based on drive mode selection and accelerator inputs. A by-wire shifter requires less packaging space than a traditional mechanical shifter, resulting in more interior space and improved interior layout.

60 kWh Battery System
Having more than 1.3 billion miles of EV experience from the Chevrolet Volt helped Bolt EV battery engineers and strategic partner LG Electronics to develop an all-new cell and battery pack to offer more than an estimated 200 miles of range.

Battery system preliminary specifications include:
60 kWh lithium-ion battery pack.
288 lithium ion cells
Five sections
10 modules
96 cell groups – three cells per group
960 lbs. (435 kg) total weight

"You usually have a battery cell that delivers either the desired levels of energy or power, but not traditionally both. With this cell design and chemistry we were able to deliver a battery system with 160 kilowatts of peak power and 60 kilowatts hours of energy," said Gregory Smith, Bolt EV battery pack engineering group manager.

The battery uses active thermal conditioning, similar to the Chevrolet Volt, to keep the battery operating at its optimum temperature, which results in solid battery life performance. The Bolt EV battery will be covered by an 8-year/ 100,000 mile (whichever comes first) limited warranty.

Inside the battery pack – which spans the entire floor, from the front foot well to back of the rear seat – is a new cell design and chemistry. The nickel-rich lithium-ion chemistry provides improved thermal operating performance over other chemistries, which requiring a smaller active cooling system for more efficient packaging. The chemistry allows the Bolt EV to maintain peak performance in varying climates and driver demands.

The cells are arranged in a "landscape" format and each measures in at only 3.9 ins. (100 mms) high and 13.1 ins. (338 mms) wide providing improved packaging underfloor. The lower profile cell design enabled the vehicle structure team to maximize interior space.

The battery system is mated to a standard equipment 7.2 kW onboard charger for regular overnight charging from a 240-V wall box. A typical commute of 50 miles can be recharged in less than two hours. Bolt EV also features an optional DC Fast Charging system using the industry standard SAE Combo connector. Using DC Fast Charging, the Bolt EV battery can be charged up to 90 miles of range in 30 minutes. Outside temperatures may affect charging times.

Regen System Provides One-Pedal Driving

Regenerative braking has become more than just a tool to boost range, it's also transformed into a feature that can provide an improved EV driving experience. The Bolt EV features a new regenerative braking system that has the ability to provide one pedal driving.

"Interviews with EV enthusiasts indicated their desire for one pedal driving capability on the Bolt EV. One pedal operation boosts the thrill and uniqueness of EV driving," Tavel said.

Through a combination of increased regenerative deceleration and software controls, one pedal driving enables the vehicle to slow down and come to a complete stop without using the brake pedal in certain driving conditions.

When operating the Bolt EV in "Low" mode, or by holding the Regen on Demand paddle located on the back of the steering wheel, the driver can bring the vehicle to a complete stop under most circumstances by simply lifting their foot off the accelerator, although the system does not relieve the need to use the brake pedal altogether.

Operating the Bolt EV in "Drive" mode and not pulling the paddle while decelerating delivers a driving experience where usage of the brake pedal is required to stop.

Founded in 1911 in Detroit, Chevrolet is now one of the world's largest car brands, doing business in more than 115 countries and selling around 4.8 million cars and trucks a year. Chevrolet provides customers with fuel-efficient vehicles that feature engaging performance, design that makes the heart beat, passive & active safety features and easy-to-use technology, all at a value. More information on Chevrolet models can be found at www.chevrolet.com.
 

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Discussion Starter #8
Let me amend my last comment about the E30 M3. I'd love to have the powertrain in a modern version of the E30 M3. Something like the current M2 but cheaper and with an electric powertrain. The Tesla Model 3 *may* be that car.
 

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Let me amend my last comment about the E30 M3. I'd love to have the powertrain in a modern version of the E30 M3. Something like the current M2 but cheaper and with an electric powertrain. The Tesla Model 3 *may* be that car.
That's kind of what the ActiveE was. But they're extremely rare, and I think they were lease-only, so good luck finding one used.

https://en.wikipedia.org/wiki/BMW_ActiveE
 

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It's unclear what they mean by 200 HP.

Generally electric motors can tolerate extreme overloads for limited intervals with no damage. Some motors have a rated duty cycle. For example, my elevator motor is rated at 2 HP with a 30% duty cycle. I'm quite certain that the Bolt motor could not produce 200 HP continuously. With a top speed limited to 92 mph, it would be impossible to force the motor to deliver 200 HP for more than a few seconds anyway unless one were speeding up a very steep hill with the car heavily loaded and a head wind. It may be that the continuous duty rating of the motor would be only 50 HP or so which is fine.
 
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