With the complexity of factory OEM fuel injection systems, Techlusion felt it was important to give the motorsports owner/tuner a product that was easy to operate and understand while not upsetting the stock fuel curve or any of its functions. TFi box is just that product. By attaching itself to the injector trigger wires and controlling fuel delivery as the signal travels to each injector, the TFi box allows all the stock sensors and inputs to function just as the factory designed.

By looking at the fuel delivery to the engine by fuel injection as being fundamentally the same as that of carburetion, (because the engine only knows air/fuel ratio) the same basic principles would apply. Just as in the jet kit for carbureted engines, you would normally only change ranges of fuel; either the main jet, needle or idle mixture and the same should apply to fuel injection. The TFi box allows you to make low rpm/cruise fuel changes (needle) as well as high rpm/acceleration demands (main jet). As air and fuel is dynamic, meaning that it is always moving (a necessary function in the operation of a carburetor), the same principle can be applied to fuel injection. Except that now an electrical signal instead of vacuum and pressures delivers the fuel. Add to that thought, the understanding that an internal combustion engine operates best with different air/fuel ratios for cruising and light loads compared to hard acceleration and maximum rpm. It is important to give each range its own adjustment, just like a carburetor manufacturer has always used a needle & slide and a main jet to give both ranges independent ratio adjustments. Likewise the TFi box gives the same two adjustments with a simple turn of a screwdriver providing the same results we all came to understand in carburetor; needle and main jet changes.

Some additional features have been engineered into the TFi box to help both drivability and performance. First, the TFi box has an adjustable crossover setting that allows the owner/tuner to choose the base rpm that the TFi box switches from its light load /cruise mode into the high fuel range for performance. This adjustability allows both basic tuning and more sophisticated fine-tuning to adjust for specific racing situations. The crossover adjustment also has a load sensitive function that overrides the base rpm setting to allow an earlier crossover whenever large throttle openings are introduced at low rpm's. This feature equates to the function of a vacuum slide in a CV carb.

Another feature that is unique to the TFi box is a built in electronic accelerator pump. If, while operating in the light load/cruise mode, the TFi box detects a rapid opening of the throttle, a pre-determined amount of additional fuel is added to further increase throttle response and acceleration beyond what a factory fuel map will deliver.

Techlusion testing shows that in over 95% of applications, standard fuel or increases in fuel is what is required for performance tuning to compensate for emissions leanness causing poor throttle response, increased air flow by a less restrictive air filter or reduced back pressure created by freer flowing exhaust systems. In current fuel injection applications the likelihood of removing fuel from the stock ECU map is remote, as the fuel delivery is not affected by negative pressures caused by camshaft overlap, ram air, or induction tuning (areas in carburetion that require leaning out mixtures). Only modifications that cause decreases in the power curve will require detuning by removing fuel. So, for those reasons the function of the TFi box allows only for the addition of fuel to the fuel map. This makes the TFi box much more user friendly and a great value.

TFI Control Box Applications List