Off the Shelf Performance Parts

Off the Shelf Performance Parts

Many, many aftermarket parts to choose Many, many aftermarket parts to choose fromfrom

Many are poorly designed and testedMany are poorly designed and tested Make an educated decisionMake an educated decision If it’s cheap, it’s probably because it’s cheapIf it’s cheap, it’s probably because it’s cheap Avoid products that use ‘buzzwords’ or slang Avoid products that use ‘buzzwords’ or slang

in place of technical terms.in place of technical terms. It is a ‘you get what you pay for’ world, but it It is a ‘you get what you pay for’ world, but it

can also sometimes be a ‘you paid too much can also sometimes be a ‘you paid too much for what you got’ world.for what you got’ world.

Remember to build your torque curve for Remember to build your torque curve for your application and choose parts that your application and choose parts that develop torque in the right area of the rev develop torque in the right area of the rev band.band.


IntakesIntakes Stock air box is there to muffle noise.Stock air box is there to muffle noise.

Inside airbox is a labyrinth used to cancel out noiseInside airbox is a labyrinth used to cancel out noise Stock intake is ‘Stock intake is ‘the other mufflerthe other muffler’’

Air does not like to turn corners, this makes the airbox Air does not like to turn corners, this makes the airbox restrictive especially restrictive especially at higher rpmat higher rpm..

Cold air intakesCold air intakes Air intake tube pulls air from outside the engine Air intake tube pulls air from outside the engine

compartmentcompartment Outside air is colder, and therefore more dense.Outside air is colder, and therefore more dense. Is usually a straight shot to the throttle body or Is usually a straight shot to the throttle body or

carburetor, no labrinth.carburetor, no labrinth. Flow better, provides additional horsepower at higher Flow better, provides additional horsepower at higher

rpm.rpm. At lower rpm, volume of airflow is less so power increase At lower rpm, volume of airflow is less so power increase

is less.is less. Cold air intakes can make engine sound much better.Cold air intakes can make engine sound much better.


IntakesIntakes Short Ram intakes Short Ram intakes ((

or just an air filter on carburetorsor just an air filter on carburetors)) Basically just a performance filter shoved onto the Basically just a performance filter shoved onto the

throttle body.throttle body. Sucks in all its air from under the hood.Sucks in all its air from under the hood. Air under the hood is hot, not conducive to good power.Air under the hood is hot, not conducive to good power. Airflow into engine compartment when vehicle is Airflow into engine compartment when vehicle is

moving is not enough to offset heat of engine.moving is not enough to offset heat of engine. On FI engines, as vehicle sits at stoplight ECU picks up On FI engines, as vehicle sits at stoplight ECU picks up

heat from IAT sensor. heat from IAT sensor. Mixture gets richerMixture gets richer Timing is retardedTiming is retarded When vehicle starts moving again, it takes a while for When vehicle starts moving again, it takes a while for

mixture and timing to improvemixture and timing to improve Falsely show power on the dyno, because hood is open.Falsely show power on the dyno, because hood is open.


Performance air filtersPerformance air filters Efficiency: How efficiently the filter can trap small particlesEfficiency: How efficiently the filter can trap small particles Capacity: How much dirt the filter can hold before it becomes Capacity: How much dirt the filter can hold before it becomes

restrictiverestrictive These definitions apply to all filters.These definitions apply to all filters. A standard A standard paper filter element paper filter element is most efficient at filtering dirtis most efficient at filtering dirt

Flows well when newFlows well when new Gets restrictive fasterGets restrictive faster Surface area is key to capacitySurface area is key to capacity The best choice for the streetThe best choice for the street

‘K and N’ type filters ‘K and N’ type filters flow very wellflow very well Not as efficient at removing dirt, K&N does not claim it does, advertiser Not as efficient at removing dirt, K&N does not claim it does, advertiser

do.do. Flow well when newFlow well when new Flow well when partially dirtyFlow well when partially dirty

This is the key advantage of this typeThis is the key advantage of this type Have high capacity.Have high capacity.

All filters are most efficient when dirtyAll filters are most efficient when dirty A clean air filter will not ‘protect your engine better’A clean air filter will not ‘protect your engine better’ As particles get trapped on top of each other they create smaller and As particles get trapped on top of each other they create smaller and

smaller poressmaller pores A dirty air filter will not reduce mileage on a modern fuel injected vehicleA dirty air filter will not reduce mileage on a modern fuel injected vehicle A dirty air filter can cause mixture to be rich on a carbureted engineA dirty air filter can cause mixture to be rich on a carbureted engine


Mass air flow meters Mass air flow meters (draw on board)(draw on board) MAF’s are tuned for emissions from the factoryMAF’s are tuned for emissions from the factory Real gains can be made at high RPMReal gains can be made at high RPM Bore is small to keep velocity high at low rpmBore is small to keep velocity high at low rpm

This makes readings accurate at low rpmThis makes readings accurate at low rpm MAF ‘MAF ‘elementelement’ (the actual measuring part) are ’ (the actual measuring part) are

usually replaceableusually replaceable Allows you to Allows you to replace with a larger housing replace with a larger housing without without

replacing elementreplacing element Mass air flow meters are taperedMass air flow meters are tapered

Increase velocity of air past the sensorIncrease velocity of air past the sensor Straight sensors can cause erratic readingsStraight sensors can cause erratic readings Straight housing causes surging or stalling at idleStraight housing causes surging or stalling at idle


Mass air flow metersMass air flow meters Takes reading ‘sample’ from center of boreTakes reading ‘sample’ from center of bore

Relocating sensor into a curve is a bad ideaRelocating sensor into a curve is a bad idea You may do this if installing a turbo kit, for exampleYou may do this if installing a turbo kit, for example

Air will get thrown to the outside of the pipe and not Air will get thrown to the outside of the pipe and not get measuredget measured

This causes inaccurate readings as the center of This causes inaccurate readings as the center of airflow changes at different loads and rpms.airflow changes at different loads and rpms.

Larger MAF requires recalibrationLarger MAF requires recalibration For same amount of voltage, MAF output voltage will For same amount of voltage, MAF output voltage will

be lowerbe lower Computer can not compensateComputer can not compensate Computer must be retuned to work with MAFComputer must be retuned to work with MAF (Draw voltage curve on board)(Draw voltage curve on board)


Throttle bodiesThrottle bodies Bore of throttle body can be made largerBore of throttle body can be made larger

Increases total flowIncreases total flow Power gains will show up at higher RPMPower gains will show up at higher RPM If increasing redline of engine will be neededIf increasing redline of engine will be needed May show improvements on stock engine because May show improvements on stock engine because

stock throttle body is tuned for idle/low speedstock throttle body is tuned for idle/low speed Will need to make new throttle platesWill need to make new throttle plates

Plate is not round, requires some math to determine Plate is not round, requires some math to determine proper size.proper size.

Electronic ‘fly-by-wire’ throttles may need to be Electronic ‘fly-by-wire’ throttles may need to be remapped for drivability (draw on board)remapped for drivability (draw on board)

Can make power more ‘linear’ (draw map on board)Can make power more ‘linear’ (draw map on board)


Intake manifolds (draw on board, label parts)Intake manifolds (draw on board, label parts) Larger (more volume in the runner, plenum) manifolds Larger (more volume in the runner, plenum) manifolds

make more powermake more power Short, fat runners for optimum high rpmShort, fat runners for optimum high rpm Long, narrow runner for optimum low rpmLong, narrow runner for optimum low rpm

Raise torque peak higher in the rpm bandRaise torque peak higher in the rpm band Velocity drops at lower rpm with large runners, this can Velocity drops at lower rpm with large runners, this can

be detrimental to low end torquebe detrimental to low end torque Aluminum manifolds can be ‘Extrude Honed’Aluminum manifolds can be ‘Extrude Honed’

Abrasive paste is forced through manifold to remove Abrasive paste is forced through manifold to remove material and polish walls of manifoldmaterial and polish walls of manifold

Follows existing contour.Follows existing contour. Fuel injection manifolds only have to flow airFuel injection manifolds only have to flow air

Fuel and air does not stay homogenous (well mixed) when Fuel and air does not stay homogenous (well mixed) when it has to turn cornersit has to turn corners

This is one of the main advantages of fuel injectionThis is one of the main advantages of fuel injection


Intake manifoldsIntake manifolds Carbureted manifolds for V8’sCarbureted manifolds for V8’s

Dual plane manifoldsDual plane manifolds Create peak torque in the lower RPM rangeCreate peak torque in the lower RPM range Best for street vehicles and trucksBest for street vehicles and trucks One side of carb feeds 4 cylinders, other side feeds One side of carb feeds 4 cylinders, other side feeds

other 4other 4 Creates smaller runners and plenum, more velocity Creates smaller runners and plenum, more velocity Image: Dual plane manifoldImage: Dual plane manifold

Single plane manifoldsSingle plane manifolds Create torque in higher RPM rangeCreate torque in higher RPM range Best for racing vehicles and lightweight vehiclesBest for racing vehicles and lightweight vehicles All 4 barrels of carburetor feeds all cylindersAll 4 barrels of carburetor feeds all cylinders Larger plenum and larger effective runnersLarger plenum and larger effective runners Image: Single plane manifoldImage: Single plane manifold


Intake manifoldsIntake manifolds Tunnel Ram Tunnel Ram

Not for street useNot for street use Uses large diameter, long runners to build Uses large diameter, long runners to build

velocity at high RPM.velocity at high RPM. Have poor drivability and torque at low RPMHave poor drivability and torque at low RPM Usually have two carburetorsUsually have two carburetors Good for raising impression ratio, your Good for raising impression ratio, your

friends will be impressedfriends will be impressed Image: Tunnel ram intakeImage: Tunnel ram intake


Intake manifoldsIntake manifolds Other available partsOther available parts

Intake trumpetsIntake trumpets Velocity stacksVelocity stacks


Cylinder headsCylinder heads Variety of aftermarket heads available for both domestic and Variety of aftermarket heads available for both domestic and

import enginesimport engines Can get aluminum heads for engine originally equipped with iron Can get aluminum heads for engine originally equipped with iron

heads, can use higher effective compression ratio = more power.heads, can use higher effective compression ratio = more power. Good heads are CNC ported. Hand ported heads can be Good heads are CNC ported. Hand ported heads can be

inconsistent from cylinder to cylinder. Some heads are ‘as cast’ inconsistent from cylinder to cylinder. Some heads are ‘as cast’ and can be hand polished = lower cost.and can be hand polished = lower cost.

Choose your heads before choosing camChoose your heads before choosing cam Have upgraded valves, retainers, keepers, springs, etc.Have upgraded valves, retainers, keepers, springs, etc. Using displacement ratio math, determine what volume (cubic Using displacement ratio math, determine what volume (cubic

centimeters or inches) combustion chamber you need to achieve centimeters or inches) combustion chamber you need to achieve your desired compression ratio.your desired compression ratio.

Get manufacturer supplied flow chart from flow bench to help Get manufacturer supplied flow chart from flow bench to help determine which cam you need.determine which cam you need.

Manufacturer should be able to help you determine what port Manufacturer should be able to help you determine what port volume you need to achieve your power goals.volume you need to achieve your power goals.

In general, smaller ports will develop torque in the lower rpm In general, smaller ports will develop torque in the lower rpm range and larger ports will develop torque higher in the rpm range and larger ports will develop torque higher in the rpm band.band.

Have upgraded valves, retainers, keepers, springs, etc.Have upgraded valves, retainers, keepers, springs, etc.


CamshaftsCamshafts There are way too many aftermarket camshafts on the market.There are way too many aftermarket camshafts on the market. Terms such as ‘stage 1’, ‘stage 2’, ‘tuner series’, ‘pro series’, Terms such as ‘stage 1’, ‘stage 2’, ‘tuner series’, ‘pro series’,

‘fast ramp’, ‘Xtreme’, ‘fireball’, ‘thumpr’, etc are all marketing ‘fast ramp’, ‘Xtreme’, ‘fireball’, ‘thumpr’, etc are all marketing buzzwords and are COMPLETELY USELESS.buzzwords and are COMPLETELY USELESS.

Many companies sell camshafts that were manufactured by Many companies sell camshafts that were manufactured by someone else, and put it a box with the companies name on it.someone else, and put it a box with the companies name on it.

A cylinder head flow chart is needed to properly choose the A cylinder head flow chart is needed to properly choose the lift of a camshaft.lift of a camshaft.

In general, the higher the engine revs, the more duration the In general, the higher the engine revs, the more duration the camshaft will need to have.camshaft will need to have.

Camshaft selection is extremely complicated.Camshaft selection is extremely complicated. It is best to let the experts give you advice, no one persons It is best to let the experts give you advice, no one persons

knows everything there is to know about engines.knows everything there is to know about engines. Don’t be afraid to get advice from more than one source.Don’t be afraid to get advice from more than one source. Camshafts have a bigger influence on power than anything Camshafts have a bigger influence on power than anything

else.else. Once a cam is broken in, it must not be separated from its Once a cam is broken in, it must not be separated from its

paired lifters.paired lifters. Always use new lifters on American V8’sAlways use new lifters on American V8’s


Exhaust manifolds/headersExhaust manifolds/headers Stock exhaust manifolds are made for emissions/costStock exhaust manifolds are made for emissions/cost Designed to keep heat in so they heat up the catalytic Designed to keep heat in so they heat up the catalytic

converter as fast as possible.converter as fast as possible. Often are very restrictive and a good way to ‘free up’ power.Often are very restrictive and a good way to ‘free up’ power. Newer vehicles have ‘pre-cats’ close to exhaust ports to ‘light Newer vehicles have ‘pre-cats’ close to exhaust ports to ‘light

off’ quicker.off’ quicker. ‘‘Headers’ are made of steel tubing and flow better than cast Headers’ are made of steel tubing and flow better than cast

iron manifolds.iron manifolds. Length and diameter of primary pipes, as well as header Length and diameter of primary pipes, as well as header

configuration determine rpm range.configuration determine rpm range. Tri-Y header – best for producing torque at a lower rpmTri-Y header – best for producing torque at a lower rpm 4 into 1 header – best for producing torque at higher rpm4 into 1 header – best for producing torque at higher rpm Has to do with timing of exhaust pulses. ‘Rarefraction’ timed to Has to do with timing of exhaust pulses. ‘Rarefraction’ timed to

help draw in air and fuel during valve overlap.help draw in air and fuel during valve overlap. Balance pipe – Used on V8 engines that do not have a flat Balance pipe – Used on V8 engines that do not have a flat

plane crank.plane crank. Dinan headersDinan headers Get A. Graham Bell’s book Get A. Graham Bell’s book Performance Tuning in Theory and Performance Tuning in Theory and

PracticePractice for good information on exhaust system design. for good information on exhaust system design.


MufflersMufflers High performance mufflers have less restriction.High performance mufflers have less restriction. Will make more power higher in the rpm band.Will make more power higher in the rpm band. Low rpm will see little gains unless there was a Low rpm will see little gains unless there was a

problem with the original design.problem with the original design. ‘‘Tunes’ the sound of the engine – like a musical Tunes’ the sound of the engine – like a musical

instrument.instrument. Universal performance mufflers may or may not Universal performance mufflers may or may not

work well on your car.work well on your car. Application specific mufflers are designed by trial Application specific mufflers are designed by trial

and error – tuned to what is most pleasing to the ear.and error – tuned to what is most pleasing to the ear. Helmholtz principal used on good mufflers (draw on Helmholtz principal used on good mufflers (draw on

board).board).


ElectronicsElectronics Power chipsPower chips

Make power by altering fuel and sparkMake power by altering fuel and spark Optimize for premium fuelOptimize for premium fuel

‘‘Software’Software’ Can be programmed through OBDII portCan be programmed through OBDII port Alters fuel, spark, cam phasing, fly-by-wire throttle, Alters fuel, spark, cam phasing, fly-by-wire throttle,

idle, rev limit, top speed, etc.idle, rev limit, top speed, etc. Plug and Play ECU’sPlug and Play ECU’s

Plug into existing wiring and allow tuneabilityPlug into existing wiring and allow tuneability Stand alone ECU’sStand alone ECU’s

Eliminate any emissions controls but allow ultimate Eliminate any emissions controls but allow ultimate in flexibility.in flexibility.

Off the Shelf Performance Parts

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