facts of drugs

BMW ActiveE Versus 135i

My daily car is a gas-burning BMW 135i. While I’m a big fan of the potential performance gains and obvious environmental benefits of electric cars, the market hasn’t yet met my needs. I’m not willing to sacrifice performance nor can I sacrifice range (the Bay Area is big — San Francisco to San Jose is 50 miles one-way). And otherwise superb Tesla triggers a different form of range anxiety — price range. The auto industry will solve these challenges in the next few years.

One of the more promising EVs on the horizon is the BMW i3, a car designed from scratch for an optimal electric experience and expected to go on sale in late 2013. As part of BMW’s test efforts, they have installed the i3′s electric powertrain in about a thousand BMW 1-series coupes, rebadged as the ActiveE. Today I drove one.

To be clear, comparing the performance of a 135i and the ActiveE is not a fair test, and I’m not going to declare a winner. The 135i weighs about 3,400 pounds and generates 300 horsepower from its twin-turbo 6-cylinder engine. The ActiveE weighs about 4,000 pounds and only generates 168 hp from its 32kWh batteries. But the ActiveE should provide a good feel for BMW’s electric powertrain, which will soon be found in the i3, as well as the impact on handling from switching a front-mounted engine for a rear-mounted electric motor and hundreds of pounds of batteries. If the ActiveE generally handles the way a BMW should, then the i3, which is expected to weigh well under 3,000 pounds, should be a blast to drive.

I drove the ActiveE from San Francisco to Stinson Beach, taking Panoramic Highway, one of my favorite coastal mountain roads in Marin County. In the city, pulling away from a stop sign is deeply satisfying with an immediate rush of torque and shift-free linear acceleration. The ActiveE doesn’t have a high enough power-to-weight ratio to be truly fast, but its smooth, instant acceleration at lower speeds makes it feel quick, especially when darting through city traffic. Crossing the Golden Gate Bridge and motoring up a steep hill on Highway 101 to 70 mph was uninspiring but again adequate. The motor is always ready to pull ahead with of course no downshift lag, but the absolute power of a downshift to 4th gear in the 135i is clearly absent.

The aggressive regenerative braking has a good linear feel, and I quickly stopped using my brake pedal for 90% or more of my braking. The ActiveE’s deceleration was about double the effect of coasting in the 135i at 4,000 RPM. Pretty aggressive and a good way to improve range. Reminds to look into whether electric cars light up their brake lights when aggressively decelerating without actual braking.

The tight curves through the forest and dropping into Stinson Beach were reassuredly pure BMW — well balanced, precise turning, and solid and progressive grip. Forced into using a 1-series shell designed for a gas engine, BMW carefully spread out the batteries in three locations: back of the engine bay, transmission tunnel, and trunk, maintaining a near 50:50 weight distribution. The center of gravity though could be improved, and will be in the i3 whose batteries will be located at floor level. If you try hard enough, you can slide the tail end accelerating out of a tight corner, but the ActiveE will mostly understeer significantly more than the 135i. The ActiveE has a high stack of batteries in the engine compartment (check out the bump in the hood) that I could feel, despite the car’s overall weight balance, pulling the front end out of my turning line.

All in all, BMW’s careful attention to weight distribution and refined electric powertrain produced a car that, while nearly 700 pounds heaver than a 135i, remained worthy of its blue and white badge. The i3 should be vastly better and is eagerly awaited.

  1. No comments yet.

  1. No trackbacks yet.