During development of the Sequoia full-sized sport-utility, chief designer Kaoru Hosokawa spent 179 days a year in America. The reason for such a precise cutoff: Any more time would have triggered income-tax consequences.
But his level of commitment to Toyota's biggest vehicle destined for sale in America meant he had to be in touch with the market. As the product came closer to fruition, Hosokawa spent all of March, April and May in Indiana, helping the factory get ready for Job 1. At the press launch in Montana in September, Hosokawa spoke with Staff Reporter Mark Rechtin about the details of creating the Sequoia.
As a chassis engineer, what were some of the trade-offs you faced in designing a big sport-utility?
Our first priority was with steering, in having precise handling. The steering feel around neutral initially was vague with the big tires, but we wanted passenger-car performance. With the brakes, it is difficult to get good feedback because the vehicle is so heavy; it is difficult to engineer pedal stroke versus effort versus performance, but we felt braking performance should increase as more pressure is given. We evaluated the Expedition, M class and Land Cruiser and also talked to our American staff. Americans tend to like stiffer brake pedal feel, which is worse for an SUV because then you have a compromise between pedal feel and performance. But we made the pedal feel stiff, especially midway through pedal stroke. At the same time, Americans like their throttle feel to be linear, and we carried that over from the Tundra.
How did you tune the suspension for off-road ability compared with cruising comfort?
We wanted good ride comfort and (noise, vibration and harshness), but at the same time the suspension had to be stiff for a sport-utility. So we combined the stiffness of the chassis frame with the stiffness of the shell body. We measured the Sequoia against the Land Cruiser and Expedition, and we have higher body stiffness than the Expedition when you combine the frame and the body. We have not judged the Expedition's chassis by itself. But the Sequoia is less stiff than the Land Cruiser, because that has to be the toughest vehicle in our lineup.
Why use vehicle skid control and traction control instead of a limited-slip differential?
The technical origin of our skid control and traction control comes from the antilock brake system, and from the beginning we wanted ABS to be standard. So it was easy to advance that technology. We wanted our system to have the same performance as a limited-slip differential. If ABS weren't standard, then it might be a different story with having a limited slip. However, we would have had to change the ABS tuning if we had used a limited slip.
What parts are shared with the Tundra?
The engine and transmission are the same, but the transmission computer for the shifting schedule is different. The propeller shaft also is different. The front suspension structure is similar to that of the Tundra, but the rear suspension was newly engineered for the Sequoia - more similar to that of the Land Cruiser and 4Runner.
The Tundra has a bench seat. Was there ever a plan for one in the Sequoia?
At the beginning stage, I thought that it was necessary. But in discussions with Toyota Motor Sales U.S.A., they felt otherwise. They said Expedition sells less than 5 percent bench seats.
If no bench seat, then why a shifter on the steering column? Why not a shifter through the center console?
The Tundra has no floor shift either, and its low range is automatically done with a switch on the dashboard. It also is more difficult to put a shift lever in the floor, and we needed to share those parts with Tundra, so it was decided to be a column shift.
Was there ever a thought of a V-6 version to lower the entry price?
The Tundra has a V-6 and the 4Runner does, too. But in looking at the American market, we saw we could only develop a V-8 in the time we had. We also knew that the increased weight of the Sequoia compared with the Tundra would result in the V-6 being too weak. Even though we could have made it an entry model, we didn't want to have reduced engine performance.
If this is a vehicle meant only for American consumption, why was it designed in Japan?
It was mostly done by Japan, but we also consulted with Calty designers (from Toyota's design center in Newport Beach, Calif.) about the styling. There were discussions every month between Japan and America when we were preparing the rendering and clay models.