The 600-lb stamped-steel and spot-welded space frame is being highly touted, although it is only a slight deviation from conventional unit construction. The primary difference is that none of the steel panels makes up the exterior body shell. That is comprised of easily fitted plastic outer panels, as described in the main story. The concept is very similar to the Corvette except for the precision-fit, mill-and-drill process. The percentage of plastic in the body structure is likewise similar to Corvettes with about 175 lb of sheet molded compound and reinforced reaction injection , molded (fiberglass) exterior panels.

Aerodynamics may not have been a high priority consideration in the original Fiero design. With a relatively low weight and small frontal area (by American standards), good EPA mileage figures were possible without going for the ultimate in low drag coefficient. The reported Cx is 0.377, which is not bad for such a short car, but not too strong an advertising point either. 

The obvious problem is the notchback rear window, which is almost a necessary evil in a mid-engine car. Although it allows easy engine access and ventilation, it really disturbs the upper air flow and increases drag while reducing potential down force from any rear spoiler. The Fieros other problem is the nose-up leading edge of the front bumper. This design allows a good open angle and radiator inlet, but it also rams a lot of air down under the nose. Not only does this usually increase drag, but it also generates a lot of lift, in spite of the bottom-breather radiator inlet. Reported front lift figures were about 120 lb at 100 mph, which can be significant when the static front weight is just over 1100 lb. It also appears that the opened headlight buckets were not as well researched in the wind tunnel as the Corvette's, as they raise the Cx to 0.417. Be that as it may, the pop-off plastic body panel concept means that better aerodynamics can be incorporated easily in the future.

The engine/driveline package doesn't provide much of a story this year. Basically it is GM's transverse 2.5-liter 4-cylinder sitting on a sub frame just as it does in the X-car. The cast iron overhead valve engine still puts out an everyday 92 bhp, even with an interesting new iron head casting. A swirl-port intake that brings the fuel-air charge into the cylinder along a spiral path makes its debut in the Fiero. New combustion chamber and piston dome shapes keep the charge swirling (and mixing) until ignition. This has allowed the compression ratio to be increased from 8.2 to 9.0:1, which is surprisingly good these days for an engine without a knock sensor.

Otherwise there are very few modifications to the driver line and sub frame assembly. The transverse transmission is available as either a 3-speed automatic with lockup converter and 3.18 final drive, or a 4-speed manual with top gear ratio options. Only the "performance" ratio with a 4.10 final driver is of interest to the enthusiast, as the 3.32 gear coupled with a 0.73 4th gear is suitable only for economy runs. The X-car axles are used as-is, including the constant-velocity outer U-joints.

The engine sub frame, however, is not a straight interchange with the X-car. At the rear, the rails had to be kicked up to provide a better rear ramp angle. (In the front-drive X-car these rails connect to the floor pan at the firewall.) And the front rails have had the mount bushings rotated from a horizontal plane to a vertical plane. This allows the sub frame to pivot downward about the front mount bolts for easier engine removal. To absorb engine torque reactions, an upper strut connects the cylinder head with a sheet metal bracket on the right shock tower. All of these sub frame and strut mounts are well insulated with rubber bushings, which are great for isolating road and engine vibrations from the passengers, but don't do a lot for handling.

The front suspension is taken almost in total from the Pontiac T-1000. Although not originally designed for a sports car the particular short- and long-arm configuration is not to bad in this application. The major modifications were to widen the interconnecting sub frame to give a 2-in wider track and to relocate the shock absorber mounts. On the T-car the shock mounts to the upper arm and stands very high in the wheel well. Therefore to lower the Fieros hood line, the shock now mounts to an otherwise standard lower arm. Basically this is a good design, especially with the contemporary practice of leading steer arms but somewhere in the translation a little too much bump steer seems to have been allowed, causing more steering wheel feed back than we are used to.

Part of the feedback can be attributed to non-assisted steering --- which I prefer. Early in the design it was decided that the low front weight made assisted steering unnecessary in most circumstances. The worst situation is parallel parking with the optional wide tires. In this case the effort is noticeable thought not unreasonable.

At the rear, the suspension is essentially indistinguishable from the X-car's front layout. Even the trailing steer arms are there, although in the Fiero they are anchored to the sub frame via tie rods that can still be adjusted for toe-in. The combination should give excellent cornering compliance under steer qualities. Only a couple of really finicky evaluators have perceived slight yaw overshoot, which could be because of lateral 
/bounce/ compliance in the engine/suspension sub frame. Otherwise the handling properties are excellent, with an easily corrected drop-throttle overseer when cornering at the limit. The average roll angle of 3.5 degrees per G is reasonable, considering the front anti-roll bar is only 23.0 mm and there is none at the rear. The wide track helps, naturally, but not the reported 19.5-in center of gravity, which seem high for a car this size.

A new disc brake system also appears for the first time on the car with Pontiac's adapting two existing front suspension systems to the front and rear of this car results in 4-wheel discs, but not steel calipers. Because the rear requires a mechanical emergency brake, a standard front caliper could not be used. These new single-piston aluminum calipers are essentially identical front and rear, except for the rear emergency brake balance. A conventual's proportioning valve limits rear wheel lockup, although the Fiero may have almost the ultimate configuration for ideal braking. Given the static rear weight bias, and the reported wheelbase ratio, the forward weight shift in breaking will give excellent dynamic balance. Other braking advantages in the layout are the central fuel tank, central seating and minimal luggage capacity. This means that no matter how the car is loaded, the optimum brake balance will hardly vary.

A lightweight car without a power assisted steering option, you might ask why power assisted brakes are standard. The first information given was a lack of space in the pedal area for the mechanical leverage. A second reason was an unexpected "knock-back" problem with the 4-wheel discs, which use so much pedal travel. One hopes this will be sorted out eventually, allowing a non-boosted system and the resultant better response.

The standard wheels and tires are fairly conventional P185/80R-13 steel radials on 5 1/2in wide steel rims. These provide low rolling drag for fuel economy and contribute to the low base price. However, those hoping to upgrade the appearance of the Fiero will opt for the same-size turbo-finned aluminum rims. And true enthusiasts will demand the "high-tech" 14 x 6in aluminum wheels with P215/60R-14 Eagle GTs. There appears to be plenty of room for expansion in the wheel wells. Pontiac engineers present at the introduction confessed that they hope to have a 50-section tire option available next year. Of course, even if the extra-wide wheels didn't fit, it wouldn't be difficult to add optional flared fender panels.

The optional Eagle GT's are the main ingredient in the WS6 special performance package, which also includes stiffer front springs, stiffer front and rear shocks, stiffer rubber mounts and bushings but no change in the standard front anti-roll bar. For quicker steering response, the steering rack is mounted more rigidly, and a rubber link in the steering shaft is stiffer.

The stated goal in the performance package was to make the Fiero equivalent in every respect to the Firebird WS6 option, but it was fairly obvious that they hadn't met that objective. The transient response is excellent, though not exactly what you might like in a true sports car. The problem in transferring handling technology from the Firebird is the basic difference in weight distribution and wheelbase. With springs bushings selected to avoid vibrations and freeway pitch oscillation, this doesn't allow much flexibility for response tuning---so far.

370,167 Fieros rolled off the production line in its short-lived life from 1984 to 1988. And thanks to a few of the '84s equipped with the "Iron Duke," it sooned earned the reputation of being a fire-prone econobox. However, to the disappointment of many Fiero antagonists it received high safety ratings and managed to avoid the menacing fires