FiTech Fuel Injection Throttle Body Assembly

FiTech Throttle Body Assemblies: Modern EFI, Carburetor-Simple Installation

When a classic muscle car or hot rod builder decides it's finally time to ditch the carburetor, FiTech Fuel Injection is one of the first names that comes to mind — and their fuel injection throttle body assemblies are the centerpiece of that reputation. FiTech has built its identity around making the transition from carburetor to electronic fuel injection as painless as possible, and nowhere is that philosophy more evident than in their throttle body lineup.

Bolt-On EFI Without the Headaches

The defining advantage of a FiTech throttle body assembly is how naturally it integrates with existing engine hardware. FiTech's self-tuning throttle body systems bolt onto any 4-barrel intake manifold and require no laptop to set up. If your engine has a standard 4-barrel intake manifold, FiTech throttle body systems use a square bore 4150 flange pattern — the same as most 4-barrel carburetors — meaning the unit bolts directly into the same spot your carb once sat. That's a level of plug-and-play simplicity that sets FiTech apart from more complex EFI conversion approaches.

To further simplify wiring, FiTech's ECU is contained within the throttle body itself , eliminating the need to find a remote mounting location for a separate control unit. Once installed, the ECU reads data from the wideband O2 sensor, throttle position sensor, MAP sensor, and coolant temp sensor in real time, adjusting the fuel ratio and — on equipped systems — ignition timing to match engine speed and load.

Throttle Body Assembly Options for Every Build

FiTech offers throttle body assemblies across a wide power spectrum. Their throttle body EFI systems are rated from 400 to 1,200 HP , covering everything from mild street cruisers to high-output performance builds. For LS engine builders, FiTech throttle bodies provide high-flow performance, are built with cast aluminum construction, include the IAC motor, and are offered in low-profile designs in 92mm and 102mm diameters.

For classic builds requiring universal compatibility, the FiTech Universal 4150 Throttle Body features a 4150 flange designed to fit seamlessly on most intake manifolds, ensuring compatibility with a wide range of vehicles. The popular Go EFI 4 platform stands out as a full-featured option: rated at 600 HP with self-learning fuel and timing control and the ECU mounted right on the throttle body, it fits any 4-barrel intake manifold and works from street cruisers to bracket cars.

For high-performance applications demanding refined throttle response, the FiTech Nemesis Throttle Body EFI delivers exceptional performance and control, with a parabolic throttle design, inward-opening blades, and dual IAC motors that ensure optimal throttle response and precise idle control, even for large displacement engines.

Advanced Self-Tuning Technology

After inputting a few simple values — such as number of cylinders, displacement, type of cam, ignition type, and idle speed — FiTech's Advanced Self-Tuning feature makes any adjustments necessary as the vehicle is driven. All FiTech software also includes OBD-II diagnostic readouts and limp home modes, just like OEM ECUs — a reassuring level of sophistication for a system that installs in an afternoon. Backed by a 3-year limited warranty against defects in materials and workmanship under normal use and service , FiTech throttle body assemblies represent a compelling path to modern EFI performance.