Code of Federal Regulations Title 40. Protection of Environment § 40.91.311 Test conditions

(1) Ambient temperature levels encountered by the test engine throughout the test sequence may not be less than 20 °C nor more than 30 °C.

(2) Calculate all volumes and volumetric flow rates at standard conditions for temperature and pressure. Use these conditions consistently throughout all calculations. Standard conditions for temperature and pressure are 25 °C and 101.3 kPa.

(1) Naturally aspirated and mechanically supercharged engines:

(2) Turbocharged engine with or without cooling of inlet air:

(3) For a test to be recognized as valid, the parameter f must be between the limits as shown below:

0.96 < f < 1.04