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Vehicle Speed Parameters
Vehicle Speed Limit ( VSL)
OEM
Description:
Vehicle speed limiting sets the maximum speed of the
truck. Vehicle Speed Limiting cuts off the fuel to the
injectors when the truck exceeds the programmed
speed. With the release of NOV95 Personality Module
Software, VSL can be exceeded using cruise control
if the High Cruise Control (HCC) Set Limit parameter
is programmed higher than the Vehicle Speed Limit
parameter ( ).
MPH
R
P
M
VSL
Available:
All electronically controlled on-highway engines
covered in this handbook. The ability to program HCC Set
Limit above VSL is available on heavy duty engines only.
Range:
Engine
Range
Cat
Default
Minimum Maximum
3126E, C7, C9 GM
30 MPH
(48 km/h)
75 MPH
(121 km/h)
75 MPH
(121 km/h)
3126E, C7, C9
Other
30 MPH
(48 km/h)
127 MPH
(204 km/h)
127 MPH
(204 km/h)
C-10, C-12, C-15,
C-16, C11, C13,
C15
30 MPH
(48 km/h)
127 MPH
(204 km/h)
127 MPH
(204 km/h)
2007 C7, C9, C13,
C15
30 MPH
(48 km/h)
127 MPH
(204 km/h)
75 MPH
(121 km/h)
Advantages:
Using the VSL feature allows you to “gear fast - run
slow” to optimize the balance between fuel economy
and performance or simply specify for the best fuel
economy. Setting VSL allows the truck operator to
consistently operate the engine and truck at fuel
effi cient and safe vehicle speeds. Without VSL, most
trucks can be capable of very high vehicle speeds, due
to GFRS/GFRSS spec’ing methods.
Disadvantages:
VSL can be a hard limit that allows no fuel until the
vehicle slows to a speed below the programmed limit.
This makes the common practice of “running at hills”
very diffi cult. Soft VSL ( ) may alleviate this
problem if the driver expects to operate at or above VSL
on downhill runs.
See page 31
See page 31