Pontiac Fiero
From Wikipedia, the free encyclopedia
| Pontiac Fiero | |
 |
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| Manufacturer: | Pontiac |
|---|---|
| Parent company: | General Motors |
| Production: | 1984–1988 |
| Successor: | Pontiac Solstice |
| Class: | Sports car |
| Body style: | 2-door notchback 2-door fastback |
| Layout: | MR layout |
| Platform: | GM P platform |
| Engine: | 2.5 L Iron Duke I4 2.8 L V6 |
| Transmission: | 4-speed manual 5-speed Isuzu & Getrag manual 3-speed TH-125 automatic |
| Wheelbase: | 93.40 in. |
| Length: | 4072 mm (160.3 in) |
| Width: | 1750 mm (68.9 in) |
| Height: | 1191 mm (46.9 in) |
| Curb weight: | 1176 kg (2590 lb) to 1265 kg (2790 lb) |
| Similar: | Fiat X1/9 Toyota MR2 Matra Murena |
| Designer: | Hulki Aldikacti |
- Fiero redirects here. A DC Comics character also is named Fiero.
The Pontiac Fiero is a mid-engined sports car that was built by the Pontiac division of General Motors from 1984 to 1988. Today, the car has a large cult following, making it a prime example of a cult car.
Contents |
[edit] Brief history
Once a dream originally envisioned by John DeLorean, inspired by his Pontiac Banshee prototype, the Fiero -- meaning "proud" in Italian -- was finally designed by Hulki Aldikacti as a Pontiac sports car. Other names considered were Sprint, P3000, Pegasus, Fiamma, Sunfire, and Firebird XP. Because of a "cool" reception by GM management and accountants, it was finally marketed to GM as a fuel-efficient commuter car. The public, however, had other ideas for the only mid-engined car ever mass produced in North America. The Fiero was also the first 2-seater Pontiac made since the 1926 to 1938 coupes, and until the 2006 introduction of the Pontiac Solstice. The sports car potential of this car was greatly reduced due to cost-cutting however, and came under fire from critics because its publicity did not match its initial performance. Though originally designed with its own suspension and brakes, ultimately off-the-shelf components were used, which severely limited the Fiero's performance envelope. [citation needed]
By the end of production, the Fiero had received the original suspension design but kept a limited offering of engines — the use of turbochargers or the newer DOHC straight-4 engines, never made it to production. Officially, production ended because of insufficient profits. Budget constraints on Pontiac forced them to borrow parts from other models rather than use the suspension originally designed by the engineers. For example, some of the front suspension was taken from the Chevrolet Chevette's [1] double A-arm design, allowing the wider and low-slung Fiero to handle exceptionally well (though at a cost; the Fiero shared front wheel bearings with the Chevette, and the Fiero's greater weight, wider tires and tendency to be driven like a performance car resulted in short bearing life). On the other hand, Chevette enthusiasts routinely upgraded their notoriously undersized brakes and rotors using Fiero parts. The rear suspension and base drivetrain was almost identical to the front end of GM X-body cars like the Chevrolet Citation and Pontiac Phoenix - the Fiero even included rear tie-rod ends for alignment, though they would have been used for steering had that particular assembly been used in an X-car.
[edit] Engine fire reputation
The fires, which affected almost exclusively the 2.5 L engine, and mostly '84 models at that, were due in some cases to the engine wiring harness being located above the exhaust manifold, with a notoriously leaky valve cover in between. Most valve covers leak oil onto the exhaust manifold eventually. If the wiring falls onto the exhaust manifold, or somehow shorts against it, it often ignites the oil that has leaked onto the back of the engine. Also, the 1984 model had a magnesium grille over this area. In later models, this was corrected to some degree with much better heat shielding. This issue was with the 1984 models.
The primary cause of engine fires was poorly cast connecting rods failing under infrequent oil changes. The faulty connecting rods were produced in GM's Saginaw plant. As the "Iron Duke" engine was a relatively long-stroke four cylinder engine, it produced most of its power in the low revolution ranges. In most vehicles, this is not a problem, but there were two schools of thought concerning the Fiero.
One theory is that the sports car styling attracted buyers who would drive the car hard, most notedly over-revving the engine. The long-stroke geometry of the Iron Duke makes it less suitable for high RPM operation, most noted by GM calibrating the tachometer redline at 5000 RPM. The reason GM designed this engine to produce the power in the lower RPM band is because the car was originally intended as an economy commuter that didn't look like the other boxes on the dealership lots at the time.
Another factor was the 3 quart capacity oil pan, coupled with the then-stock specified AC-Delco PF-47 oil filter, and the leaky valve cover gasket. If proper oil level was not maintained, the bearings would seize, snapping the porus castings of the connecting rods resulting with punched holes in the engine block, thus spraying oil onto hot exhaust components where it could ignite.
However, most vehicles existing today have been serviced by GM during one of the safety recalls on the car. On the fire-related recalls, shields and drip-trays were added to prevent leaking fluids from contacting hot surfaces. The presence of drip shields between the engine block and the exhaust manifold are a good clue that the car was retrofitted. The addition of the longer AC Delco PF52 oil filter, commonly found on other models, like the V6 Chevrolet Camaro and Pontiac Firebird, as well as the Chevrolet Astro Van, added extra oil capacity to the oiling system.
[edit] Cooling system issues
With the mid-mounted engine and long pipes carrying coolant to the front-mounted radiator, the Fiero was also prone to overheating if the cooling system had not been properly filled. Simply pouring coolant into the thermostat housing (on the engine) would leave a large bubble in the radiator, while adding coolant to the radiator would cause a large bubble in the engine's coolant passages. Proper procedure (filling the thermostat housing, then burping the bubble out of the radiator by cracking open radiator cap until coolant exits) must be followed in order to ensure an air-free cooling system.
A second problem has become common as more Fieros are being serviced by shops unfamilier with their design. The under-body coolant tubes are positioned in such a way that a casual glance beneath the car will not suggest their fragility. As a result, many have been crushed by the shop lifts, resulting in a near complete lack of engine cooling. The age of the car means that even GM dealerships may be unaware of the proper jacking methods.
[edit] Suspension design
The front end of the car is a wider direct derivative of the Chevette. A double A-arm (or double wishbone) design common prior to MacPherson struts, it has naturally good geometry. But it also has four ball joints on the front and another four tie rod ends. The tie-rods allow toe-in/out adjustability. Minimal camber adjustments exist on 84-87 models without an after-market upgrade available from MOOG that replaces the upper ball joints with slotted mounting points units. The joints have typical grease fittings for regular lubrication typical on pre-2000 autos.
The rear suspension is essentially a GM X-car's front suspension moved to the rear of the Fiero. The uppers are top-plates and MacPherson struts, while the lowers are attached with ball joints. In lieu of the steering rack which would have been installed in an X-car, tie rod ends are attached to the engine cradle and used to align the rear wheels.
The overall design provides an extremely good independent suspension to all wheels, built with GM's off-the-shelf parts. Maintenance is required on most vehicles, as they predate modern sealed ball joints. Should one ball joint require replacement (evidenced by any detectable wobble in a ball joint when the wheel is in the air), it is prudent to replace all six ball joints and all eight tie rod ends in the car; otherwise, the requisite four wheel alignment would be a waste of money after the inevitable and imminent replacement of the next ball joint.
With the 1988 model year came a completely new front and rear suspension with vented disc brakes at all four corners- what Pontiac's engineers had planned for the car to have from the beginning. The front suspension geometry was changed to decrease the scrub radius thus decreasing steering effort without adding a bulky power steering system. The camber curve was also much improved, the dampers are moved inside the coil springs, and new sealed bearing/hub units were used (unique to the 1988 Fiero, to the dismay of many owners seeking repair or restoration). The rear suspension featured multi-link (two lateral links and one trailing arm) MacPherson strut suspension, and the bump steer experienced with the earlier suspension design was fixed. The brakes were also upgraded to 10.5" vented rotors on the front and rear with an improved slide caliper design. The Fiero Formula (new for 1988) and Fiero GT models also received a rear swaybar.
An important note is that the 84-87 frames will accept a 1988 rear cradle. However the struts must be replaced with a narrower diameter Carrera coil-over unit with a steel tube extension and offset mounting plates added to replace the MacPherson strut unit. Thus yielding a larger, 84-87 engine compartment with the tremendous ride-quality benefits of the 1988 suspension.
In the August 1985 issue of Road & Track, the Fiero was tested against 6 other sports cars. The slalom results (MPH): Honda Civic CRX Si: 62.5 Toyota MR2: 61.6 Pontiac Fiero: 61.5 Alfa Romeo Graduate: 58.4 Bertone X1/9: 58.3 Mazda RX-7 GSL: 57.2
[edit] Today
Currently the Fiero has a strong following of owners and customizers. Because of an abundance of replacement parts available from other General Motors vehicles, there are many upgrades that can be done to improve performance and reliability of the cars. Additionally, a multitude of different General Motors engines have been installed by enthusiasts, from the Quad-4 engine to the Chevrolet small-block V8.
The Fiero 2M4 (2-seat, Mid-engine, 4-cylinder) was on Car and Driver magazine's Ten Best list for 1984. The 1984 Fiero was the Official Pace Car of the Indianapolis 500 for 1984, beating out the new 1984 Corvette for the honor.
A large following of owners still exists with many web pages, groups, and clubs devoted to the car, and the basic chassis is commonly used as a kit-car platform from wild custom rebodies to Ferrari F355 replicas.
[edit] Transmissions
[edit] Automatics
All automatic-equipped Fieros were equipped with the three-speed TH-125 with torque converter lockup.
Automatic transmission final drive ratios:
- I4
- 1984-1986: 3.18
- 1987-1988: 2.84
- V6
- 1985-1986: 3.06
- 1987-1988: 3.33
[edit] 4-speed manual
All 4-speed manual transmissions were built at the Muncie, Indiana Allison plant. The 1984 production line saw two transmissions, a performance 4-speed with a final drive ratio of 4.10, and an economy 4-speed with a final drive ratio of 3.32. The V6 on the 1985 model and part of the 1986 production year came with a 4-speed with a final drive ratio of 3.65.
[edit] 5-speed manual
Isuzu and Getrag-produced 5-speed transmissions were available, depending on model and equipment (The "getrag" actually being a Muncie built transmission based on a Getrag design). The Getrag 282 is the stronger unit, designed for use with the higher output of the V-6.
[edit] Manual transmission gear ratios
| Year | Style | Code | Axle | 1st | 2nd | 3rd | 4th | 5th | rev. |
|---|---|---|---|---|---|---|---|---|---|
| 1984 | econo 4 speed | MY8 | 3.32 | 3.53 | 1.95 | 1.24 | 0.73 | — | 3.42 |
| 1984 | perf 4 speed | M19 | 4.10 | 3.53 | 1.95 | 1.24 | 0.81 | — | 3.42 |
| 1985 | V6/4-speed | M17 | 3.65 | 3.31 | 1.95 | 1.24 | 0.81 | — | 3.42 |
| 1985 | I4/5-speed | MT2 | 3.35 | 3.73 | 2.04 | 1.45 | 1.03 | 0.74 | 3.50 |
| 1986 | V6 4 speed | M17 | 3.65 | 3.31 | 1.95 | 1.24 | 0.81 | — | 3.42 |
| 1986 | V6 5 speed | MG2 | 3.61 | 3.50 | 2.05 | 1.38 | 0.94 | 0.72 | 3.41 |
| 1988 | I4/5-speed | MT2 | 3.35 | 3.73 | 2.04 | 1.45 | 1.03 | 0.74 | 3.50 |
| 1988 | V6/5-speed | MG2 | 3.61 | 3.50 | 2.05 | 1.38 | 0.94 | 0.72 | 3.41 |
[edit] Production years
[edit] 1984
1984 was the first production year for the Pontiac Fiero, which began production in August 1983 for the 1984 model year. In an effort to sell the car as being economically sensible, GM equipped and sold the Fiero as a commuter car but the marketing build up leading to initial release indicated anything but a regular commuter car. The car also proved uncomfortable for some drivers because of the lack of power steering.
The 1984 was the only year in which the Limited "Indy Pace Car" edition, consisting of an Indianapolis 500-themed option package on SE-model vehicles, was offered. Approximately 2,000 of these vehicles were sold. The Indy had aero body cladding and new front and rear fascias that would be used on the 1985 GT. Only the underpowered 4-cylinder engine was available (though a few prototypes could be seen driving around the Greater Detroit area with a unique periscope-style inlet sprouting from the engine compartment and curving up and over the roof. This "periscope" style inlet was used on the actual Indy Pace Car Fieros that at the 1984 Indianapolis 500. This inlet scoop, and the 2.5 liter Super Duty engine that they fed were not available on the production model pace car replicas.
| VIN | Style | Cars produced |
|---|---|---|
| 1G2AE37RxEPxxxxxx | Fiero | 7,099 |
| 1G2AM37RXEPxxxxxx | Fiero Sport | 62,070 |
| 1G2AF37RxEPxxxxxx | Fiero SE or Indy | 65,671 |
| Total production | 136,840 | |
[edit] 1985
In 1985, the problem with insufficient power was first addressed, much to the satisfaction of the general public. A Chevrolet 2.8 L V6 engine rated at 140 hp (104 kW) was put into the car, satisfying most critics of the base engine. The High Output V6 was paired with a modified Muncie 4-speed transmission. The 4-cylinder engine (known as the "Iron Duke") was now paired with the Japanese-designed Isuzu 5-speed (also produced at the Muncie, Indiana plant).
| VIN | Type | Cars produced |
|---|---|---|
| 1G2PE37R#FP2##### | Fiero | 5,280 |
| 1G2PM37R#FP2##### | Fiero Sport | 23,823 |
| 1G2PF37R#FP2##### | Fiero SE (I4) | 24,724 |
| 1G2PF379#FP2##### | Fiero SE (V6) | |
| 1G2PG379#FP2##### | Fiero GT | 22,534 |
| Total production | 76,371 | |
[edit] 1986
1986 was the first year the fastback was offered. Also offered late in the production year was a 5-speed Getrag transmission (coupled only to the V6 engines). Models equipped with the 4-cylinder engine remained largely unchanged. The clutch hydraulic systems were redesigned with new master and slave cylinders.
| VIN | Type | Cars produced |
|---|---|---|
| 1G2PE37R#GP2##### | Fiero | 9,143 |
| 1G2PM37R#GP2##### | Fiero Sport | 24,866 |
| 1G2PF37R#GP2##### | Fiero SE (I4) | 32,305 |
| 1G2PF379#GP2##### | Fiero SE (V6) | |
| 1G2PG379#GP2##### | Fiero GT | 17,660 |
| Total production | 83,974 | |
[edit] 1987
1987 had minor modifications to the front and rear fascias on the "base coupe" with the SE & GT models keeping the same "Aero" nose. The 4-cylinder's power rating increased to 98 hp (73 kW) with some major modifications which included a roller cam, redesigned intake manifold, distributorless ignition system, open combustion chamber cylinder head and upgraded throttle-body fuel injection system. This was the last year for the spin-on oil filter on the 4-cylinder. The car was offered in Medium Metallic Blue and replacing the ribbed black moulding was the round style found on the GT models. As a side note, the SE models retained the ribbed moulding, and added the aero nose found on the GT. Redesigned headlight motors appeared in 1987. Additionally, starting with the 1987 model Pontiac dealerships offered an upgrade in the form of an "option" that changed the original body to a Ferrari-type body, called the Fiero Mera. While technically a "kit", the change in body style was offered only on new Fieros and is considered a class of car in its own right. There was a limited production of Fiero Meras made however, as the company that produced them, Corporate Concepts, was sued by Ferrari and ordered to stop.
| VIN | Type | Cars produced |
|---|---|---|
| 1G2PE11R#HP2##### | Fiero | 23,603 |
| 1G2PM11R#HP2##### | Fiero Sport | 3,135 |
| 1G2PF11R#HP2##### | Fiero SE (I4) | 3,875 |
| 1G2PF119#HP2##### | Fiero SE (V6) | |
| 1G2PG119#HP2##### | Fiero GT | 15,968 |
| Total production | 46,581 | |
[edit] 1988
The 1988 Fiero brought a new suspension design, thought by many to have a striking resemblance to those designed by Lotus, which at the time, was about to be acquired by General Motors. The suspension was never a Lotus design though - it was the suspension the Pontiac engineers had designed in the beginning. The 4-cylinder engine received an in-pan oil filter element and balance shaft and a more powerful V6 was available. A "Formula" option was added, which offered many of the GT features with the standard coupe body. 1988 marked the end of production for the Fiero, and ironically is also considered to be the best Fiero produced. Improvements to suspension, brakes, steering, and improvements to both the four-cylinder and V6 engines took the car to a level far beyond the 1984 model that had received much criticism. Also 1988 was the only year T-tops were an option through dealerships, and the only year a yellow exterior color was available from factory.
| VIN | Type | Cars produced |
|---|---|---|
| 1G2PE11R#JP2##### | Fiero | 23,603 |
| 1G2PE119#JP2##### | Fiero Formula | 15,968 |
| 1G2PG119#JP2##### | Fiero GT | |
| Total production | 39,571 | |
[edit] 1990
A never produced 1990 Fiero Prototype has been displayed at a few major shows. Much of its design influence was found in the fourth-generation Firebird. Other engines were proposed, right up to a factory installed V8 that is rumored to have been seen at a test track. The only 1990 Fiero came equipped with a turbocharged V6 engine making 205 hp, found in the Pontiac Grand Prix, the GEN II v6 of the day. Critics of the axing of the Fiero model claim this model would have been faster, quicker, better handling, and cheaper than the Corvette. GM cited slumping and unprofitable sales of the Fiero as the reason for its demise following its 4th model year.
| VIN | Type | Cars produced |
|---|---|---|
| 1G2PE11x#KP2##### | Fiero | 1 |
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[edit] References
- Witzenburg, Gary. Fiero:Pontiacs Potent Mid-Engine Sports Car. Motorbooks International Publishers. Osceola, WI 1990.
