Intake, Exhaust systems and forced induction systems
Chapter 5 p201
Shop Manual

•	Nitrogen gas (N2) - Air is 78-percent nitrogen gas, and most of this passes right through the car engine. 
•	Carbon dioxide (CO2) - This is one product of combustion. The carbon in the fuel bonds with the oxygen in the air. 
•	Water vapor (H2O) - This is another product of combustion. The hydrogen in the fuel bonds with the oxygen in the air. 

•	Carbon monoxide (CO) - a poisonous gas that is colorless and odorless 
•	Hydrocarbons (HC) - produced mostly from unburned fuel that evaporates 
•	Nitrogen oxides (NO and NO2, together called NOx) - contributes to smog and acid rain, and also causes irritation to human mucus membranes

•	Sunlight breaks these down to form oxidants, which react with oxides of nitrogen to cause ground level ozone (O3), a major component of smog. 

Pollutants
•	Takes in - HC + O2 + N
•	Spits out - HC + O2 + CO + CO2 + NOx
•	High combustion temperature causes high NOx output
•	Restricted intake causes high CO (rich)
•	Unburned fuel HC
Catalytic Converter
(not Cadillac)
•	Chemically converts bad “gasses” into “good” gasses VIA a catalyst
•	Made of rare metals like Platinum, Rhodium, or Palladium
•	Honeycomb shaped chambers have gasses flow over the
•	Gets REALLY REALLY HOT!!!
•	CAT - AL - IT - ICK
Basic Types of converters
•	Two Way
–	Exhaust passes into two different types of material - HC and CO - Single Bed
•	Three Way
–	Exhaust passes into two different types of material, but may have plain old AIR added into the converter for better conversion - Helps keep NOx low as well as HC and CO - Dual Bed
–	p 139 classroom
Converters
•	Cannot use Regular (leaded fuel)
•	Pellet types are gone for good
•	Monolith types are today's design
•	Can malfunction and “melt”
–	Causes exhaust restrictions
–	Low power
–	High emissions
Testing CATs
•	Visual Inspection
•	Bluish Color = Overheated Cat
•	Missing Heat Shields
•	Physical Damage to Cat body

Testing...
•	Rattle Testing
•	Listen for broken substrate
•	Tap with rubber mallet for damaged heat shields of broken substrate

Testing
•	Back pressure testing
•	Install pressure tester into foreword O2 sensor mounting
•	Less then 1.25 PSI is desirable
•	Readings of over 2.00 PSI indicate a melted cat
Final Test
•	Temperature Testing
•	Warm vehicle up, run vehicle at 2000 RPM
•	Hold idle at 1500 RPM
•	Measure temperature difference at front and rear of converter
•	Temperature should be 100 Deg F or 8% hotter at the inlet then the outlet

Exhaust Manifolds
•	Direct “used” gasses out of engine
•	Made of cast iron or steel
•	Get VERY VERY HOT!
•	Header
–	Performance designed to “move” exhaust out of head - Steel tubes
•	Manifold
–	Directs Gases “gets the job done” - sharp angles - p208

Did it fail?
•	NEVER JUST REPLACE A CONVERTER WITHOUT FINDING THE TRUE NATURE OF THE PROBEM!
•	Often times a cat will last the lifetime of the car, the don’t “just wear out”
•	Running RICH is the #1 cause of cat failures!
Other steel parts under the car...
•	Exhaust pipes and hangers
•	Brackets and gaskets
•	Heat shielding
•	Muffler
•	Resonator (sound)
•	Tail Pipe
•	Clamps or Welds
•	p 219 - 221
Typical setup...
•	Exhaust manifold / Heat shielding
•	Intermediate pipe
•	Catalytic converter / Heat shielding
•	Pipe
•	Resonator
•	Pipe
•	Muffler
•	Tail pipe

Components...
•	Must not move too much under vehicle
•	Must have heat shielding if near floor or fuel tank
•	Must not rub under vehicle
•	Gaskets and Clamps must not leak
•	Holes and Coat Hangers are not cool!

Mufflers
•	Made of steel (stainless)
•	Has tubes or baffles that move exhaust pulses and deaden sound
•	Must provide SOME back pressure - this increases the volumetric efficacy of the engine - too much is bad, too little is bad also
•	Die after 4 or so years due to water and corrosive exhaust fumes

Repairs
•	“Muffler Tape”, crazy glue, $3 fixes   DO NOT WORK!
•	Replace damaged or rusted components
•	You get what you pay for
•	Beware of “lifetime” muffler deals

Testing...
•	Mufflers rot from the INSIDE out
•	Test for leaks by placing a wet rag over exhaust and listen for leaks
•	Signs of black soot at joints indicate leak spots
•	Make sure water outlet is clear
Lets take a look…

TURBOCHARGERS
•	Uses pressure from exhaust gasses to force more AIR into intake manifold
•	Has an axial shaft, one side is in the exhaust the other is in the intake
•	There is a turbine on both ends of the shaft
•	p223 Classroom
Turbochargers
•	Spin very VERY fast - 100,000 RPM!
•	Get very VERY hot
•	Force AIR into the intake, causes PRESSURE to BUILD in the intake - this is called BOOST PRESSURE
–	10 psi + 14.7 psi
•	Wastegate - A valve the dumps pressure in the intake
Turbo Design
•	Use air to cool the turbo
•	Turbo lag
•	Turbo heats air due to compression
–	May have an intercooler
•	The axial shaft MUST be lubricated
–	Oil
–	Antifreeze
–	Both
Turbo failures
•	Bearing failure of axial shaft
•	Oil / Coolant leaks
–	Internal
–	External
•	Piping leaks
•	Turbine Blades Damaged from mud or sand
•	Lack of maintenance - Wrong/Dirty oil

Superchargers
•	Mechanically driven by crankshaft VIA a belt
•	Same idea as a turbo - MORE AIR
•	No lag in power it = engine RPM
•	Requires stronger - block, heads, head bolts, crank, crank caps/bolts, timing chain, rocker arms, valves

Forced Induction Drawbacks
•	Cost!!!
•	Maintenance
•	MUCH higher engine temperatures
•	“Turbo lag”
•	Extra weight and more “stuff” under the hood
•	But hey…. Speed cost money.. How fast do you want to go?