Banks Power Cummins Motorhomes: (Diesel ’93 - 98 B5.9L & C8.3L) Power Systems- Stinger system 8.3L, 250-325-hp rated Class-A Pusher MH - Manual (Page 11)

IMPORTANT EMISSIONS INFORMATION
DIESEL SMOKE OPACITY TESTING
Several states are now imposing roadside inspections that
test diesel vehicles for smoke opacity (density) and issue
citations for excessively smokey vehicles. The predominate
standard is a 40% maximum opacity limit, with vehicles
exceeding this level either being fined or issued “fix-it”
tickets. A 40% opacity level means that 40% of the light
visible through the smoke as seen against a white
background is blocked by the smoke. Thus a clear exhaust
stream represents 0% opacity, while jet-black smoke
represents 100% opacity.
T h e o p a c i t y t e s t i s c o n d u c t e d w i t h o n e p e r s o n
depressing the accelerator pedal to the floor as quickly
as possible with the engine out of gear while another
person observes the opacity of the smoke. The engine is
held at full throttle for approximately two seconds, then
released. This is done 5-6 times, with the first 2-3 times
being considered invalid, as built up carbon being
blown out with the exhaust may show darker smoke.
T h e i n i t i a l b u r s t o f s m o ke f ro m t h e n ex t s eve ra l
accelerations is simultaneously compared with a tinted
p l a s t i c s a m p l e w h i l e v i ewe d a g a i n s t a w h i t e
background under daylight conditions. This is referred
to as a “snap idle” or “snap throttle” test and is often
conducted at roadside inspection sites or truck weigh
stations using a calibrated opacity meter placed over
the smoke stream. Although comparison testing with the
plastic sample will not give an actual opacity reading,
and it can be interpreted differently because of light
conditions and other variables, it will give you an
approximate indication of whether the vehicle’s smoke
opacity is below the 40% level.
Included with this Banks Stinger system is a 4-inch
square of acrylic plastic tinted to approximate a 40%
opacity. By using this plastic in the following procedure,
the vehicle’s smoke opacity can be compared to the
40% test level.
Start the vehicle and allow the engine to warm up.
You may want to drive the vehicle for 5-10 minutes
to speed up the process. Park the vehicle outside so the
tailpipe is not in shadow and the exhaust smoke can be
viewed against a white background that is not in shadow.
If a white background is not available, place a piece of
white cardboard, at least one-foot square, so the exhaust
smoke can be viewed in front of it.
With the vehicle running, set the transmission in Park
or Neutral, and apply the parking brake. Have
another person depress the accelerator pedal to the floor
as quickly as possible and hold it there for 2-3 seconds,
then release it. Repeat this procedure two more times.
Hold up the tinted plastic at arms length so it is
directly above the path of the exhaust smoke, so
both the smoke and the plastic can be viewed
simultaneously against the white background while
accelerating the vehicle. Have your helper repeat 2-3
more acceleration bursts while you observe the smoke and
plastic sample.
Compare the tint of the initial puff of smoke during
acceleration with the sample, after the initial puff the smoke
will most likely be lighter. The darkest par t of the
acceleration burst is the level measured in the test. It may
take several acceleration bursts for you to make a
determination of the vehicle’s opacity level.
If the smoke appears lighter than the sample, the
opacity is less than 40%. If the smoke appears
darker, the cam plate in the fuel injection pump may have
been mispositioned during installation. Please refer to page
8, INJECTION PUMP ADJUSTMENT, to verify that the
Banks Ottomind calibration cam is in the correct position.
This test assumes that the injection pump and fuel injection
system are adjusted properly and in good working order,
as other factors may affect the opacity level.
NOTE: In no case should this test be considered as meeting
any legal requirement where an actual opacity percentage
number is required. It is a “ball-park” approximation to
give the tuner a relative idea of where the vehicle’s opacity
level stands.
4.
3.
2.
1.
11 P.N. 96381