2004 Prius: Potential Green Meanie
Wednesday, May 25, 2011 at 06:54PM
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[A slightly abridged version of this article appeared in the February 2004 issue of Motor Trend Magazine] 

Photo enhancement: Misha Young

Practical, environmentally minded car buyers have a lot to like in Motor Trend's 2004 Car of the Year, the Toyota Prius: a roomy but compact five-door hatchback packed with high-tech goodies. Its sophisticated gas-electric hybrid powerplant qualifies it as a Super Ultra Low Emissions Vehicle. Aided by an aerodynamic shape with a standard-setting CD of 0.26, it delivers a combined EPA estimated city-highway fuel economy of 55 mpg. 

But what about its appeal to increasing number of car enthusiasts who expect their family-haulers to accelerate briskly, handle crisply, and deliver the substantial quotient of fun they’d find in a sport sedan?

Thanks to a weight below 3,000 pounds and more power than its predecessor had—from its gas engine, electric motor, and battery—it does get to 60 mph in about the same 10 seconds as a four-cylinder Camry. But I wonder: Could a tuner’s deft hands, fertile mind, and horsepower-driven desire turn this green machine into a meaner shade of green? Might the Prius spawn a new breed of tuners, the green meanies? I think it could.

Today, an enterprising owner could upgrade the Prius’s handling with some European-spec suspension parts and plus-one 16-inch wheels with grippier lower profile tires. I say “enterprising” because you can’t buy them through U.S. dealers. More aggressive suspension tweaks would drop it by an inch or so. 

The accompanying illustration shows more extreme modifications that would alter the car’s appearance more noticeably for the better. Slightly larger wheel openings would lower the car a bit more visually, while emphasizing even larger 18-inch wheels with correspondingly lower-profile tires. Removing the grille bar and enlarging the scoop below would increase airflow to the presumably warmer competition-tuned powerplant, while giving it a sportier look. Spoilers, wings, and other add-ons are unnecessary; the Euro-cool body-by-the-book aerodynamic shape already induces virtually no lift at either front or rear.

As discussed in our “Car of the Year” story last month, the stock propulsion system consists of a 76-horsepower, 1.5-liter engine and a 67-horsepower electric motor, coupled through a planetary gear set that constitutes an elegantly simple continuously variable transmission devoid of belts, pulleys, or clutches. The system takes advantage of the electric motor’s superior low-speed power for acceleration from a standstill (it develops maximum torque from zero to 1200 rpm) and the engine’s higher optimal speed for cruising (maximum torque comes at 4200rpm). Excess engine power spins a high-output generator that keeps the battery topped off. The motor draws on that stored energy when the engine needs help for passing or climbing, as a supercharger would.

Both halves of this impressive system offer tuning potential. Any supercharger made for Echo and Scion models, which shared the Prius block, might be adapted. A nitrous-oxide bottle could be installed for dragstrip bursts. 

But the most exciting possibilities lie on the electric side: The mix-and-match nature of Toyota’s hybrid system constitutes the very essence of tunability. The Prius controller and its computer chips were programmed to meet an operational profile that favors efficiency—with just enough Camry-like performance. Engineers could’ve tuned the system for even greater efficiency—or better performance—than the current mix.

Able to vary the mix from the dashboard, a Prius owner could have his cake and eat it, too: After a day of racing, he could turn a knob from “MEAN” to “GREEN”—or anywhere in between—for the drive home. The translucent knob, lit from within by red and green LEDs, would glow red at the MEAN setting, when only the red LED glowed. Turning the knob toward the other extreme, the red LED would progressively dim while the green LED came on and brightened. The knob would consequently glow red at the MEAN extreme and green at the other. It would glow yellow at the NORMAL midpoint of the knob's travel because equal parts of red and green light yield yellow.   

At the MEAN setting, the computer might push the motor past its rated power for brief periods—even doubling it—by feeding it more watts than normal. Motors and batteries are able to withstand brief periods of overload without damage due to overheating. Having the Prius’s zero-to-60 times to five seconds would require just a five-second burst of juice. 

Toyota isn’t the only one in the game: Honda has already shown high-performance concepts conceived around hybrid power. Toyota has put a considerable roadblock in the way of tuners, of course, by designing and burning its computer chips in-house, using nonstandard programming code. Still, I won’t be surprised if some laptop-wielding green meanie in Silicon Valley builds a black box that does the trick. Wouldn’t it be nice if Toyota Racing Development just saved us all he trouble by offering a tunable controller of its own?

Hybrid power shouldn’t be viewed as an engineering solution aimed only at saving gas and the ozone layer. As noted, electric motors make their maximum torque just above zero rpm, so it could be the future way to power-oversteer of car out of a corner or heat the skins prior to a quarter-mile assault. The potential exists to have cars that deliver scintillating performance, econocar fuel mileage, and squeaky-clean tailpipe emissions.

In other words, bring on the cake.

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