What is the purpose of Engine Management Systems?
A modern engine has to fulfill a diverse set of requirements ranging from cold-start to
strict exhaust emission control.  We also expect our vehicles to be fun to drive and
deliver consistent performance in a variety of conditions.  Electronic engine management
systems meet these requirements by maintaining proper air-fuel mixture, controlling
spark ignition and turbo boost.  In the end, these electronic devices allow our vehicles
to achieve maximum performance, while still maintaining fuel economy and controlled
exhaust emissions.

What are the main objectives of an Engine Management System?
Lambda Regulation (for gasoline engines) - The throttle or "gas-pedal" controls the
amount of air an engine takes in. A key objective of the ECU is to mix fuel with the
incoming air at the proper ratio (By mass, 14.7 parts of air to 1 part of fuel).
At the ideal air-fuel mixture lambda = 1.  This stoichiometric ratio is the best
compromise between power, fuel consumption, and exhaust gas emissions.
When there is excess air, lambda > 1, when there is excess fuel, lambda < 1.
A lambda sensor or oxygen sensor, installed in the exhaust manifold,  provides
feedback to the ECU and indicates whether the air-fuel ratio needs to be adjusted.

Ignition Timing
The moment that the spark plug fires is controlled by the ECU and is dependant
upon engine rpm, engine load, temperature, altitude, and feedback from the
knock sensor.  In Motronic systems the ECU refers to a timing map which is a
set of data points in the ECU's EPROM which gives the best timing point for all
conditions.

Knock Regulation
Economical fuel consumption and high torque can be achieved by higher
compression ratios in the engine.  Increased compression ratios, especially as a
result of turbocharging, can lead to pre-ignition of the air-fuel mixture. A knock s
ensor can be used to control ignition timing to prevent knock from damaging the
engine.  If the knock sensor detect pre-ignition the ignition timing can be retarded
to prevent pre-ignition and then slowly advanced back to the original value.
In turbocharged vehicles, the knock sensor can also be combined with boost
control to cut back boost pressure if the knocking persists and then slowly restore
boost.  Knock control allows more turbo boost and higher compression ratios for
more power while still protecting the engine from knock damage.  The octane r
ating of gasoline at the pump is a measure of the fuel's ability to resist pre-ignition.
When high octane fuel is used in a vehicle with knock control the engine can adapt
to the improved fuel quality and deliver more power.

Turbo Boost Control
Turbo boost control systems serve to limit the boost pressure from destroying the
engine, to keep the turbocharger from destroying itself, and to control the boost
characteristics to achieve the desired engine performance.   Modern boost control
system utilize a wastegate frequency valve that serves to control the wastegate
operation, which in turn, limits turbo boost.  The frequency valve is controlled by
the ECU  and is therefore integrated into the engine management system.

Idle Control
Smooth idle, in both cold-start and warm engine conditions, and good off-idle throttle
response are important aspects of engine control that contribute to overall powertrain
performance. During cold-idle, more air and fuel are needed to overcome the higher
running friction of a cold engine. The cold-idle speed is also raised by the ECU to
prevent engine stall and maintain off-idle throttle response
 

What do we change when we chip-tune your vehicle?
Fuel delivery, ignition timing, and boost control during off-idle throttle conditions are
the main parameters modified to increase the performance of your vehicle. A series
of engine control maps reside on the ECU's EPROM which control these parameters.
Through extensive testing, the manufacturer develops the data points on the maps for
overall fuel economy, emissions limits, operating robustness, and desired engine
performance.   When we chip-tune your vehicle we alter these maps to shift the overall
vehicle compromise with a bias towards performance.  Through dynamometer testing
we optimize the data maps to deliver optimal horsepower and torque in order to deliver
a superior driving experience for your vehicle.