ing
single-engine
cUmb;
honrever,
during
multi-engine
climbs
at
higher
speeds
or
with closed
cowl
flaps, some
tlrottling may
be
required to
maintain
placarded
manifold
pressure.
When the
waste
gate
is
closed,
any change
in the turbocharger
speed
wiII
mean
a change ln engine
opera-
tion. Anything
that causes an increase
or
decrease
in turbine
speed
will
cause an increase
or
decrease in manifold
pressure.
U turbine speed in-
creases,
t}le manifold
pressure
increasesl
if the
turbine
speed
decreases,
the
manifotd
pressure
decreases. Any ehange
in
exhaust
flow
to
the
tur-
bine or
ram
induction air
pressure,
whether it is an increase or decrease,
will
be
magnified approximately I
to
10
times
by the compression
ratio
and the change
in
flow
through
the
exhaust
system.
TURBOCHARGED
ENGINE OPERATING
CH ARA
CT ERI STI
CS
,tTANIFOtD PRESSURE
VARIATION WITH ENGINE RP'IA
When
the
waste
gate
is open,
the
turbocharged engine
will
react the
sarne
as
a normally aspirated engine
when
the
engine
RPM
is
varied.
That is,
when
the
RPM
is increased,
the manifold
pressure
will deerease
slightly.
When
the engine
RPM
is
decreased,
the
manifold
pressure
will
inerease
slightly.
However, when
the
waste
gate
is closed,
manifold
pressure
variation
with
engine RPM
is
just
the opposite
of the
normally aspirated engine.
An
increase in
engine RPM will
result
in
an increase in manifold
pres-
sure,
and
a
decrease
in
engine
RPM
will
result
in
a
decrease
in
mani-
fotrd
pressure.
,ttANlFOtD
PRESSURE
VARIATION
WITH
AITITUDE
At
fulI
throttle
your
furbocharger is
capable
of
maintaining the maxi-
mum allowable
manifold
pressure
of
34. 5
inches Hg.
,
well
above
16,
000
feet. However, engine operating
limitations establish the mar<imum
mani-
fold
pressure
that
may be used.
From 16,000
feet
to higher
altitudes,
the
turbo
system automatically
reduces the
maximum manifold
pressure
you
will be able to obtain
to a ratio of
2.2
x
ambient
pressure;
however,
cruise
power
setting
must
be manually set.
2-36
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