Scion IQ has a lot to say about packaging

  • 09-Jan-2012 04:21 EST
scionIQlead.JPG

The Scion IQ has stubby look, but careful shaping produces a 0.31 Cd.

The Scion IQ is a midsize entry—in the micro-subcompact class, that is. At 120.1-in (3051 mm) overall with 3-4 seating, it's right in between the Smart fortwo (106.1-in/2695 mm) and the Fiat 500 four-passenger (139.6-in/3546 mm). Like the others in its class, the IQ is a niche vehicle in the U.S. market, but it's a showcase for advanced packaging technology that provides usable space beyond what could be expected from its dimensions.

Toyota says the IQ is the shortest mass-production four-seater sold in the U.S. And although it doesn't reach the magic 40 mpg number in highway driving, it actually has the highest combined U.S. EPA fuel economy for a nonhybrid: 37 mpg (36 city/37 highway). The stubby look notwithstanding, the body has been shaped for a relatively low 0.31 Cd.

The 3-4 seating is in large part attributable to the innovative interior design. The front seating is asymmetrical, with the passenger seat forward of the driver's seat, enabled by a dashboard that curves forward (away from the front passenger). This leaves good legroom for the front passenger, and with that seat moved forward there is compact-class rear seat legroom in the seat behind for a third occupant. The forward curve was permitted by removing the glove box and instead providing storage in a drawer under the passenger's seat, and by reshaping the HVAC system. Further, the front seat tracks are integrated into the floorpan, which increases foot space for rear passengers.

In a conventional HVAC system, the blower case is above and behind the glove box on the passenger's side. In the IQ, the blower is a compact design that is integrated with the main section HVAC case (located primarily behind the center stack), which also holds the heater core and A/C evaporator. Further, the cabin air filter is thinner and also moved into the main section, so little more  than the airbags are in the dashboard on the passenger's side. The HVAC system is supplied by Denso.

The front seatbacks are thin designs, which also increases the space available for the occupants, although the amount for the fourth passenger (in the rear on the driver's side) is limited and depends on how much is required by the physical stature of the driver and his chosen position. At the least it is adequate for a child.

The IQ is relatively wide, 66.1-in (1679 mm), 59.1-in high (1501 mm), and on a 78.7-in (1999-mm)wheelbase, so the wheels obviously are pushed out as close to the four corners of the car as possible. This not only gives the car a broad look, but in the rear increases the seat width space (hip room). The result is a cabin that is almost as wide as a larger vehicle's, such as a Toyota Corolla or Scion xD, and there is no claustrophobic effect, even for the third passenger.

To provide an enhanced safety image, the IQ has 11 airbags as standard equipment, including an industry-first rear window area airbag.

The vehicle weighs just 2127 lb (965 kg), and the performance from the 1.3-L four-cylinder—rated at 94 hp (70 kW)—is reasonably lively. It provides a 0-60 mph (0-97 km/h) time of 11.8 s, with a top speed of 100 mph (161 km/h). The engine is mated to a steel-link belt-type CVT (continuously variable transmission), with a torque converter and early-lockup converter clutch. The CVT itself has a forward clutch that when disengaged provides a true neutral for fuel economy when the car is being stopped in D (drive) on a level road. If it's on an incline, as determined by an algorithm from the skid control computer, the forward clutch remains engaged for safety.

The CVT has two additional driver-selectable forward ranges: "S" that can keep the CVT in lower and mid-speed ratios for engine response in hard cornering, and "B" to provide low ratios for more engine braking when going down steep hills. The CVT operates smoothly, vs. the lurching character of an electro-hydraulically shifting transmission—a complaint about the fortwo. The U.S. model of the Fiat 500 also dealt with this issue, but by installing a conventional six-speed automatic.

The IQ powertrain also is in the midpoint of the micro-subcompact class. The engine's 94 hp (70 kW) rating compares with 70 hp (52 kW) for the1.0-L three-cylinder in the fortwo and 101 hp (75.3 kW) for the 1.4-L in the Fiat 500.

A micro-subcompact can be expected to have a small turning circle diameter, but the IQ's 25.6 ft (7.8 m) is smaller than the fortwo's and 500's. In part, this is because of the powertrain compartment packaging. The engine is a narrow, compact design that allows deeper wheel wells, so the steering knuckles can permit the wheels to turn at sharper angles. The compartment itself is narrow north-south, a space-saving layout that includes integration of the radiator fan and shroud, air filter housing, powertrain computer, and coolant reservoir into the front cooling module. Because the wheels are nearly at the edges to minimize overhang for a larger cabin, a unique differential was required. It's a compact design that mounts forward of the engine and transmission.

The narrow compartment left no space in the powertrain and front suspension areas for the steering rack, so Toyota mounted it high at the back, close to the bulkhead, with tierods that go down to reach the steering arms. The IQ has electric power steering assist, with the motor on the steering column. Front suspension is MacPherson strut; rear suspension is the inverted torsion beam type, with the rear shocks canted back and outward to increase rear-seat hip room.

Cargo space with the rear seat backs up is limited to 3.5 ft³ (99 L), a modest number derived from a clearance of about 5 in (127 mm) between the rear seat and the tailgate. The rear seatbacks individually fold down, creating a more generous area of up to 16.7 ft³ (473 L). It's no surprise there instead of a spare tire there is a repair kit and inflator to save space and weight.

The rectangular plastic fuel tank is just 8.5 gal (32 L) in volume and 4.72 in deep (120 mm) and on the left side under the driver's seat and the footwell of the left rear passenger position. This compares with the conventional, taller, boxy shape, typically just inboard of the rear axle and partly under the rear seat. This new shape and location shields it in case of an accident and also improves rear-seat passenger room.

The IQ is priced at $15,995 (including delivery) and there are no factory options. However, 16-in alloy wheels (to replace 16-in steel wheels that are standard), a lowering kit, rear spoiler, fog lamps, premium audio, etc., are available as port-of-entry or dealer-installed accessories.

The IQ is being launched in stages, now on the West Coast, early 2012 in the Southeast and Gulf states, then New York, and by spring in the rest of the country.

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