For classic car enthusiasts, upgrading to electronic fuel injection (EFI) can significantly enhance performance, drivability, and fuel efficiency. The Triumph Stag, a British sports car from the 1970s, is often modified with modern technology to improve its original carbureted engine. One popular solution among restorers and tuners is the Fitech 39001, a self-tuning, two-barrel EFI system. This article provides a factual overview of the Fitech 39001 based on user experiences and technical descriptions, focusing on its compatibility with the Triumph Stag, installation considerations, and its self-tuning capabilities.
Overview of the Fitech 39001 EFI System
The Fitech 39001 is a modern electronic fuel injection system designed for easy integration into classic vehicles. It is a two-barrel (2BBL) system that combines a throttle body with a built-in electronic control unit (ECU). Unlike traditional carburetors or early EFI systems that require extensive tuning on a dynamometer, the Fitech 39001 features a self-tuning mechanism that adjusts air-fuel ratios in real-time based on feedback from a wideband lambda sensor. This eliminates the need for a rolling road session or manual tuning by a specialist.
The system is marketed as a "bolt-on-and-go" solution, meaning it can be installed with minimal modifications to the existing engine setup. According to a user who has successfully installed the Holley Sniper 2300 (a similar product from a competing brand), the Fitech 39001 is well-suited for use on the Triumph Stag engine. The user noted that a custom adapter was required to bolt the throttle body onto the Stag's intake manifold, which was 3D printed to ensure a proper fit.
Installation Considerations for the Fitech 39001
While the Fitech 39001 is marketed as a plug-and-play system, its installation on a classic vehicle like the Triumph Stag requires careful planning and attention to detail. The following considerations are based on the user's experience and the product's specifications as described in the source material.
1. Compatibility with the Triumph Stag
The Triumph Stag's original engine is a 3.0-liter inline-six, and the Fitech 39001 is designed to accommodate a wide range of engines, including inline-six configurations. The user who installed the similar Holley Sniper 2300 on a Stag engine reported no issues with power output or drivability after the modification. However, it is important to confirm that the Fitech 39001's throttle body dimensions and mounting points are compatible with the Stag's intake manifold.
In the user's case, a custom adapter was needed to fit the throttle body onto the manifold. This suggests that the Fitech 39001 may require a similar approach to ensure a secure and airtight connection. It is advisable to measure the intake manifold's dimensions and compare them with the throttle body's mounting specifications before purchasing or fabricating an adapter.
2. Electrical Integration
The Fitech 39001 is equipped with a built-in ECU that requires a stable power supply and proper grounding. The system must be connected to the vehicle's electrical system, including the ignition switch, alternator, and any necessary sensors. The user who installed the Holley Sniper 2300 reported that the system was easy to wire, but it is important to follow the manufacturer's wiring diagram to avoid potential electrical issues.
The system also relies on a wideband lambda sensor to monitor the air-fuel mixture and adjust fuel delivery accordingly. This sensor must be properly installed in the exhaust manifold to provide accurate feedback to the ECU. It is essential to use high-quality sensor wiring and ensure that all connections are insulated and protected from heat and vibration.
3. Fuel System Requirements
The Fitech 39001 requires a fuel pump capable of delivering a consistent flow of fuel at the correct pressure. The original Triumph Stag fuel pump is not designed for use with modern EFI systems, so it may be necessary to upgrade to an electric fuel pump with a pressure regulator. The user who installed the Holley Sniper 2300 reported using an electric pump to ensure proper fuel delivery and avoid issues with the original mechanical pump.
The fuel lines must also be inspected for leaks and replaced if necessary. A return-style fuel system is recommended to maintain stable fuel pressure and prevent fuel starvation under load. It is also important to install a fuel filter upstream of the throttle body to prevent debris from clogging the injectors.
4. Air Intake and Throttle Linkage
The Fitech 39001 features a throttle body with a built-in butterfly valve that must be connected to the vehicle's throttle linkage. The user who installed the Holley Sniper 2300 reported using a custom linkage setup to maintain smooth and responsive throttle operation. It is important to ensure that the throttle cable or pushrod is properly adjusted to prevent sticking or binding.
The air intake system should also be modified to accommodate the new throttle body. The original air filter and air box may need to be adapted or replaced to ensure proper airflow and avoid restrictions. A high-performance air filter may be beneficial to maximize airflow and improve engine efficiency.
Self-Tuning Features and Operation
One of the key advantages of the Fitech 39001 is its self-tuning capability. The system uses a wideband lambda sensor to continuously monitor the air-fuel mixture and make real-time adjustments to fuel delivery. This eliminates the need for manual tuning or a dyno session, making it ideal for DIY enthusiasts and restorers who may not have access to specialized equipment.
The self-tuning process works by analyzing engine load, RPM, and temperature data to determine the optimal air-fuel ratio for each operating condition. The ECU then adjusts the fuel injectors to maintain the desired mixture, ensuring smooth idle, responsive acceleration, and efficient fuel consumption. The user who installed the Holley Sniper 2300 reported that the system automatically adapted to different driving conditions without any intervention.
It is important to note that while the system is self-tuning, it may require some initial calibration to ensure accurate readings from the lambda sensor. The user should also monitor the system's performance over time and make any necessary adjustments to the sensor or ECU settings if issues arise.
Maintenance and Troubleshooting
Once installed, the Fitech 39001 requires minimal maintenance compared to traditional carburetors. However, it is important to periodically inspect the system for signs of wear or damage. The following are some common maintenance and troubleshooting steps based on the user's experience:
- Fuel Filter Replacement: Replace the fuel filter regularly to prevent debris from clogging the injectors. A clogged filter can lead to poor fuel delivery and engine performance issues.
- Sensor Inspection: Check the wideband lambda sensor for corrosion or damage. A faulty sensor can provide inaccurate readings, leading to improper fuel adjustments.
- Throttle Body Cleaning: Clean the throttle body and butterfly valve periodically to prevent carbon buildup, which can affect airflow and throttle response.
- ECU Firmware Updates: If the manufacturer releases firmware updates, consider installing them to improve system performance and stability.
If the user experiences issues such as rough idle, stalling, or poor fuel economy, it is advisable to check the system's wiring, fuel pressure, and sensor readings. A multimeter can be used to test the lambda sensor and ensure it is functioning correctly. If the problem persists, it may be necessary to consult a qualified technician or contact the manufacturer for further assistance.
Conclusion
The Fitech 39001 is a modern electronic fuel injection system that offers a reliable and efficient upgrade for classic vehicles like the Triumph Stag. Its self-tuning capabilities eliminate the need for manual adjustments, making it an attractive option for DIY enthusiasts and restorers. The system's compatibility with the Stag engine has been demonstrated by users who have successfully installed similar products, such as the Holley Sniper 2300.
Installation of the Fitech 39001 requires careful planning and attention to detail, including compatibility with the intake manifold, electrical integration, fuel system requirements, and throttle linkage. While the system is marketed as a "bolt-on-and-go" solution, it may require custom adapters or modifications to ensure a proper fit. The self-tuning feature ensures smooth operation and optimal performance without the need for a dyno session.
For users considering this upgrade, it is important to follow the manufacturer's instructions and seek professional assistance if needed. Regular maintenance and troubleshooting will help ensure the system continues to perform reliably over time.