Big Toe
To further explain what I am talking about in regards to simulated conditions, take the QSM11 spec sheet in this
LINK as an example. This is a standard spec sheet that Cummins will give to their customers (the vehicle manufacturers).
Notice at the top ,right below the emissions certification, where it states the simulated restrictions.
All data is based on the engine operating with fuel system, water pump, and 15 in H2O (3.733 kPa) inlet air restriction with 6 in (152mm) inner diameter, and with 2 in Hg (7 kPa) exhaust restriction with 5 in (127 mm) inner diameter; not included are alternator, fan, optional equipment and driven components. Coolant flows and heat rejection data based on coolants as 50% ethylene glycol/50% water. All data is subject to change without notice.And at the very bottom it states the certification standards along with what elevations these power numbers are good for before electronic derate is applied.
Curves shown above represent gross engine performance capabilities obtained and corrected in accordance with SAE J1995 conditions of 29.61 in Hg (100 kPa) barometric pressure (300ft (91m) altitude) 77 deg F (25 deg C) inlet air temperature, and 0.30 in Hg (1kPa) water vapor pressure with No. 2 diesel fuel. The engine may be operated up to 12,000 ft (3,658 m) altitude before electronic derate is applied.