EXHAUST SYSTEMS, TURBROCHARGERS & SUPERCHARGERS

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EXHAUST SYSTEMS, TURBROCHARGERS & EXHAUST SYSTEMS, TURBROCHARGERS & SUPERCHARGERSSUPERCHARGERS

CHAPTER 28 – MODERN AUTOMOTIVE CHAPTER 28 – MODERN AUTOMOTIVE TECHNOLOGYTECHNOLOGY

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EXHAUST SYSTEMEXHAUST SYSTEM

Purpose:Purpose:Quiets engine operation and carries exhaust fumes Quiets engine operation and carries exhaust fumes

to the rear of the vehicleto the rear of the vehicle

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Typical Typical Parts:Parts:ExhaustExhaust manifoldmanifold

HeaderHeader pipepipe

Catalytic converterCatalytic converter

Intermediate pipeIntermediate pipe

MufflerMuffler

TailpipeTailpipe

HangersHangers

Heat shieldsHeat shields

Exhaust system clampsExhaust system clamps

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Typical Typical Parts:Parts:ExhaustExhaust manifoldmanifold

connects the cylinder head exhaust connects the cylinder head exhaust ports to header pipe.ports to header pipe.

HeaderHeader pipepipe

steel tubing that carries exhaust gases steel tubing that carries exhaust gases from the exhaust manifold to the catalytic from the exhaust manifold to the catalytic converter.converter.

Catalytic converterCatalytic converter

Device that removes pollutants from Device that removes pollutants from engine exhaust.engine exhaust.

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Typical Typical Parts:Parts:Intermediate pipeIntermediate pipe

Tubing sometimes used between the Tubing sometimes used between the header pipe and muffler or catalytic converter and header pipe and muffler or catalytic converter and mufflermuffler

MufflerMuffler

Metal chamber for damping pressure Metal chamber for damping pressure pulsations to reduce exhaust noisepulsations to reduce exhaust noise

TailpipeTailpipe

Tubing that carries exhaust from the Tubing that carries exhaust from the muffler to the rear of the car bodymuffler to the rear of the car body

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Typical Typical Parts:Parts:HangersHangers

Device for securing the exhaust system Device for securing the exhaust system to the underside of the car bodyto the underside of the car body

Heat shieldsHeat shields

metal plates that prevent exhaust heat metal plates that prevent exhaust heat from transferring into another objectfrom transferring into another object

Exhaust system clampsExhaust system clamps

U-bolts for connecting parts of the U-bolts for connecting parts of the exhaust system together.exhaust system together.

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Exhaust Back Pressure:Exhaust Back Pressure:

Pressure developed in the exhaust systemPressure developed in the exhaust system

Low Back Pressure Low Back Pressure = More efficient, well designed system= More efficient, well designed system

High Back PressureHigh Back Pressure = Reduction of engine power = Reduction of engine power

Factors that create/limit back pressure:Factors that create/limit back pressure:

Size of exhaust pipes, Catalytic converter, MufflerSize of exhaust pipes, Catalytic converter, Muffler

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Single vs. Dual Exhaust:Single vs. Dual Exhaust:

Single Exhaust SystemSingle Exhaust System

Most common – One pipe for exhaust gases to travel in from Most common – One pipe for exhaust gases to travel in from the engine to the rear of the vehicle. Used on small 4 cylinder and the engine to the rear of the vehicle. Used on small 4 cylinder and large V8 engineslarge V8 engines

Dual Exhaust SystemDual Exhaust System

Two separate pipes for exhaust gases to travel through Two separate pipes for exhaust gases to travel through reduced back pressure by letting the engine breathe better at high reduced back pressure by letting the engine breathe better at high RPM. Used on performance V6 and V8 enginesRPM. Used on performance V6 and V8 engines

Crossover PipeCrossover Pipe

connects the right & left header pipes to equalize back connects the right & left header pipes to equalize back pressure in a dual system to increase power.pressure in a dual system to increase power.

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Exhaust manifold heat valve: (heat control valve or heat riser)Exhaust manifold heat valve: (heat control valve or heat riser)

Forces hot exhaust gas to flow into the intake manifold to aid Forces hot exhaust gas to flow into the intake manifold to aid cold weather starting.cold weather starting.

Located in the outlet of the exhaust manifoldLocated in the outlet of the exhaust manifold

A heat sensitive spring or a vacuum diaphragm and A heat sensitive spring or a vacuum diaphragm and temperature sensing vacuum switch operate the butterfly valve.temperature sensing vacuum switch operate the butterfly valve.

Engine cold Engine cold – Valve closed increasing back pressure forcing – Valve closed increasing back pressure forcing hot gases into the exhaust passage of the intake manifold warming hot gases into the exhaust passage of the intake manifold warming the floor of the manifold to hasten fuel vaporization.the floor of the manifold to hasten fuel vaporization.

Engine warm Engine warm – valve open allowing gases to flow through – valve open allowing gases to flow through exhaust system normally.exhaust system normally.

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Exhaust system service: Exhaust system service:

Usually needed when a component in the system rusts and Usually needed when a component in the system rusts and begins to leak. begins to leak.

Engine combustions produces water and acids that Engine combustions produces water and acids that deteriorate the exhaust components. deteriorate the exhaust components.

Leaking exhaust systems can allow harmful fumes to enter the Leaking exhaust systems can allow harmful fumes to enter the passenger compartment.passenger compartment.

CARBON MONOXIDECARBON MONOXIDE

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Exhaust system repairs: Exhaust system repairs:

Faulty parts can be removed and replaced. Faulty parts can be removed and replaced.

Rust penetrant should be used on all fasters that are going to be Rust penetrant should be used on all fasters that are going to be re-used in order to remove them in the best condition as possible.re-used in order to remove them in the best condition as possible.

Removal of parts can be done with many tools:Removal of parts can be done with many tools:

Air ChiselAir Chisel Hand chisel / HammerHand chisel / Hammer

Cutting torchCutting torch HacksawHacksaw

Ratchet / Sockets (normally 14mm socket)Ratchet / Sockets (normally 14mm socket)

Exhaust pipe cutter (chain style)Exhaust pipe cutter (chain style)

Cut off tool (sawz-all)Cut off tool (sawz-all)

Always wear safety glasses to prevent rust and dirt from entering eyes.Always wear safety glasses to prevent rust and dirt from entering eyes.

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Exhaust system repairs: Exhaust system repairs:

Pipe expanders can be used on new pipe or old pipes to Pipe expanders can be used on new pipe or old pipes to make new parts fit better if needed.make new parts fit better if needed.

A pipe shaper can be used to straighten pipe ends that are A pipe shaper can be used to straighten pipe ends that are bent or dented. bent or dented.

Position all clamps properly making sure it is clamping both Position all clamps properly making sure it is clamping both pipes together (1/8” from end of outside pipe).pipes together (1/8” from end of outside pipe).

Install any necessary adapters, hangers.Install any necessary adapters, hangers.

Double check the system routing, does it have adequate Double check the system routing, does it have adequate clearance from the vehicles body and chassis?clearance from the vehicles body and chassis?

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Stainless Steel Exhaust system repairs: Stainless Steel Exhaust system repairs:

Use heavy duty clamps – regular clamps do not have enough Use heavy duty clamps – regular clamps do not have enough clamping force to properly seal stainless tubing. clamping force to properly seal stainless tubing.

When cutting stainless use the correct rod or wire material. When cutting stainless use the correct rod or wire material.

Stainless steel does not react the same as carbon steel when Stainless steel does not react the same as carbon steel when heated near its melting point. heated near its melting point.

Stainless can be “Stainless can be “RED HOTRED HOT” when it LOOKS COLD” when it LOOKS COLD

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Parts of the muffler: Parts of the muffler:

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TURBOCHARGERSTURBOCHARGERS

An exhaust driven fan or blower that forced air into the engine under An exhaust driven fan or blower that forced air into the engine under pressure. pressure.

Increase power outputIncrease power output

Can improve engine efficiencyCan improve engine efficiency

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Parts:Parts:

Turbine wheel Turbine wheel –– exhaust driven fan that turns the turbo shaft exhaust driven fan that turns the turbo shaft and compressor wheel.and compressor wheel.

Turbine housing Turbine housing –– outer enclosure that routes exhaust gases outer enclosure that routes exhaust gases around the turbine wheel.around the turbine wheel.

Turbo shaft Turbo shaft –– steel shaft that connects the turbine and steel shaft that connects the turbine and compressor wheels. It passes through the center of the bearing compressor wheels. It passes through the center of the bearing housing.housing.

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Parts:Parts:

Compressor wheel Compressor wheel –– driven fan that forces air into the engine driven fan that forces air into the engine intake manifold under pressureintake manifold under pressure

Compressor housing Compressor housing –– part of the turbo housing that part of the turbo housing that surrounds the compressor wheel. Its shape helps pump air into the surrounds the compressor wheel. Its shape helps pump air into the engine.engine.

Bearing housing Bearing housing –– enclosure around the turbo shaft that enclosure around the turbo shaft that contains bearings, seals, and oil passages. contains bearings, seals, and oil passages.

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Operation:Operation:

Exhaust gases expelled from engine Exhaust gases expelled from engine

enter the turbine housing, pass over enter the turbine housing, pass over

the turbine wheel and exit out the the turbine wheel and exit out the

exhaust system.exhaust system.

As the Engine RPM increases the turbine As the Engine RPM increases the turbine

spins faster. spins faster.

Turbine is connected to the compressor wheel by the turbo shaft Turbine is connected to the compressor wheel by the turbo shaft causing the compressor wheel to spin.causing the compressor wheel to spin.

As the compressor wheel spins it draws air into the compressor As the compressor wheel spins it draws air into the compressor housing. Centrifugal pressure causes the air to be thrown out of the housing. Centrifugal pressure causes the air to be thrown out of the turbo and into the engine under pressure.turbo and into the engine under pressure.

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Location:Location:

Usually on one side of the engine as close to manifold as possible to Usually on one side of the engine as close to manifold as possible to ensure gases are still expanding to help spin the turbine increasing ensure gases are still expanding to help spin the turbine increasing boost pressure and engine power. boost pressure and engine power.

Exhaust pipes connect manifold(s) to turbine housing. Header pipes Exhaust pipes connect manifold(s) to turbine housing. Header pipes connect to the exit of the turbine housing. connect to the exit of the turbine housing.

Blow through turbo system:Blow through turbo system:

Turbo located before the carburetor or throttle body, compressor Turbo located before the carburetor or throttle body, compressor wheel only compresses air, fuel enters after turbo.wheel only compresses air, fuel enters after turbo.

Draw-through turbo system:Draw-through turbo system:

Turbo located after carburetor or throttle body, compressor wheel Turbo located after carburetor or throttle body, compressor wheel draws in both air and fuel on carburetor and throttle body injection draws in both air and fuel on carburetor and throttle body injection systems. Port injection systems turbo will only pressurized air. systems. Port injection systems turbo will only pressurized air.

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Lubrication:Lubrication:

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Lubrication:Lubrication:

Needed to protect the turbo shaft and bearings from damageNeeded to protect the turbo shaft and bearings from damage

Turbochargers can operate at speeds of up to 100,000 RPM – Engine Turbochargers can operate at speeds of up to 100,000 RPM – Engine lubrication system must force engine oil into the turbo shaft bearingslubrication system must force engine oil into the turbo shaft bearings

Oil passages are provided in the turbo housing and bearings. An oil Oil passages are provided in the turbo housing and bearings. An oil supply line runs from the engine to the turbo. With the engine supply line runs from the engine to the turbo. With the engine running oil enters the turbo under pressure.running oil enters the turbo under pressure.

Sealing rings are placed around the turbo shaft at each end of the Sealing rings are placed around the turbo shaft at each end of the turbo housing to prevent oil leakage into the compressor and turbine turbo housing to prevent oil leakage into the compressor and turbine housings. housings.

A drain passage and drain line allow oil to return to the oil pan after A drain passage and drain line allow oil to return to the oil pan after passing through the turbo bearings.passing through the turbo bearings.

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Turbo Lag:Turbo Lag:

A short delay before the turbo develops sufficient boost (pressure A short delay before the turbo develops sufficient boost (pressure above atmospheric pressure) to meet engine demands.above atmospheric pressure) to meet engine demands.

As the driver presses on the accelerator pedal it takes a small As the driver presses on the accelerator pedal it takes a small amount of time before the engine creates enough exhaust gases to amount of time before the engine creates enough exhaust gases to spin the turbine and compressor wheels fast enough to develop spin the turbine and compressor wheels fast enough to develop boost.boost.

The vehicle may lack power for a second or two during Lag time.The vehicle may lack power for a second or two during Lag time.

Modern engines suffer from lag very little compared to older turbo Modern engines suffer from lag very little compared to older turbo designs as they are made with lighter materials that take less force to designs as they are made with lighter materials that take less force to spin. spin.

Carbon fiber enforced plastic impellers are used to cut weight and Carbon fiber enforced plastic impellers are used to cut weight and reduce lag. reduce lag.

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Intercoolers:Intercoolers:

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Intercoolers:Intercoolers:

An air-to-air heat exchanger that cools the air entering the engine.An air-to-air heat exchanger that cools the air entering the engine.

Radiator like device mounted at the pressure outlet of the turbo or Radiator like device mounted at the pressure outlet of the turbo or supercharger.supercharger.

When air is compressed its temperature rises, since hot air contains When air is compressed its temperature rises, since hot air contains less energy-providing oxygen by volume, it will produce less power. less energy-providing oxygen by volume, it will produce less power. A cooler charge of air is denser and can be mixed with more fuel to A cooler charge of air is denser and can be mixed with more fuel to increase combustion and engine power.increase combustion and engine power.

Outside air flows over and cools the fins and tubes of the intercooler Outside air flows over and cools the fins and tubes of the intercooler removing heat from the air inside the tubes. removing heat from the air inside the tubes.

Reducing air intake temperature increases power and reduces the Reducing air intake temperature increases power and reduces the tendency of detonation.tendency of detonation.

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Waste Gate:Waste Gate:

Limits the amount of boost pressure developed by the turbocharger.Limits the amount of boost pressure developed by the turbocharger.

A butterfly or poppet-type valve that allows exhaust to bypass the A butterfly or poppet-type valve that allows exhaust to bypass the turbine wheel.turbine wheel.

When air is compressed its temperature rises, since hot air contains When air is compressed its temperature rises, since hot air contains less energy-providing oxygen by volume, it will produce less power. less energy-providing oxygen by volume, it will produce less power. A cooler charge of air is denser and can be mixed with more fuel to A cooler charge of air is denser and can be mixed with more fuel to increase combustion and engine power.increase combustion and engine power.

Outside air flows over and cools the fins and tubes of the intercooler Outside air flows over and cools the fins and tubes of the intercooler removing heat from the air inside the tubes. removing heat from the air inside the tubes.

Reducing air intake temperature increases power and reduces the Reducing air intake temperature increases power and reduces the tendency of detonation.tendency of detonation.

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Limits the amount of boost pressure developed by the turbocharger.Limits the amount of boost pressure developed by the turbocharger.

A butterfly or poppet-type valve that allows exhaust to bypass the A butterfly or poppet-type valve that allows exhaust to bypass the turbine wheel.turbine wheel.

Without a waste gate the turbo could produce too much pressure in Without a waste gate the turbo could produce too much pressure in the combustion chambers. This could lead to detonation the combustion chambers. This could lead to detonation (spontaneous combustion) and engine damage.(spontaneous combustion) and engine damage.

A waste gate is a valve operated by a diaphragm assembly, intake A waste gate is a valve operated by a diaphragm assembly, intake manifold pressure acts on the diaphragm to control waste gate valve manifold pressure acts on the diaphragm to control waste gate valve action. The valve controls the opening and closing of a passage action. The valve controls the opening and closing of a passage around the turbine housing.around the turbine housing.

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Waste Gate Operation:Waste Gate Operation:

Under partial load the system routes all the exhaust gases through Under partial load the system routes all the exhaust gases through the turbine housing, the waste gate is closed by the diaphragm the turbine housing, the waste gate is closed by the diaphragm spring. This ensures there is adequate boost to increase engine spring. This ensures there is adequate boost to increase engine power.power.

Under full load, boost may become high enough to overcome the Under full load, boost may become high enough to overcome the diaphragm spring and opens the waste gate through the waste gate diaphragm spring and opens the waste gate through the waste gate passage and into the exhaust system. passage and into the exhaust system.

Less exhaust is left to spin the turbine. Less exhaust is left to spin the turbine.

Boost pressure is limited to a preset value. Boost pressure is limited to a preset value.

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Waste Gate Service:Waste Gate Service:

An inoperative waste gate can either cause too much or too little An inoperative waste gate can either cause too much or too little boost pressure.boost pressure.

If stuck open the engine will lack power.If stuck open the engine will lack power.

If stuck closed the engine may receive too much boost and If stuck closed the engine may receive too much boost and detonation and engine damage can occur.detonation and engine damage can occur.

Before replacing the waste gate, always check other parts:Before replacing the waste gate, always check other parts:

Knock sensorKnock sensor

Ignition timingIgnition timing

Vacuum pressure lines are all connectedVacuum pressure lines are all connected

Follow service manual instructions when testing or replacing a waste Follow service manual instructions when testing or replacing a waste gate. Waste gate removal is relatively easy, most are replaced rather gate. Waste gate removal is relatively easy, most are replaced rather than repaired.than repaired.

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Turbocharged engine modifications:Turbocharged engine modifications:

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Turbocharged engine modifications:Turbocharged engine modifications:

A turbocharged engine normally has several modifications to make it A turbocharged engine normally has several modifications to make it withstand the increase in horsepower.withstand the increase in horsepower.

•Lower compression ratioLower compression ratio•Stronger rods, pistons, and crankshaftStronger rods, pistons, and crankshaft•Higher volume oil pump and an oil coolerHigher volume oil pump and an oil cooler•Larger cooling system radiatorLarger cooling system radiator•O-ring type head gasketO-ring type head gasket•Heat resistant valvesHeat resistant valves•Knock sensor (ignition retard system)Knock sensor (ignition retard system)

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Turbo computer controls:Turbo computer controls:

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Turbo computer controls:Turbo computer controls:

The vehicle computer often controls the turbocharger by operating The vehicle computer often controls the turbocharger by operating the waste gate and by retarding the ignition timing when needed.the waste gate and by retarding the ignition timing when needed.

Several computer sensors are used to control the waste gate and Several computer sensors are used to control the waste gate and ignition timing:ignition timing:

•Manifold pressure sensor (boost pressure)Manifold pressure sensor (boost pressure)•Manifold air temperature sensorManifold air temperature sensor•Knock sensorKnock sensor•Throttle position sensorThrottle position sensor•Etc. Etc.

The computer uses preprogrammed data to determine if boost The computer uses preprogrammed data to determine if boost pressure or ignition timing should be altered in order to prevent pressure or ignition timing should be altered in order to prevent engine damage.engine damage.

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Knock Sensors:Knock Sensors:

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Knock Sensors:Knock Sensors:

Signals the engine control module if the engine begins to knock Signals the engine control module if the engine begins to knock (detonate or ping)(detonate or ping)

Mounted on the engine acting like a microphone if it hears a Mounted on the engine acting like a microphone if it hears a knocking sound it sends a signal to the computer which retards the knocking sound it sends a signal to the computer which retards the timing until the knock is gone. timing until the knock is gone.

Helps the engine control module keep the ignition timing advanced Helps the engine control module keep the ignition timing advanced as much as possible. This improves engine power and gas mileage. as much as possible. This improves engine power and gas mileage.

Protects the engine from detonation damage.Protects the engine from detonation damage.

One of the most important sensors in a computer controlled One of the most important sensors in a computer controlled turbocharger system. turbocharger system.

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Turbocharging system service:Turbocharging system service:

Problems usually show up as:Problems usually show up as:

•Inadequate boost pressure (lack of power)Inadequate boost pressure (lack of power)•Leaking shaft seals (oil consumption)Leaking shaft seals (oil consumption)•Damaged turbine or compressor wheels (vibration and noise)Damaged turbine or compressor wheels (vibration and noise)•Excess boost (detonation)Excess boost (detonation)

The best way to prevent damage in a turbocharged engine is to The best way to prevent damage in a turbocharged engine is to change the oil more frequently than normal (about every 3000 miles change the oil more frequently than normal (about every 3000 miles or 4827 km.)or 4827 km.)

The high rotating speeds of the turbo bearings and shafts are very The high rotating speeds of the turbo bearings and shafts are very sensitive to oil contaminants. The oil must be kept clean to ensure a sensitive to oil contaminants. The oil must be kept clean to ensure a long turbocharger life. long turbocharger life.

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Scanning a turbocharging system:Scanning a turbocharging system:

Scan tools can be used to check for Scan tools can be used to check for

trouble codes relating to the turbochargingtrouble codes relating to the turbocharging

system. system.

OBD II systems (1996 and newer) may show OBD II systems (1996 and newer) may show

codes for:codes for:

•Knock sensorsKnock sensors•Throttle position sensorsThrottle position sensors•Manifold pressure sensorsManifold pressure sensors•Manifold temperatures sensorsManifold temperatures sensors

Scan tools can sometimes be “confused” by mechanical problems Scan tools can sometimes be “confused” by mechanical problems within the engine. Ex. A piston pin knock could “fool” the knock within the engine. Ex. A piston pin knock could “fool” the knock sensor into thinking there is engine detonation and retard the timing.sensor into thinking there is engine detonation and retard the timing.

Keep this in mind when using scan tools.Keep this in mind when using scan tools.

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Checking a Turbocharging system:Checking a Turbocharging system:

There are several checks that can be made to determine There are several checks that can be made to determine turbocharging condition:turbocharging condition:

•Check connection of all vacuum lines to the waste gate and oil lines Check connection of all vacuum lines to the waste gate and oil lines to the turbocharger.to the turbocharger.

•Use a regulated low-pressure air hose to check for waste gate Use a regulated low-pressure air hose to check for waste gate diaphragm leakage and operationdiaphragm leakage and operation

•Use the dash gauge or a test gauge to measure boost pressure Use the dash gauge or a test gauge to measure boost pressure (pressure developed by the turbo under load. If needed connect the (pressure developed by the turbo under load. If needed connect the pressure gauge to an intake manifold fitting. Compare the gauge pressure gauge to an intake manifold fitting. Compare the gauge readings to specifications.readings to specifications.

•Use a stethoscope to listen for bad turbocharger bearings. Use a stethoscope to listen for bad turbocharger bearings.

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Checking a Turbocharger:Checking a Turbocharger:

To check the internal condition of a turbocharger, remove the unit To check the internal condition of a turbocharger, remove the unit from the engine.from the engine.

Unbolt the connections at the turbocharger, remove the oil lines and Unbolt the connections at the turbocharger, remove the oil lines and take the unit to your workbenchtake the unit to your workbench

Inspect the turbocharger wheels for physical damage.Inspect the turbocharger wheels for physical damage.

The slightest nick or dent will throw the unit out of balance, causing The slightest nick or dent will throw the unit out of balance, causing vibrationvibration

A dial indicator can be used to measure Axial and Radial play of the A dial indicator can be used to measure Axial and Radial play of the turbo shaft. (picture on next slide)turbo shaft. (picture on next slide)

Caution:Caution: never use a hard metal object or sandpaper to remove never use a hard metal object or sandpaper to remove carbon deposits from the turbine wheel. If you gouge the wheel, it carbon deposits from the turbine wheel. If you gouge the wheel, it can vibrate and destroy the turbo when it spins up to speed. can vibrate and destroy the turbo when it spins up to speed. Use a Use a soft wire brush and solvent to clean the turbo wheels.soft wire brush and solvent to clean the turbo wheels.

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Installing a new Turbocharger:Installing a new Turbocharger:

Most turbochargers are not repaired they are replaced with a new or Most turbochargers are not repaired they are replaced with a new or rebuilt unit. When installing a turbocharger you should:rebuilt unit. When installing a turbocharger you should:

•Make sure the new turbo is the correct type (compare part numbers)Make sure the new turbo is the correct type (compare part numbers)•Use new gaskets and sealsUse new gaskets and seals•Torque all fasteners to specificationsTorque all fasteners to specifications•Change the engine oil and flush the oil lines before starting the Change the engine oil and flush the oil lines before starting the engine. engine. •If the failure was oil related, If the failure was oil related,

check the oil supply pressure in the feed check the oil supply pressure in the feed

line to the turbocharger.line to the turbocharger.

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SUPERCHARGERSSUPERCHARGERS

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A compressor or blower driven by a belt, chain, or gearsA compressor or blower driven by a belt, chain, or gears

Unlike a turbocharger it is not driven by engine exhaust gases.Unlike a turbocharger it is not driven by engine exhaust gases.

Most passenger car superchargers are driven by a belt on the front of Most passenger car superchargers are driven by a belt on the front of the engine.the engine.

The belt drives the rotors inside the supercharger. As the rotors turn, The belt drives the rotors inside the supercharger. As the rotors turn, they compress the air inside the housing and force the air, under they compress the air inside the housing and force the air, under pressure into the engine intake manifoldpressure into the engine intake manifold

Supercharged engines provide added acceleration for entering Supercharged engines provide added acceleration for entering highway ramps and passing other vehicles.highway ramps and passing other vehicles.

The engine must be modified with a stronger reciprocating assembly The engine must be modified with a stronger reciprocating assembly (crankshaft, connecting rods and pistons) to withstand the power (crankshaft, connecting rods and pistons) to withstand the power increase without part failure. increase without part failure.

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An electromagnetic clutch is sometimes used to disengage the drive An electromagnetic clutch is sometimes used to disengage the drive belt from the blower. It works like an air-conditioning clutch to save belt from the blower. It works like an air-conditioning clutch to save energy when additional power is not needed.energy when additional power is not needed.

An intercooler is commonly used between the supercharger outlet An intercooler is commonly used between the supercharger outlet and the engine to cool the air and increase power (cooler air carries and the engine to cool the air and increase power (cooler air carries more oxygen needed for combustion).more oxygen needed for combustion).

Superchargers do not suffer from lag. A supercharger will instantly Superchargers do not suffer from lag. A supercharger will instantly produce boost because it is linked directly to the engines crankshaft.produce boost because it is linked directly to the engines crankshaft.

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Parts of the supercharger system:Parts of the supercharger system:

•TubingTubing•Air bypass valve inletAir bypass valve inlet•Adapter supercharger air outletAdapter supercharger air outlet•IntercoolerIntercooler•Adapter assembly air cooler Adapter assembly air cooler manifoldmanifold•Plenum assembly supercharger Plenum assembly supercharger inletinlet•SuperchargerSupercharger•Body assembly air intake charge Body assembly air intake charge throttlethrottle

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Supercharger types:Supercharger types:

Centrifugal superchargerCentrifugal supercharger

Rotor (Rootes) superchargerRotor (Rootes) supercharger

Vane superchargerVane supercharger

Note the differences in Note the differences in construction and operationconstruction and operation

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Supercharger service:Supercharger service:

A faulty supercharger will exhibit many of the same symptoms A faulty supercharger will exhibit many of the same symptoms described for a faulty turbocharger:described for a faulty turbocharger:

Lack of powerLack of power

Blue engine smokeBlue engine smoke

Abnormal noisesAbnormal noises

If the engine lacks power measure the boost pressure by connecting If the engine lacks power measure the boost pressure by connecting a pressure gauge to a fitting on the intake manifold.a pressure gauge to a fitting on the intake manifold.

If boost is low check the bypass actuator which controls the boost If boost is low check the bypass actuator which controls the boost pressure. (same idea as a waste gate on a turbocharged system)pressure. (same idea as a waste gate on a turbocharged system)

A bypass actuator that is stuck open will lower boost pressure and A bypass actuator that is stuck open will lower boost pressure and power. If it is stuck closed the boost will still not reach its maximum, power. If it is stuck closed the boost will still not reach its maximum, suspect internal rotor or housing wear in the superchargersuspect internal rotor or housing wear in the supercharger

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Supercharger service:Supercharger service:

Isolate noises using a stethoscope. Check for bearing noise at each Isolate noises using a stethoscope. Check for bearing noise at each end of the housing.end of the housing.

Internal noises usually require supercharger removal and rebuilding.Internal noises usually require supercharger removal and rebuilding.

A supercharger rebuild usually involves replacing all the bearings A supercharger rebuild usually involves replacing all the bearings and seals. You must measure rotor lobe and rotors and housing must and seals. You must measure rotor lobe and rotors and housing must be within specifications. be within specifications.

If parts are worn most shops install a new or rebuilt supercharger.If parts are worn most shops install a new or rebuilt supercharger.

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Scanning a supercharging service:Scanning a supercharging service:

A scan tool can be used to diagnose problems.A scan tool can be used to diagnose problems.

The scan tool will show electrical values and any diagnostic trouble The scan tool will show electrical values and any diagnostic trouble codes.codes.

You can check the operation of the knock sensor, manifold pressure You can check the operation of the knock sensor, manifold pressure sensor, and other devices that control supercharging.sensor, and other devices that control supercharging.

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EXHAUST SYSTEMS, TURBROCHARGERS & SUPERCHARGERS

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