Stealth 2.0 Why our Throttle Controllers work. Most new cars are equipped with a drive-by-wire system. Throttle response can be negatively affected as drivers feel a noticeable delay when accelerating. This delay may be caused by faulty components, by design (lazy engine developers, decreasing emissions by not allowing an old engine design to do anything harsh), or by emission controls affecting the process. Before car emissions became a general health concern, carburetors had an "accelerating pump" which made the fuel mix richer when the accelerator pedal was depressed suddenly. The resulting hydrocarbon emissions from exhausts are a main reason that emission controls became mandatory, and most petrol-engined cars operate on average in stoichiometric mix mode. Some engine manufacturers are resigned to the fact and offer lackluster performance engines. R&D costs of engines that conform to emission legislation, while still offering desirable throttle response, is one of the many reasons why the number of engine manufacturers for personal cars has drastically shrunk in the past 30 years. On a closed drag strip or race track, a side by side comparison using the same vehicle, same driver, but one with a Stealth controller and one without a Stealth controllerwill result in a quicker time for the vehicle fitted with Stealth controller. When you open the throttle it responds by sucking in more air and adding more fuel. The power increase is caused because your RPM's rise. The faster your RPM's rise the faster your car can reach max power. The Stealth Throttle Controllers suit the full range of Toyota Vehicles that run a Electronic Throttle Control style throttle body.