... which might work for me anyway since I believe the aftermarket exhaust has basically run my mixture lean... but I do understand the argument.Overview
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.
Our 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.
My only problem with the PCIIIR is that I have to rely on the tuner who sets it up and downloads the correct map... (oh and the cost considering I went with a slip on to avoid having to remap...)2. I hear your product only adds fuel. Some people say you need to remove fuel?
That's correct in that our product only adds fuel. We designed it that way to keep it simple and affordable. It is our belief that in almost every situation, addition of fuel is what fuel injected bikes need. They are mapped by the factory to be lean in cruise and everyday driving conditions to meet emission standards and if you decide to change, most aftermarket exhaust systems tend to reduce back pressure which leans out the fuel even more. There are a few exceptions, one that comes to mind is the Honda CBR929/959, when the exhaust power valve is removed. Honda designed their engine specs around that feature, specifically the exhaust cam timing, and when you remove that valve, volumetric efficiency in the motor is lost and a bottom end bog occurs. You can mask that bog by pulling out fuel around that area, and for that, you may have to go to another product. But, our product performs well with all aftermarket exhausts keeping in mind that the exhaust must at least match the flow of the stock system you are removing (that volumetric efficiency thing again)
In short, yes.Originally posted by dj dunzie
ROB... what are your personal thoughts on trying out an aftermarket air filter first to see if it compensates a little for the increased flow through the exhaust? Waste of money that could have been spent on the PCIIIR?