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Cylinder Head Temperature
Cylinder head temperatures (CHT) usually run in the 300˚F to 475˚F range. The
best way to determine the correct temperature for your particular motor is to tune
for proper plug or piston color and then observe what the head temperature is for
various throttle settings and atmospheric conditions.
Temperatures consistently over 450˚F will damage the standard CHT sensor. If
your motor frequently runs at cylinder head temperatures over 450˚F, your
instrument should have an exhaust gas temperature function, which can use a
thermocouple CHT sensor. This sensor can be used without damage at higher
temperatures, but it is not as accurate as our standard CHT sensor.
Exhaust Gas Temperature
Exhaust gas temperature (EGT) is used primarily for adjusting the air/fuel ratio.
Because of its quick response, the effects of carburetor adjustments are seen
immediately. Fuel system and carburetor problems can often be spotted quickly
enough to prevent engine damage.
Exhaust gas temperatures typically run between 1100˚F and 1350˚F. The EGT on
a properly tuned engine will increase rapidly as the throttle is opened and as the
load on the engine is increased. At full throttle and full load the EGT will stabilize
at a temperature dependent on the air/fuel ratio. Both a “too lean” or a “too rich”
condition will be indicated by a lower than peak temperature. The “too lean”
condition can damage your engine. An increase in coolant temperature or cylinder
head temperature is usually an indication of this. The best way to determine what
temperature is normal for your motor is to tune for good plug or piston color and
then observe the temperature at various throttle settings.
Ignoring Multiple Beacons (Minimum Lap Time)
Setting a minimum lap time allows the instrument to ignore multiple beacons on
a track. After the minimum lap time has passed, the next beacon signal received
will trigger a new lap in the memory of the instrument. Minimum lap time is the
last number set in Set Limits. This is the time, in seconds, that the instrument will
ignore beacon signals after receiving a signal. Make sure this number is less time
than it takes to complete a lap, otherwise your instrument will record inaccurate
lap times.
