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2015 BMW i8 review: BMW i8: The hyper hybrid

Capable of full electric drive, the BMW i8's concept car looks and carbon fiber body hide a ferocious Sport mode.

Wayne Cunningham Managing Editor / Roadshow
Wayne Cunningham reviews cars and writes about automotive technology for CNET's Roadshow. Prior to the automotive beat, he covered spyware, Web building technologies, and computer hardware. He began covering technology and the Web in 1994 as an editor of The Net magazine.
Wayne Cunningham
9 min read

When I first rolled out in the 2015 BMW i8, I didn't see the point. I drove this low-slung concept-looking plug-in hybrid under electric power until its limited battery range ran out, then watched as the fuel economy dipped well below 30 mpg in hybrid mode. But when I put it in Sport mode the truth dawned. The engine roared and blipped when I shifted gears and it handled the corners better than any BMW I had driven before.


2015 BMW i8

The Good

Concept-car looks help the 2015 BMW i8 stand out in the crowd and a carbon fiber body keeps weight down. The plug-in hybrid drivetrain allows 22 miles of electric range and total output reaches 357 horsepower.

The Bad

Skinny tires lack strong cornering grip and the hybrid drivetrain programming seems in need of refinement.

The Bottom Line

The 2015 i8 commands a very high price, but it is the most exotic car currently bearing the BMW badge and offers a dual personality between efficient electric and powerful sport driving.

The i8 is a sort of hyper-hybrid, what might have happened if Ferrari had developed the Prius. It exhibits two very distinct personalities: energy-obsessed engineer and troubled youth. Driving it in its Comfort and Eco Pro modes, I could have parked and forgotten all about it, but after moving the shifter to Sport mode nothing short of violence was going to get me out of the i8.

Hitting production in conjunction with the more affordable and mundane i3, the i8 represents BMW's radical rethinking of personal transportation in light of climate change issues and shrinking fossil fuel supplies. The i8 seems like a first effort by BMW to bring in new century efficiency yet maintain its performance legacy, and it will cost you dearly.

Base price in the US comes to $135,700 before adding any of the available "World" trim levels. UK buyers are looking at £99,845, although the i8's electric-only mode should avoid congestion charges and preserve the village green. Below the equator, Australians are looking at $299,000 for the i8, but just think how many more mutants Mad Max could evade on a precious gallon of gasoline.

BMW i8 looks like the future of driving (pictures)

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The i8 is certainly an extraordinary-looking vehicle, as if BMW built a concept car then forgot to get rid of all the interesting bits before putting it into production. While driving it, I got more attention than I had in even the bright orange McLaren 650S Spider .

Power front and back

Beyond its concept-car looks, the i8 uses a completely unique drivetrain, bearing no resemblance to even BMW's own hybrid vehicles. Tucked away somewhere in the car is a turbocharged 1.5-liter three-cylinder engine using BMW's valve timing and throttle control technologies to produce 228 horsepower and 236 pound-feet of torque, driving the rear wheels through a six-speed automatic transmission. That engine, a variant of that found in the 2015 Mini Cooper , gets a little help from the 11-horsepower starter motor, smoothing over turbo lag.

Driving the front wheels, the i8 uses a 129-horsepower electric motor, powerful enough to move the car all by itself when the 5 kilowatt-hour battery pack has enough charge. Oddly, a two-speed transmission sits between that motor and the front wheels. Filling the battery pack takes just 1.5 hours from a 240-volt source, and gives the i8 22 miles of zero-emission range.

2015 BMW i8
The i8 is like nothing else in BMW's line-up, and combines sport driving with efficiency. Josh Miller/CNET

BMW sets the total power output for the i8 at 357 horsepower and 420 pound-feet of torque, with a 0 to 60 mph time of 4.2 seconds. EPA figures show 76 miles per gallon equivalent, 28 mpg average on the gasoline engine alone. However, as is typical with plug-in hybrids, mileage will vary drastically depending on how frequently the car gets charged up.

Further setting it apart from the BMW line-up, the i8 makes use of carbon fiber for its passenger compartment and aluminum sub-assemblies for engine support and chassis. Unfinished carbon fiber was in evidence when I lifted the upward-opening doors, a subtle means of calling out the i8's use of this exotic material. That construction helps keep the weight down, but the i8 still tips the scales at a 3,455-pound curb weight.

I wanted to get a look at the engine, but the manual deterred me with a note that the hood could only be opened by BMW service personnel. However, a couple of simple latches in the cargo area let me gaze at the black metal box containing the battery pack, occupying a mid-body position in the car. A hatch on the left front fender covers a J1772 electric vehicle charging port, while a standard fuel filler sits at the right rear.

After limbering up with a few stretches, I worked my way under the door and into the driver seat. The i8 uses 2+2 seating, meaning there are padded spaces behind the rear seat where I could put my computer bag or possibly some groceries. A compartment under the rear hatch could have held a couple more grocery size bags.

2015 BMW i8
Upward opening doors and a low-slung body make getting in the driver's seat a challenge. Josh Miller/CNET

Eco Pro, Comfort and Sport

Appropriately for a car from the future, the i8 lit up accent lighting and various screens around the cockpit when I pushed the start button, but no burst of combustion broke the quiet. In Comfort mode by default, the LCD instrument panel tinted its speedometer and power gauge blue. BMW's usual rocker switch for drive modes, mounted on the console, only offered Comfort and Eco Pro modes, lacking the Sport and Sport Plus settings of other BMW models. A button labeled eDrive on the console promised to keep the i8 driving under electric power, if the battery would allow it, while the shifter had a pull-to-the-left Sport position.

With 9 miles of electric range remaining, I piloted the i8's attention-getting body into a typical city traffic slog. The car felt comfortable and light, easy to maneuver and putting me in a lower position versus traffic than even in my own Z3 Coupe. The i8 accelerated smoothly, obviously metering out the electric motor's 184 pound-feet of torque to prevent jerkiness. And where I was used to seeing other electric cars drop apparent range much more quickly than the distance I covered, the i8's range display appeared true to its word, matching mile for real mile.

2015 BMW i8
Unlike most of its models, the i8 only has Comfort and Eco Pro modes on the console-mounted rocker switch. Josh Miller/CNET

Coming to one of San Francisco's notorious hills, I heard the i8's engine kick in, seamlessly intervening to keep strain off the battery. BMW uses the navigation system to look at the road ahead, adjusting the drivetrain power output in advance of ascents.

After depleting the battery, the car switched to hybrid mode. At least I assume it did, as the engine remained very quiet under normal acceleration. In fact, the i8 really felt no different between electric drive and hybrid modes. Switching from Comfort to Eco Pro detuned the throttle a little bit and reduced power to climate control, a big energy saver when outside temperatures aren't too extreme. The electric power steering felt loose and easy, making driving this extraordinary-looking car an easy and uninteresting experience.

In electric mode, the trip meter showed 99.9 mpg, but as I drove in hybrid mode that figure dropped like a very heavy rock from a very short building. Within an hour of driving I was down to the mid-20s, making me seriously question the value of the i8.

Then I got to one of my favorite twisty test roads and, forgetting about fuel economy concerns, jammed the shifter over to Sport mode and experienced the revelation. The engine roared to life and I felt the i8's full power potential on tap from the accelerator. The car dove forward in complete justification of its exotic looks. Leaving the transmission to shift by itself or taking over with the steering wheel-mounted paddle shifters, I heard the delightful rev pops from the engine.

As good as the i8's engine noise sounded, BMW apparently pipes its normally muffled note into the cabin through the audio system. At least it's only amplified, and not completely faked.

2015 BMW i8
At 195/50 R20, the front tires are a bit skinny, and the rear tires are only 20 mm wider. Josh Miller/CNET

The roads were very wet, so I took the turns with care, especially as BMW chose relatively skinny tires (195/50 R20 on the front and 215/45 R20 at the rear) for the i8. However, the i8's rigid body and quick turn-in inspired confidence in the corners, and I was left with an impression similar to what I found the previous week with the McLaren 650S. And unlike that rear-wheel-drive racer, the i8 powers all four wheels. CNET editor Brian Cooley noted that the i8's front tires dug in on wet corners, helping the car maintain grip.

When you consider the two power sources driving different sets of wheels and the two intervening gearboxes, BMW did a masterful job of making the i8 an exceptional driver. The car must match power front and rear, then decide which end needs more torque based on road and driving conditions. The fact that it all works so well can be chalked up as a big win for BMW engineers, and I hope to see the company capitalize on this technical achievement in other cars.

More interesting, when I put the car back into Comfort mode, the electric range was miraculously back up to 8 miles. having stored the excess from my hard accelerating and braking. A stretch of easy driving on a long descent down from a mountain added a couple more miles. That extra juice in the battery let the hybrid system work more efficiently, as my fuel economy began to climb, letting me finally report an average of 31.8 mpg for my time with the car. That behavior suggests BMW may have a little more refinement to do on the i8's hybrid drive efficiency.

Carry-over tech

This example came with energy-saving LED headlights and a head-up display, projecting vehicle speed and route guidance on the windshield. A camera mounted at the top of the windshield enabled a pre-collision braking system, which also warned me if it thought I wasn't braking soon enough to avoid hitting cars ahead. BMW offers a surround-view camera for the i8 to help keep its carbon-fiber body panels unscathed.

2015 BMW i8
The i8 offers the same split-screen view as other BMW models, here showing navigation on the left and trip computer on the right. Josh Miller/CNET

As I've seen in other BMW models, the i8's cabin electronics are among the best available. Sitting up on the dashboard, BMW's standard wide LCD shows navigation, stereo and online information, along with a few added screens detailing the car's energy usage. BMW's latest iDrive controller, with its embedded touchpad, let me control all on-screen features. Likewise, voice command was present, giving me easy control over most infotainment system functions.

The excellent navigation system shows detailed maps with extensive traffic coverage, giving route guidance a better chance of keeping the i8 out of traffic jams. I marveled at how many surface streets in downtown San Francisco were covered by the live traffic information. Making use of the head-up display, the turn-by-turn directions are as clear as any I have seen. The navigation system's points-of-interest database added a section for charging stations, appropriate for the i8. But when I checked the list it was oddly empty, not showing any of the many charging stations I know exist around San Francisco.

BMW offers a very good set of connected features, including online destination search and third-party apps. Some of these connect through the car's built-in data connection, and some rely on the BMW ConnectedDrive app for smartphones. This app is fully functional for iPhone, but the recent Android version seems to lack many of its counterpart's features. I have been extremely impressed by BMW's online features in cars such as the M4 , but none were working in this i8. BMW assures me that all of its connected features come standard in the i8, which I would expect for such a high-priced and futuristic car. In addition, the i8 gets a telematics system letting owners check the charge status from a smartphone app.

The i8's own head unit showed me different charging options, such as the ability to take advantage of low-priced electricity in the earliest hours of the morning.

Audio sources ran the full gamut of what I've seen in other BMW models, from an onboard hard drive to HD radio. And similar to BMW's latest, I was able to use the i8's onscreen interface to select music from my Bluetooth-connected iPhone. That music library interface, identical to that used for devices plugged into the car's USB port and the onboard hard drive, still suffers from an over complicated design. It takes far too many button pushes to find and play music.

Music, and the engine note, plays through a Harman Kardon audio system built for the i8. Featuring 11 speakers and a 360 watt amp, I enjoyed listening to music in the car, although the quality never rose to truly sharp audiophile levels.

2015 BMW i8
LED headlights are an option for the i8, and help preserve its limited electric range. Josh Miller/CNET

Dual personality

The 2015 BMW i8 is an extraordinary technical achievement. Although pricey, it is near the cheapest car you can get with a full carbon fiber body. Its look is pure concept, and much more interesting than its sibling, the i3. Although I found some odd issues with its fuel economy, this plug-in hybrid system impressed me with its power control.

Most impressive was the i8's Sport mode, which made for a surprisingly different ride. I've noted and appreciated the dual nature of previous BMW models, especially those bearing the M, but the i8's personality split is so wide that it deserves two model names.

BMW hasn't played up its connected car features much, but they are impressive, as is its cabin tech. The i8 comes with the latest iDrive system, featuring excellently detailed maps and very functional voice command. The connected features, although not working on this example, make online destination search quick and easy. Integrated apps offer online music and safe social media status updates.

If the i8 represents BMW's future, the company is already years beyond the competition.

tech specs

Model 2015 BMW i8
Trim Giga World
Powertrain Hybrid gasoline-electric with turbocharged direct injection 1.5-liter three-cylinder engine and 129-horsepower electric motor, 5 kilowatt-hour lithium-ion battery pack, six-speed automatic transmission
EPA fuel economy 76 mpg equivalent/28 mpg gasoline only average
Observed fuel economy 31.8 mpg
Navigation Standard with live traffic
Bluetooth phone support Standard
Digital audio sources Internet-based streaming, Bluetooth streaming, onboard hard drive, iOS integration, USB drive, satellite radio, HD radio
Audio system Harman Kardon 360-watt 11-speaker system
Driver aids Head-up display, rear-view camera
Base price $135,700
Price as tested $138,650

2015 BMW i8

Score Breakdown

Performance 9Features 9Design 9Media 9


Body Type CoupesAvailable Engine HybridBody style Coupe