Engine swaps
Engine swaps are one of the most common major modifications performed on the Pontiac Fiero.
Because the Fiero has a mid-engine layout, a removable rear cradle, and an active enthusiast community, many owners have replaced the factory engine with other GM engines or custom drivetrain combinations.
Overview
The Fiero was originally available with the 2.5L Iron Duke four-cylinder engine and the 2.8L V6. Engine swaps are often performed to increase power, improve drivability, replace a worn original engine, or create a custom build.
Engine swaps vary widely in difficulty. Some use engines from related GM platforms, while others require extensive fabrication, wiring, exhaust work, mounts, transmission adaptation, cooling changes, and tuning.
Common engine swaps
Commonly discussed Fiero engine swaps include:
- 3800 swap
- 3800 Series II swap
- 3800 Supercharged swap
- 4.9 Cadillac swap
- Northstar swap
- LS4 swap
- Ecotec swap
- 3.4 pushrod swap
- 3.4 DOHC swap
- Small-block Chevy swap
Planning an engine swap
An engine swap should be planned carefully before parts are purchased or the original drivetrain is removed.
Important considerations include:
- Engine choice
- Transmission choice
- Engine mounts
- Cradle modifications
- Wiring harness
- ECM or PCM
- Fuel system
- Cooling system
- Exhaust system
- Axles
- Clutch or torque converter
- Emissions requirements
- Serviceability
- Budget
- Intended use
Transmission choices
Engine swaps often involve decisions about whether to retain the original Fiero transmission, use a different manual transmission, or use an automatic transmission matched to the donor engine.
Related topics:
- Transmission
- Getrag 5-speed
- Isuzu 5-speed
- Muncie 4-speed
- TH125 automatic
- F40 6-speed
- 4T65E-HD
- Axles
- Clutch
Wiring and engine management
Wiring and engine management are major parts of many engine swaps. The swap may require adapting a donor engine harness, modifying the Fiero harness, changing the ECM or PCM, disabling unused donor-car systems, and integrating gauges, fuel pump control, charging, diagnostics, and cooling fan control.
Related topics:
Cooling and exhaust
Engine swaps may require changes to the cooling system and exhaust system. Exhaust routing, heat management, coolant hose routing, and radiator capacity should be considered during the swap.
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Safety and reliability
A successful engine swap should be reliable, serviceable, and safe. Brakes, suspension, tires, fuel lines, wiring, mounts, and cooling should be appropriate for the increased power and intended use.
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Documentation
Engine swap articles should document donor vehicles, engine codes, transmission compatibility, required parts, wiring notes, mounts, known problems, and links to useful build threads or technical references.