Service Manual

ISB, ISBe and QSB (Common Rail [...] Engine Testing (Chassis Dynamometer)
Section 14 - Engine Testing - Group 14 Page 14-3
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Engine Testing (Chassis
Dynamometer) (014-002)
Setup
The performance of an engine installed in on-highway
vehicles can be tested on a chassis dynamometer.
NOTE: Because of driveline efficiency and engine-driven
accessories, the engine horsepower when measured at
the rear wheels will be reduced by approximately:
• 20 percent for single-axle vehicles
• 25 percent for tandem-axle vehicles
• 35 percent for recreational vehicles.
NOTE: These percentages are used for engine run-in
only and are not to be used as absolute figures.
WARNING
Follow all of the vehicle manufacturer's safety
precautions before installing or operating a vehicle on
a chassis dynamometer. Failure to do so can cause
damage to the vehicle and/or harm personnel.
CAUTION
Low-profile tires are more sensitive to heat than bias
ply tires. Excessive operating time at full load can
damage the tires due to overheating. Check the tire
manufacturer's recommendations for the maximum
allowable chassis dynamometer operating time.