Boost Limiter

Boost Limiter is calibration map in ECU that limits boost/MAP in order to avoid damage to turbocharger at various altitudes. Atmospheric pressure varies with altitudes - usual pressure at sea level is 1000hPa, highest mountain roads in European Alps 750hPa. Higher the altitude the less air density and higher probability of turbocharger overspeeding (resulting in damage or failure of turbocharger). Commonly used term in ECU calibration or so called chiptuning.