1983 Ford Probe IV - AllCarIndex

Official press release:

A dramatic new aerodynamic concept car unveiled by Ford Motor Company at the Detroit Auto Show (January 15-23) has the lowest coefficient of drag (Cd) of any conventional five-door vehicle in the world today, according to D. F. Kopka, vice president - Design for the company.

Called Probe IV because it is the fourth in a series of aerodynamic research cars created by Ford since 1979, the vehicle has a Cd of .15, which is roughly equivalent to that of a jet fighter plane.

Mr. Kopka said that if a typical passenger car of today had a Cd of .15, it would achieve 20 per cent better fuel economy at a steady 55 miles per hour. "In fact, it takes only 2.5 aero horsepower to move the Probe IV along a level highway at 50 miles per hour. A 1983 Thunderbird, which has one of the lowest Cd's on the road today, requires 6.2 aero horsepower to accomplish the same thing."

The Ford vice president said that the Probe is a conventional five-door sedan package. "Unlike most 'aero' concept cars that are shaped like bananas and hold only one passenger in a cockpit-like environment, Probe IV has room for four passengers and luggage, a conventional powertrain and a full array of convenience items usually found on passenger cars.

"Its interior reflects the same advanced level of design as the exterior," Mr. Kopka said, "with ergonomically designed controls that are within easy fingertip reach, maximum-visibility instruments and next-generation seating.

"Probe IV was developed through the combined resources and talent of Ford aerodynamics engineers, advance vehicle engineers, designers and Ford's Ghia studio in Turin, Italy, because it took a combination of exterior and under-the-skin innovations to achieve this remarkably low Cd."

The most striking exterior features include fully shrouded wheels, flush glass, covered headlights, concealed windshield wipers and a streamlined nose without cooling apertures — the radiator and air-conditioning condenser are located in the rear of the car.

It also has a full belly pan, a moveable front air dam that is deployed automatically depending on the speed of the car, and unique flexible front-fender skirts that screen out the wind but still allow the wheels to turn for steering.

Probe IV goes beyond sleek surface features to improve its aerodynamic drag with several important engineering innovations. They include automatic vehicle-attitude control, low-profile front-suspension system, a tilted engine for a low hood profile, and aerodynamically designed tires.

AUTOMATIC VEHICLE ATTITUDE CONTROL

Vehicle attitude is critical to obtaining the lowest possible Cd, and the optimum attitude varies at each speed because both vehicle height and the angle of attack change as the speed changes.

The Probe IV1s leveling system combines the advanced suspension system that will be on the 1984 Mark VII and air springs developed by Goodyear. For city driving at low to moderate speeds the car is six and one-half inches above the roadway. As the speed increases, the height decreases until at 40 miles per hour Probe IV is just four inches off the highway. At that point, the computer-operated front air dam automatically deploys to reduce the front-end height to three inches. At the same time, the rear of the car rises to six inches. The front deployable air dam has a manual override for operating on rough roads or for faster driving.

FLEXIBLE FRONT-FENDER SKIRT

To eliminate turbulence in the front-fender wells and still allow the front wheels to turn for steering, a flexible front-fender skirt was developed by Goodyear. It is made of the same kind of material as tires. A stationary skirt that is mounted over the wheel keeps the rotating wheel from coming in contact with the flexible membrane.

REAR-MOUNTED COOLING SYSTEMS

One of the most aerodynamically inefficient areas in a passenger car is the front grille opening. To alleviate this,

Probe IV's radiator and the air-conditioning condenser are housed in the rear luggage compartment, and their respective

air-intake openings are located behind the rear wheel wells. Electrically operated fans increase the air flow to the components and exhaust it out the rear, which also helps reduce negative air turbulence in that area of the vehicle. In fact, the exhausted air improves Cd by .005. The condenser and radiator are located behind the wheel wells so that they don't intrude into the luggage-storage space. The coolant for both components is routed to the front of the car through finned tubes which provide additional cooling.

LOW-PROFILE FRONT SUSPENSION

Because of the extremely low hood profile, conventional McPherson struts would have protruded above the hood line. Ford engineers designed a modified McPherson strut that is six inches shorter. However, the angle of the strut produced tremendous side loading which would have caused the shock absorber to bind. This was solved with a ball-bearing system that is practically frictionless .

The turbocharged 1.6-liter, four-cylinder CVH engine is tilted at a 70-degree angle to fit under the low sloping hood.

ADJUSTABLE CONTOURED SEATS

The unique front seats in the Probe IV permitted designers to lower the vehicle height by an additional 1.5 inches than would have been possible using conventional seating. A dramatic departure from the traditional straight-back design, they incorporate a special sling configuration which includes lumbar and thigh support that can be adjusted for a wide variety of individual pressure points.

AERODYNAMIC TIRES

Tire shape and size is an important part of managing the air flow around and under a vehicle. Ford designers worked with Goodyear to develop special tires for the Probe IV. The tread, which was designed by Ford engineers using a computer, has an aerodynamic pattern. The tire has a narrow profile and utilizes a Goodyear-developed compound that decreases road friction.

Engine & performance:

Position: front

Type: Ford Escort, 4-cylinder, Turbo

Capacity: 1598 cc

Power: 122 hp @ 5200 rpm

Torque: 163 Nm @ 3400 rpm

Dimensions:

Length: 4755 mm

Height: 1202 mm

Wheelbase: 2718 mm