Traxxas 49077-3 Owner's Manual page 12

THE TRX 3.3 RACING ENGINE
Dyno - Abbreviation for dynamometer. A precise piece of testing
equipment that accurately measures engine power and torque output
over the engine's entire rpm range.
EZ-Start - Traxxas on-board electric starting system. The system consists of
a hand held starter control unit and an on-board gearbox with an electric
motor to spin the engine.
Filter foam - The oiled foam element inside the air filter housing.
Fit - Usually refers to the fit of the piston and sleeve. If the fit is tight,
the piston will feel very tight at top of the sleeve (top dead center),
and the engine will have good sealing and compression. If the fit is
loose, compression will be low and both the piston and sleeve should
be replaced.
Flame-out - Occurs when the engine stops running at high rpm. Usually the
fault of an excessively lean fuel mixture or glow plug failure.
Fuel - (10%, 20%, 33%) The TRX 3.3 must have model engine fuel to run.
Traxxas Top Fuel is recommended. Fuel is sold in quarts and gallons from
™
hobby dealers. The 10%, 20% and 33% labeling refers to the percentage
of nitromethane contained in the fuel.
Fuel mixture - The ratio of fuel to air as determined by the needle settings
of the carburetor.
Fuel tubing (fuel line) - The thick silicone tubing that carries fuel from the
fuel tank to the carburetor.
Glow plug - The glow plug is located in the cylinder head at the top of the
combustion chamber. It contains an element that glows red hot when
voltage is applied. When the engine is being started, the heat from the
glow plug ignites the fuel mixture and starts the combustion process.
Glow plug driver - This tool clips onto the glow plug and supplies the
required voltage to light the glow plug element. It is also called an igniter.
EZ-Start equipped engines do not require this separate tool.
Header - The aluminum tube that connects the exhaust system to the
engine exhaust port. The length and diameter of the header must be
carefully selected to extract the most power from the engine.
High-speed needle (HSN) - Adjusts the carburetors fuel/air mixture at high
throttle openings.
Idle speed - The speed (rpm) the engine runs at when the transmitter's
throttle trigger is at neutral.
Idle speed screw (ISS) - Located on the carburetor body. This screw adjusts
the idle rpm of the engine.
Lean - A running condition where the engine is not getting enough fuel (for
the available air). Symptoms include engine overheating, or the engine
runs for a short time and then stalls, particularly at high speed. This is a
dangerous condition that should be corrected immediately or it can ruin
your engine.
Leaning the mixture - Turning either the high-speed and/or low-speed
needle(s) clockwise to decrease the amount of fuel the engine receives.
Low-speed needle (LSN) - Needle valve that controls the fuel mixture at
low throttle openings.
Needle valve - Valve consisting of a tapered needle that closes against a
corresponding seat to regulate fuel flow.
Nitro - Abbreviation for nitromethane, a component of model engine fuel
that improves fuel combustion and power output. Nitro also refers to a
class of R/C powered by model engines instead of electric.
Nitro content - The amount of nitromethane used in the fuel. Usually
measured as a percentage of the total fuel volume. Traxxas engines are
optimized to use 10-20% nitro. 33% nitro may be used for racing.
Nitromethane - Nitromethane is a component in the fuel that increases
power from the combustion process up to a point. Engines are generally
optimized to use a range of nitro content for the best power.
12 • T-MAXX 3.3 OWNER'S MANUAL
O-ring - Rubber "O"-shaped ring used as a sealing gasket.
Pipe - Abbreviation for the tuned exhaust pipe on a nitro engine. See
"Tuned Pipe".
Piston - The piston is the internal engine part that is attached to the upper
end of the connecting rod and moves up and down in the cylinder sleeve.
The precise fit between the piston and the sleeve creates a seal that
allows the engine to have the required compression for combustion.
Port - Ports are openings in the sleeve that allow atomized fuel to enter the
combustion chamber and burned exhaust gases to exit. The shape and
location of the ports are a large factor in controlling the engine timing
and power output.
Pre-filter - The outer air filter element in a two-stage air filter. This provides
the first level of air filtration for the engine. The majority of dirt and debris
will be stopped by this filter. Clean, re-oil, and replace this filter after every
hour of run time. Always use both the pre-filter and primary filter.
Primary filter - The inner air filter element in a two-stage air filter. This
provides a second level of air filtration after the pre-filter removes the
majority of dirt and debris. Clean, re-oil, and replace this filter after every
3 - 4 hours of run time. Always use both the pre-filter and primary filter.
Priming - Manually causing fuel to move from the fuel tank up to the
carburetor. This is sometimes necessary after the engine has been sitting
for a long period of time and all of the fuel has drained back to the tank.
On a Traxxas model this is done by holding your finger over the exhaust
tip for one or two seconds while the engine is starting.
Punch - A term that refers to how quickly the model responds to throttle
input or how quickly it accelerates.
Rich - A running condition where the engine is getting too much fuel for
the available air. It is better to run an engine slightly rich to increase
engine life. Excessively rich mixtures cause the engine to have sluggish
performance with exaggerated blue smoke and unburned fuel coming
from the exhaust.
rpm - Abbreviation for revolutions per minute (how many times the engine
crankshaft spins in a minute).
Sleeve - Internal engine part that contains the piston. The precise fit
between the sleeve and the piston creates a seal that allows engine
to have the required compression for combustion. The sleeve in a TRX
engine is made of brass and is then hard-chrome plated.
Slide carburetor - The throttle on a slide carburetor closes and opens by
sliding a barrel in and out of the carburetor body. This type of carburetor
is preferred for performance use because it provides a less restrictive
"straight-through" air path than the barrel carburetor design.
Stall - When the engine stops running, usually due to an incorrect fuel
mixture setting or running out of fuel.
TDC - Top dead center. The top-most position of the engine
piston stroke.
Tuned pipe - The tuned exhaust pipe usually consists of a specially-shaped
metal or composite chamber with baffles that is designed to enhance the
power output of the engine.
Two-stage air filter - An air filter with two separate, oiled foam filter
elements. The outer element, the pre-filter, removes the majority of dirt
and debris. The inner element, the primary filter, then filters the air again
before it enters the engine. The pre-filter should be cleaned, oiled, and
replaced every hour of runtime. The primary filter only requires cleaning
and re-oiling every 3 - 4 hours, depending on running conditions.
Wear-in - Fitment process that occurs during engine break-in where
internal engine parts develop an even more precise matched fit through
actual use under controlled circumstances.
WOT - Abbreviation for wide-open throttle.