Exhaust Service Tips
– Use “Wide-Band” style clamps instead of U-Bolt style clamps when installing replacement components. The resulting joint
will be leak-tight and more easily serviceable on future jobs. “Wide-Band” clamps provide the user full wrap-around
installation, no pipe distortion when sealing and minimizes exhaust leaks and eliminates the need for welding.
– Eliminate the exhaust system as a source of cab noise by isolating pipe and mufflers with exible hangers and brackets. On
installations where isolation mounts are not practical, use double wrapped mufers.
– Exhaust gases are passed through the mufer to reduce the noise of engine combustion. At the same time, back pressure
causes exhaust gases to remain in the engine cylinder after the exhaust stroke. And, while a certain amount of backpressure
is vital to optimal performance, too much can result in loss of horsepower and excessive engine/turbocharger operating
temperatures. When this occurs, performance and fuel economy can suffer.
– Remember to always replace components with like components in the exhaust system. By replacing an exhaust system part
with a like component, you can be assured of the most efficient performance on your engine.
– Contact our Customer Assistance team for any exhaust queries that you have
Reducing Noise Levels
There are five major sources that contribute to the noise level of a highway.
1. Fan Noise – Excessive fan speed is the biggest noise
source in this area. This can be controlled by the use of a
temperature-controlled or thermostatic fan. Other noise
concerns are bent fan blades and broken or missing
2. Air Intake – Both the type of system and the location of
the inlet affect the truck noise level. Air inlets that open to
the side are generally noisier than those that do not.
3. Mechanical Noise – The engine and drive train are the
major source of the noise. Operating speed, type of engine, and drive train all affect the total noise level. Shielding the
exposed areas with acoustic barriers will reduce noise
levels. Generally, any part of the engine or drive train that
can be seen while standing away from the truck will
contribute toward the total vehicle noise level.
4. Tyres – Many times this is the major noise source at high
speeds. The condition of the tyres and the tread pattern
affect the noise level. At low speeds, this is not a large
5. Exhaust System – Worn or inadequate exhaust systems
are the largest and the most frequent contributor to high
noise levels. A visual inspection and repair of leaking
connections or replacement of failed components will
noticeably reduce noise levels. If the noise level is still
too high, the addition of resonators, packed stacks, or a
change in mufers is recommended. The mufer
application and performance section of this catalog will
give you the recommended mufers for your particular
engine and system configuration.
SPECIFIC WAYS TO REDUCE EXHAUST NOISE LEVELS
1 . Worn or leaking exible tubing is a common noise source.
Replace the part if necessary. The service life of exible
tubing can be improved if it is installed in a relaxed
position. Bending, stretching and compressing all reduce
life because they limit the tubing’s ability to “flex”.
2. The entire exhaust system should be well supported. This
will reduce the noise generated by the exhaust pipes and
the mufer shell. Care must be taken to isolate engine
vibration from the exhaust system and to provide for
expansion when the system is hot.
3. The addition of an universal resonator in the system will
generally reduce the exhaust noise level from 3 to 6 dBA.
Packed stacks would reduce the noise level 3 to 4 dBA.
Both items have a minimal effect on engine backpressure.
4. Change from a single to a dual system. For maximum
benet, special “dual only” mufflers are usually
recommended. Lower system backpressure is generally
an additional benet of dual systems.
5. On horizontal systems, the tail spouts should be pointed
towards the center of the roadway. This reduces the noise
reected off the road surface and perceived by kerbside
observers to be quieter.
6. On vertical systems, straight stacks will yield lower sound
levels than will curved stacks. Straight stacks direct the
noise upward, where curved stacks direct noise towards