2008 Tesla Roadster
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VIEW OUR EXCLUSIVE MOTOR TREND VIDEO OF THE TESLA ROADSTER IN ACTION.
So how fast is the Tesla Roadster really? In a few seconds, we’re gonna find out because framed by its porthole-size windshield is a deliciously straight stretch of Skyline Boulevard, a knockout snake of a road we’ve never heard of before in the coastal hills above San Carlos, California. San Carlos, in case you’re not Google-Earthing at the moment, is the inviting, northwestern Silicon Valley ‘burb where Tesla decided to settle its unpretentious research and development quarters about four years ago. Through the trees, we occasionally glimpse Stanford’s 285-foot-tall Hoover Tower some seven and a half miles away.
Okay, then, I’ve got the brake pedal stapled to the floor. The mirrors are scoped for innocent traffic. Coast is clear. Dip into the accelerator and…remember that Mark Twain quip about the coldest winter he ever knew being a summer in San Francisco? Ditto that for this San Carlos place. Except it’s now December, the Roadster’s top is AWOL, and an Arctic front is leaning in from the gray Pacific. But back to business.
Can an electric sports car really deliver sports-car thrills? Absolutely-though its dynamics are velvety in their violence and its silence is almost snakelike.
I lean into the accelerator, brace myself and…er, hold on, we’ll get to that. I first want to tell you about the irony of this car’s name. Haven’t you wondered where “Tesla” comes from? Automotive historians might be acquainted with the story about Thomas Edison famously giving encouragement to a young employee named Henry Ford (“Young man, you have it. Keep at it. Electric cars must keep near to power stations”). However, the reality is that cantankerous Tom would soon embark on thousands of experiments aimed precisely at cracking the automotive battery nut, and in 1904 finally introduced-amid much stage-managed hoopla-his nickel-iron battery for electric cars.
It didn’t work out, at least not automotively. But the tie-in with the 2008 Tesla Roadster is that, a year before the Ford conversation, Edison had a giant row with another employee, a curious Serbian immigrant named Nikola Tesla. Depending on which story you like, Edison either did or didn’t renege on a $50,000 payment to Tesla. Edison’s version was that he meant it as a joke. Either way, the historic champions of direct current, Edison, and alternating current, Tesla’s baby, were pretty much at each others’ throats after that. So what gets me is that now, a century later, the first popular electric car to crack the battery nut is called a Tesla, not a Tom. Sure, Tesla was a genius. But did he even try to make car batteries? Nooo.
All right, then, back to the car-specifically, its batteries. The reason I’m braced for a wallop when I nail that accelerator isn’t the watermelon-size electric motor’s 248 horsepower. What’s worrying my neck is the combination of the motor’s 211 pound-feet of zero-rpm torque and the ease with which its 6831-cell, lithium-ion battery pack can juice the little banshee. Note that, at an estimated 2690-pound curb weight, the Tesla Roadster has a weight-to-torque ratio of 12.7 pounds/pound-foot. By comparison, it’s natural reference, the sizzling Lotus Exige S (with 165 pound-feet of torque and 630 fewer pounds) offers 12.5 pounds/pound-foot-but only when you finally reach 5500 rpm. Notably, that’s not zero rpm.
Although the battery pack contains the equivalent of just 2.1 gallons of gasoline (before recharging losses), Tesla claims the Roadster’s efficiency is six times that of rival sports cars, and it contributes ten-fold fewer CO2 emissions. Perhaps. What’s painfully apparent as you delve into the world of battery EVs, plug-in hybrids, and hydrogen fuel-cell vehicles is that everybody’s sequence of PowerPoint charts, funnily enough, favors themselves.
Still, the Tesla is undeniably, unbelievably efficient: Given its miniscule ration of “electric” fuel on board and its 220-mile, combined-cycle range (recently reduced due to a subcontractor’s miscalculation), the Roadster delivers roughly 105 miles per electric gallon. Assuming that electricity is (optimistically) sourced from a highly efficient combined-cycle, natural-gas-fired powerplant (which Tesla claims can provide an efficiency of 52.5 percent from well to outlet), the Roadster’s gasoline-equivalent well-to-wheel mileage works out to something like 55 mpg. That’s roughly 1.5 times (or higher, by Tesla’s calculations) that of the Prius, the green standard of current automobiles. By the way, there’s little cause to fret about laptop-scenario battery infernos, either-the battery is liquid-cooled by the same refrigerant used by the air-conditioner; all those cells are bathed in a total of 27 square meters of surface-area to squelch any troublemaking hot-spots.
Tesla’s real troublemaker hasn’t been batteries but its transmission. Or make that, transmissions. An electric car, even one with a 13,500-rpm redline needs at least two cogs to get lickety-split to 60 and still top-out at 125 mph. Transmission Design One proved unreliable; Transmission Two, which is fitted to the car I’m in, operates nicely but isn’t lasting more than a few thousand miles. Presently, two more subcontractors are simultaneously going full-bore on transmission designs Three and Four to accelerate the development. Confronted at a recent Tesla Town Hall Meeting attended by still enthusiastic, but detectably restless deposit-placers (there are some 600 of them at the moment), Chairman Elon Musk predicted production would start slowly but ought to reach full tilt by summer. When a questioner queried if Tesla’s investors were getting skittish, Musk (who sold PayPal for several hundred million dollars) replied, “Unequivocally, I will support the company to whatever extent is needed. I [Musk's bank account] have a long way to go before [money's] a problem.” Optimistically, Musk noted that their painful transmission development is preemptively smoothing the road for the next Tesla, the code-named “WhiteStar” sedan.
The current transmission is a two-speed, DSG-like double-clutch design, with the motor automatically spinning up or down to match revs. Move the lever and you’re actually just throwing a switch; there’s no clutch pedal and the sound is akin to an electronic yelp. Think of C3P0 being kicked.
Although it’s a prototype I’m driving, the differential is going to need a lot less lash when you snap on and off the accelerator, which presently elicits a nasty drivetrain buck (this probably isn’t helping the brittle transmission, either). “Drop-throttle” basically tailors the car’s inherent mild understeer, but what’s interesting is the regen’s strong drag when you lift. In fact, often the friction brakes aren’t really needed at all, and when they are, your right foot gets to enjoy old-fashioned sports-car braking feel because the regen isn’t concomitantly ramped up. On the move, the Tesla’s ride is surprisingly supple. Lotus has done a laudable job of stretching its Elise chassis two inches and accommodating a near-1000-pound battery (offset by a carbon-fiber body) while keeping this thing a frantic road dart on twisty roads.
I check the mirrors again. Still no traffic. I’m almost grimacing as I release the brake and pound the accelerator to the floor. Whrrrrrrr…30 mph, 40 mph, 50…in the four seconds it’s taken to read this sentence, the Roadster has shrieked to 60 mph (Tesla’s claimed 3.9 seconds would seem entirely plausible in a controlled setting). There’s no wheelspin, axle tramp, shutter, jutter, smoke whiff, cowl shake, nothing. I’m being eerily teleported down the barrel of a rail gun, head pulled back by a hard, steady acceleration. Bizarre. And before too long, profoundly humbling to just about any rumbling Ferrari or Porsche that makes the mistake of pulling up next to a silent, 105-mpg Tesla Roadster at a stoplight.
|2008 Tesla Roadster|
|Vehicle Layout||Mid-motor, RWD, 2-pass, 2-door roadster|
|Motor||AC synchronous, 248-hp/211-lb-ft|
|Curb Weight||2690 lb|
|Length x Width x Height||155.4 x 67.8 x 44.4 in|
|0-60 mph||4.0 sec|
|Fuel Economy||105 mpg gas equivalent|
|Range, Combined||220 miles|
|Recharge Time||3.5 hrs @ 220 volts/70 amps|
|On Sale In U.S.||Currently/delivery in 2008|
IS TESLA IN TROUBLE?
After our pleasant visit to Tesla’s San Carlos tech base, we began intercepting ominous signals about Tesla throughout the EV blogosphere. Most notable, Martin Eberhard (pictured), a Tesla founder, was forced out and has subsequently begun his own blog, www.TeslaFounders.com. In a recent entry — which has since been removed after pressure from Tesla — Eberhard enumerated the series of sometimes abrupt and random-appearing firings that have been taking place at his former company (among them, Wally Rippel, a genuine EV visionary).
Tesla fans have consequently been on red alert, some tea-leaf-readers going so far as to say the company is going under or preparing itself for sale. We, obviously, have no idea what all this means. But as students of the car business, none of us is raising eyebrows just yet. Startups are brutal. Few succeed. And it’s not unusual to see periodic chaos among those who do. Elon Musk, Tesla’s chairman, has stated that the company needs to trim its sails toward producing cars and fulfilling orders, and not everybody’s cut out for letting go of their baby, transmission reliable or not. A Tesla spokesman has also enumerated various personnel overlaps that needed inevitable paring. Let’s hope that’s all we’re seeing because the Roadster is a cool automobile technically, a cooler automobile to drive, and an historic game-changer in our perception of battery-electric vehicles.
Finally, after reading through the cottage industry of blogs orbiting Tesla Motors, I’m amused to discover that Elon Musk’s (wanted or unwanted) nickname is “Edison.” So maybe my tongue-in-cheek speculation that the car might be better named “Tom” wasn’t so far off! - Kim Reynolds, Technical Editor
AND THERE’S MORE…
Just as we posted our Tesla feature and video to the Web, more news regarding the company’s transmission conundrum appeared on Tesla Motors Web site. As speculated in our feature, there will in fact be an interim, one-speed transmission. The bad news is that its compromised ratio (needed to achieve a sports car-like top speed) will temper the car’s acceleration rate to 5.7 seconds to 60 mph, instead of the 4-flat (or less) that was originally promised (and recorded by us from a prototype two-speed transmission car).
The twist is that the “permanent transmission,” which will appear later this year as production really ramps up, will also be a one-speed. Huh? Does this mean Tesla is permanently lowering its performance targets?
No — due to an unexpected solution. Instead of achieving their original acceleration bogey via a two-speed tranny, they’re simply beefing up the motor’s power by enhancing the PEM (Power Electronics Module) and adding an advanced cooling system to the motor. Folks who are delivered early cars with the interim hardware will be called in (coincident with the production increase) for an update to the latest spec, free of charge. What isn’t clear is whether this hardware swapping will include a new, cooling-enhanced motor as well, or instead see a client’s existing motor somehow retrofitted.
What all this suggests is that the problems with the two-speed transmission must have been onerous indeed. This is a costly fix. Moreover, the motor is already at the technology’s power density fringe; getting more out of it can’t be easy. And, to be honest, I’m a little saddened to see the two-speed go as it was rather interesting to drive, though its relaxed shift time would probably be difficult to ever trim due to the giant ratio gap a two-speed necessitates. On the other hand, Tesla rightly points out that the car’s quarter-mile times will benefit with the elimination of the time-wasting gear shift at 65 mph. Furthermore, a one-speed works to an electric car’s inherent advantage in drivetrain simplicity.
Tesla says all regulatory approvals for sale are now in place, including EPA, DOT, and Federal Motor Vehicle Safety Standards. Moreover, Elon Musk, Tesla’s chairman, will be receiving the first production next week (time to park the McLaren, Elon), with series production starting March 17. - Kim Reynolds, Technical Editor
By Kim Reynolds