Engine Management FAQ
Why do I need engine management? Consider your stock engine management for just a moment. Your stock engine control unit (ECU) is a very complex piece of circuitry that calculates hundreds of variables every second. All of these variables rely on inputs within a + or – range. When you modify your vehicle, these values change. As long as the changes are within the values the ECU expects to receive, your engine runs fine. Once the values are exceeded, the ECU is programmed to compensate to return the values to normal levels.
This is a layman’s explanation of how your stock ECU can actually work against you when modifying your vehicle. This also explains why modifications can feel great once they are bolted on but the butt dyno results seem to fade over time. This is due to ECU compensation.
What is the first step in finding what engine management I need? Finding a tuner. The Tuner FAQ will help with the general rules of finding a good tuner. Remember, it’s always better to have a custom tune vs. a plug and play or “staged” map. Always defer to the tuner’s advice as to what to choose as ultimately he will be the one to provide custom support. Discuss your goals and budget and your tuner should set you on the right path. If you are a “plug and play” kind of person, review the options below and decide for yourself along with input from locals in your regional forum and the car parts review forum.
What will engine management do for me? Generally speaking, engine management optimizes several engine functions to create more horsepower and efficiency. The stock ECU is designed to ensure your car runs fine and monitors the engine’s output parameters. Utilizing an aftermarket engine management solution takes this to the next level.
Often times, car manufacturers will program the stock ECU with a known amount of “play”. This amount of play allows the manufacturer an extra level of safety and/or the ability to utilize this at a later date so they can have an increase in HP in later years. An example of this is where a 2001 car has 200HP and a 2002 car has 215HP. Some manufacturers couple this with additional parts to get increased HP levels, but this should give you some idea of the concept. From a marketing and sales aspect, this ensures that the public will continually be interested in the new year models, even if the body style does not change. While this FAQ is not about the science and art of auto sales, this may give you an insight as to why the stock ECU is not 100% perfectly tuned from the factory.
The Vehicle Speed Sensor (VSS) is a small signal generator that is turned by a gear inside the transmission assembly. The Vehicle Speed Sensor produces 8 pulse per rotation which a stock computer assumes 8000 pulses per mile. The Vehicle Speed Sensor (VSS) is a variable reluctance sensor that generates a waveform with a frequency that is proportional to vehicle road speed. When the vehicle is moving slowly, the sensor produces a low frequency signal. As the vehicle speed increases, the sensor produces a higher frequency signal The Vehicle Speed Sensor (VSS) supplies this signal to the components that require vehicle speed information including the speed control amplifier for cruise control equipped vehicles and computer. The computer uses the VSS signal for emissions control programs and speed limiters. The emissions programing can cause a manual transmission vehicle to stall out while decelerating if no VSS is used.