Modern cars are constantly being changed, mostly because of advancements in electronics. More and more vehicle systems that were previously mechanically controlled are now controlled by the vehicle's computer. One such new system is electronic throttle control, commonly known as drive-by-wire.
The drive-by-wire system eliminates the conventional mechanically operated system that had been used since the beginning of the automobile. The standard mechanically operated accelerator pedal uses a cable attached from the pedal to the throttle body. When your foot presses down on the pedal, the cable opens the throttle plate, allowing air to pass through into the engine. The engine RPM is directly proportional to the angle of the throttle plate, as shown below.
With drive-by-wire, the cable is replaced by an electronically controlled system using advanced electromechanical actuators, performance chips and highly accurate potentiometers. In place of a cable, an accelerator pedal position sensor is connected to the accelerator pedal. This sensor, which is a potentiometer, determines the position of the accelerator pedal and signals this information to the vehicle's computer, or ECM. The ECM, in turn, commands the throttle control motor to open or close the throttle valve. This system is shown in the accompanying schematic and explained in detail in the following video.
The drive-by-wire system has its limitations however, the main problem being that throttle response time is significantly slower. Throttle response, also known as a vehicle's responsiveness, is a measure of how fast an internal combustion engine can raise its power output from a low RPM to a higher more powerful RPM in response to a driver's request for acceleration; pushing the pedal down. Throttle response is often jumbled with better power; however throttle response is actually a measurement of the time taken for a change in power output.
As car guys, we all appreciate the need for speed and thrill of pushing our cars to newer limits, and slower throttle response will just increase the time it takes to get to your vehicle's max power. To address the problem the aftermarket world has developed a new system to override the factory electronic throttle control settings, which have a noticeable time delay. The Weapon-R I-Throttle Controller, is a great addition to add that extra "UMMPHH" to your drive-by-wire vehicle.
The I-throttle controller will basically bypass the computer in the vehicle. The controller is designed to take the information right from the accelerator pedal position sensor and compile it in a high speed controller circuit. It also slightly advances that number and then sends it directly to the computer through the OBDII port located under the driver's side knee bolster. By sending the information to the computer this way a couple of checks can be bypassed that the ECM (engine computer) will make before sending the signal to open the throttle plate. With this controller you have several different programming options; however the throttle response timing will be noticeably faster. Check out these two videos on the installation and programming and set up of the controller.
As you can see, connection and set up is a piece of cake. As long as your car is compatible it's a great addition to your new drive-by-wire vehicle, but is it safe? There are fail safes that are designed internally into your vehicle's computer system, that can detect any problems with this system and have the "ultimate power" to override everything and keep your car from accelerating wildly out of control. So the question is; are you going to wait for power, or are you going to demand it right now?