mapping the engine

[e_peña]

hey im a begginer and hope someone can help me.

i ve heard bout the throttle mapping or engine mapping and i know what it is (i think) but i dont totally understand if the mapping is a model that engenieers create to achieve a determined engine performance or is it just to see how the engine is working throughout the race? also aproxymately how many variables does it include? and what is or are the independent variables?

thanx for your help

[Rimrider]

Mapping is the calibration of fuel and spark for the engine with the engine management system.

The fuel and spark is determined for a given throttle opening (measured in degrees) and engine speed (rpm) and is entered into the 'map'. The map is divided up into a (normally) 16x16 grid. There will be 16 throttle positions and 16 rpm positions. Theres one grid for the fuel calibration (injector on time measured in milli-seconds) and another for the spark calibration ( measured in crankshaft degrees).

For example at 12,000rpm and 60 deg throttle the injector on time may be 6.5 m/secs and the spark may be 35 deg. This is entered into the 'maps'. The engine has to be run at all the parameters to find the calibration and this is known as 'mapping the engine'.

Other factors that influence the 'mapping' are air, water and fuel temperatures, barometric pressure, battery volts, air flow and exhaust temperature. How these influence the mapping is where it starts to get to complicated to explain here.

Rim