Jaguar's 1989 sedan range shows a marked improvement in standing start acceleration over the 1988 model, due to increased engine performance and a new rear axle ratio. Careful matching of the characteristics of the engine and axle have enabled Jaguar engineers to reduce the 0 to 60mph figure from 10.4 seconds to 9.6 seconds without significantly increasing fuel consumption.

A number of other changes are also introduced for the '89 model year, chief among which are passive front seat belts.When the new generation of 1988 Jaguar sedans was introduced to the American market, they were supplied with a fuel-saving 2.88 to 1 rear axle ratio and equally economical low-compression (8.2 to 1) engines. Customers' desire for more low-end acceleration prompted a change to 9.6 to 1 compression that added 8 percent to the horsepower rating (from 181 to 195) with no fuel economy penalty, but which required premium fuel.

For 1989, in addition to the high compression engine Jaguar XJ6 and Vanden Plas sedans are equipped with the European 3.58 to 1 rear axle ratio.

The effect of the new axle ratio, combined with the increased power and torque, is to give the `89 XJ6 and Vanden Plas Jaguars acceleration figures that put them among the leaders in their class.

"We wanted to achieve improved acceleration, but not at the expense of Jaguar's reputation for smoothness and performance with economy," said Graham W. Whitehead, president of Jaguar Cars Inc. "With combined EPA figures of 22.8, we've accomplished that objective."

Another major change for the 1989 model year is the adoption of passive restraint systems for the front seat occupants, in line with federal legislation. Shoulder belts move into position as the doors are closed, leaving the lap-belt to be fastened manually.

The point at which the shoulder belt finishes its travel is moveable, enabling drivers and passengers of varying heights to adjust it to their individual requirements, providing considerably more comfort. An additional advantage is that a belt that is individually set to fit the occupant correctly can give better protection.

Added driver convenience comes with a remote-controlled door-lock system in which an infra-red transmitter carried on the key ring is used to unlock the car from a distance.

Styling changes for the 1989 cars are minimal, designed to further "fine-tune" the individual Jaguar styling that was so well received when the new sedans were first introduced in May 1987.

A new finisher plate below the windshield bridges the gap between the hood and the shield, and the washer nozzles are raised.

These changes, combined with restyled door mirrors that further reduce wind noise, give this area of the car a sleeker look. Other exterior changes are new trunk badges and the deletion of the black finish on the rear panel of the Vanden Plas model.

Changes to the dash board continue the "fine-tuning" theme, with a new LCD read-out for the clock, an improved method of operation for the cruise control, and modifications to the unique Jaguar Vehicle Condition Monitor, which monitors important aspects of the car's functions and warns of malfunctions or need a fascia-mounted screen.

XJ6 and Vanden Plas versions of the car continue to be offered, the Vanden Plas version being equipped with a number of luxury features including the veneered picnic tables, fitted fleece-like passenger floor mats, rear seat reading lamps and additional exterior chrome trim.