Saab 900 1983 - Engine Oil; Oil Filter; Air Cleaner; Additional Information and Special Instructions - Turbo with APC System

ADDITIONAL INFORMATION AND
SPECIAL INSTRUCTIONS -
TURBO WITH APC SYSTEM
The turbo c harger is what really makes the Saab
Turbo special , being the component that
harnesses what is norma ll y wasted heat energy
in the exhaust.
It has a precision made and bal-
anced turbine wheel/compressor impeller as-
sembly capable of vibration free operation at
tens
of thousands of revolutions per minute.
The
impeller shaft bearing actually floats on a
thin film of engine oil circulated through the
turbocharger housing by the engine oil pump.
The
turbocharger will last the life of the car
provided
that it is not run without oil pressure at
the bearing,
the engine oil and filter change
requirements are
fulfilled , and no foreign ob-
jects pass through either the turb ine or com-
pressor side. The unit Is sealed and should
never be disassembled or cleaned internally .
The APC System detects the onset of engine
knock and adjusts the charging pressure of the
turbocharged engine accordingly. With the
engine thus protected from excessive and po-
tentially harmful knock, the compression ratio
was able to be increased to Improve overall fuel
efficiency . The APC System's capability to con-
stantly adjust maximum charging pressure for
variance
of fuel octane and engine operating
conditions allows optimum performance to be
obtained relative to the fuel quality chosen. Us-
ing 92 octane (pump rating) fuel, little or no
knocking 'o'!.ill be heard and maximum perfor-
mance will be available . On 87 octane , audible
knock will be present (but controlled) under
load and
performance will be somewhat re-
duced due to the APC System's effect upon the
maximum charging pressure.
A
control system, such as the APC System,
which is based upon a knock detector cannot
eliminate Individual occurrences of knocking
as these are necessary for the function of the
system. When the knock detector "hears"
engine knock the control unit lowers the charge
pressure in
stages to the point where knock
does not occur . If the same power demand
(throttle position) is maintained the APC Sys-
tem increases pressure until knock once again
occurs. The knock detector will again "hear"
the knock and the cycle will be repeated. The
System thereby
constantly searches for the op-
timum charge pressure for the combination of
eng.ine speed, load and knock level.
NOTEI It Is normal lor " pinging " or
knocking to occur In short bursts while
the engine Is operated under load, partl .
cularly on lower octane grades 01 luel .
When such knock Is heard you may ob ·
serve the needle of the Turbo pressure
gauge oscillating slightly, an Indication
that the APe System Is functioning.
Observe common sense do's and don'ts
when driving a Turbo!
STARTING-
Do idle the engine at least ten seconds after
start up to ensure full oil pressure at the turbo-
charger before engine speed Is increased, espe·
cially in colder weather .
Don't rev the engine immediately after starting
or permanent damage to the turbocharger will
result. To avoid possible engine damage, Don't
use full throttle while driving until a cold engine
has warmed up
for 2 to 3 minutes or until the
temperature gauge needle has entered the
green zone.
STOPPING-
Let the engine idle 20-30 se"onds before switch-
ing it off after driving to allow time for the turbo-
charger to coast down from high rpm before oil
pressure at the bearing is depleted . For the
same reason,
Don't rev the engine immediately
before switching it off. Permanent turbocharger
damage
will result. After hard driving let the
engine idle
about a minute to let the oil cool the
turbocharger bearing somewhat. This will also
help prevent breakdown of the oil.
Follow the recommended maintenance sched·
ule. In particular be sure to:
-Check the engine and transmission 011 levels
frequently .
-Change the engine oil and fliter at least every
5,000 miles or 6 months (more frequently un-
der severe driving conditions'). Use only oils
which meet specifications given in this man-
ual. Oil additives are not recommended.
-Have the valve clearances checked and , if
necessary, adjusted every 15,000 miles by a
qualified Saab technician.
-Follow the coolant recommendations (don 't
use plain water) and
change it regularly.
-Take your Turbo to a Saab dealer if you notice
a loss of power, an increase in oil consump -
tion, heavy engine detonation while acceler-
ating or driving at high speed, or abnormal
temperature or
boost indications. Do not run
the engine
without the standard air cleaner
and
exhaust system In place . Do not tamper
with the turbocharglng, APC oremission con-
trol systems .
• Severe driving conditions are those conditions
that may cause premature deterioration of the
oil through contamination or oxidation . See
Section IIA and Footnote 2 in the maintenance
schedule for detaiis.
21