J.P. Instruments EDM 740 Pilots Guide - Manual (Page 7)

For Your Safe Flight Page 7
The following depicts the power, mixture and temperature relationships.
E
G
T
°F
b
e
lo
w
p
e
a
k
P
e
rc
e
n
t
o
f
b
e
s
t
p
o
w
e
r
C
H
T
°F
c
h
a
n
g
e
fr
o
m
b
e
s
t
p
o
w
e
r
Best
power
range
0
-
100
-
50
-
20
20
-
60
-
40
0
-
80
10
0
8
5
9
0
9
5
8
0
Perc
ent
pow
er
Sp
ecif
ic
fue
l
co
nsu
m
ptio
n
Too
lean
Lean Rich
Full Rich
(Take-off)
EG
T
CH
T
First cylinder to
peak. Use for ROP
Rich of Peak
leaning
Last cylinder to
peak. Use for LOP
Lean of Peak
leaning
Peak Power
Best
economy
range
GAMI
spread
As the mixture is leaned, EGT rises to a peak temperature, and then
drops as the mixture is further leaned. Peak power occurs at a mixture
using more fuel than at peak EGT. Best economy occurs at peak EGT.
Accurate leaning yields optimal engine temperatures. By being able to
precisely adjust the mixture, your engine can produce either the best fuel
economy or maximum power, whichever you choose.
A single EGT gauge merely gives you an average of a few cylinder’s
temperature: some cylinders can be too rich, while others too lean.
Variations produced by differences in fuel distribution, ignition, and
compression will cause each cylinder to peak at a different temperature.
In some cases the coldest cylinder will peak first. TIT will run up to 100
degrees hotter than the hottest EGT.