Review of HP and Torque Torque is a measurement of twisting force. Torque is a measurement of...

Review of HP and TorqueReview of HP and Torque Torque is a measurement of twisting force.Torque is a measurement of twisting force. A 1 foot wrench with 1 pound of force A 1 foot wrench with 1 pound of force

pushing on the end of the wrench is said to pushing on the end of the wrench is said to produce 1 foot-pounds of torque.produce 1 foot-pounds of torque.

There does not need to be motion to create There does not need to be motion to create torque, unlike horsepower.torque, unlike horsepower.

Torque is a SCALAR measurement, which Torque is a SCALAR measurement, which means it has magnitude only.means it has magnitude only.

Electric motors can produce torque at zero Electric motors can produce torque at zero rpm.rpm. Engines can’t because they won’t run at low rpm.Engines can’t because they won’t run at low rpm.

Review of HP and TorqueReview of HP and Torque

Horsepower is a measure of work.Horsepower is a measure of work. Horsepower can only be calculated after Horsepower can only be calculated after

torque and rpm are known.torque and rpm are known. Horsepower is a VECTOR measurement, Horsepower is a VECTOR measurement,

meaning that it has both magnitude and meaning that it has both magnitude and direction.direction. Direction in this case is rotary.Direction in this case is rotary. If there is no motion, no work is done.If there is no motion, no work is done.

Because of this, the engine must be Because of this, the engine must be rotating to create horsepower.rotating to create horsepower.

Review of HP and TorqueReview of HP and Torque

Can be thought of as weight lifters.Can be thought of as weight lifters. ‘‘A weightlifter can lift 400 lbs’A weightlifter can lift 400 lbs’

All this tells us is that he can lift 400 lbs.All this tells us is that he can lift 400 lbs. We don’t know how many times per minute he We don’t know how many times per minute he

can lift this much.can lift this much. We can compare this to TORQUE.We can compare this to TORQUE.

‘‘A weightlifter can lift 400 lbs 5 times per A weightlifter can lift 400 lbs 5 times per minute’minute’ Not only does this tell us how much he can lift but Not only does this tell us how much he can lift but

how much per minute.how much per minute. We can compare this to horsepower.We can compare this to horsepower.

DynamometersDynamometers What is a dynamometer?What is a dynamometer? On the most basic level, a On the most basic level, a dynamometer is a tool for measuring dynamometer is a tool for measuring the torque output and rpm of an the torque output and rpm of an engine.engine. Using the torque measurement and Using the torque measurement and rpm the dynamometer will rpm the dynamometer will automatically calculate horsepower.automatically calculate horsepower. Horsepower is not directly Horsepower is not directly measurable.measurable. Horsepower = Torque x RPM / 5250Horsepower = Torque x RPM / 5250

DynamometersDynamometers Today’s dynamometers take a variety of Today’s dynamometers take a variety of

measurements.measurements. Air/fuel ratio (AFR).Air/fuel ratio (AFR). Air/fuel ratio is measured using a device Air/fuel ratio is measured using a device

calling an air/fuel ratio analyzer.calling an air/fuel ratio analyzer. A popular AFR analyzer is MoTeC’s A popular AFR analyzer is MoTeC’s PLMPLM.. High end units are made by High end units are made by HoribaHoriba or or

LabcellLabcell.. Hobby level kits are made by various Hobby level kits are made by various

manufacturers and are available by manufacturers and are available by companies such as Summit Racing.companies such as Summit Racing.

DynamometersDynamometers

The air/fuel ratio analyzer has a sensor, The air/fuel ratio analyzer has a sensor, similar to an O2 sensor, which is bolted similar to an O2 sensor, which is bolted into the exhaust using a ‘bung’.into the exhaust using a ‘bung’.

The sensor is called a UEGO (universal The sensor is called a UEGO (universal exhaust gas oxygen) sensor.exhaust gas oxygen) sensor.

Also known as a ‘Lambda’ sensor.Also known as a ‘Lambda’ sensor. It is not the same as an oxygen sensor It is not the same as an oxygen sensor

or air/fuel ratio sensor found in a or air/fuel ratio sensor found in a normal passenger car or truck.normal passenger car or truck.


The high end air/fuel ratio analyzers The high end air/fuel ratio analyzers use a sensor which is very accurate use a sensor which is very accurate and has a very high sampling rate.and has a very high sampling rate.

The ‘sampling rate’ is the speed at The ‘sampling rate’ is the speed at which the measurements are updated.which the measurements are updated.

Air/fuel ratio is defined as the ratio, Air/fuel ratio is defined as the ratio, by weight, of air to fuel.by weight, of air to fuel.

The stoichiometric ratio, also known The stoichiometric ratio, also known as ‘stoich’, is 14.7:1 for gasoline.as ‘stoich’, is 14.7:1 for gasoline.


The stoichiometric ratio is that ratio The stoichiometric ratio is that ratio at which every molecule of air will at which every molecule of air will chemically react with every molecule chemically react with every molecule of fuel.of fuel.

In practice, this never happens – In practice, this never happens – there are always molecules that do there are always molecules that do not react and leave via the tailpipe.not react and leave via the tailpipe.

A 14.7:1 AFR would be 14.7 lbs of A 14.7:1 AFR would be 14.7 lbs of air to 1 pound of fuel.air to 1 pound of fuel.


An AFR less than 14.7:1 is considered An AFR less than 14.7:1 is considered ‘rich’.‘rich’.

This means that there is more fuel in the This means that there is more fuel in the mixture than is chemically correct.mixture than is chemically correct.

For example, 12.5:1 AFR.For example, 12.5:1 AFR. An AFR more than 14.7:1 is considered An AFR more than 14.7:1 is considered

‘lean’.‘lean’. This means that there is less fuel in the This means that there is less fuel in the

mixture than is chemically correct.mixture than is chemically correct. For example, 16:1 AFR.For example, 16:1 AFR.

DynomometersDynomometers

Some tuners prefer to tune in ‘Lambda’.Some tuners prefer to tune in ‘Lambda’. Also known as the ‘excess air factor’.Also known as the ‘excess air factor’. In Lambda, stoich is represented by ‘1’.In Lambda, stoich is represented by ‘1’. Anything less than 1 is rich.Anything less than 1 is rich. For example, .85 Lambda corresponds to For example, .85 Lambda corresponds to

a 12.5:1 AFRa 12.5:1 AFR A 1.1 Lambda corresponds to a 16:1 A 1.1 Lambda corresponds to a 16:1

AFR.AFR.


Coolant temperature.Coolant temperature. It is very important that the engine It is very important that the engine

coolant temperature be consistent from coolant temperature be consistent from one dyno ‘pull’ to the next or readings one dyno ‘pull’ to the next or readings could be inaccurate.could be inaccurate.

Exhaust temperature (using Exhaust temperature (using thermocouples).thermocouples).

A thermocouple is a device which plugs A thermocouple is a device which plugs into each individual exhaust port and into each individual exhaust port and measures temperature.measures temperature.


By probing individual exhaust ports you can By probing individual exhaust ports you can determine if there is a problem in one determine if there is a problem in one cylinder. Or, on a carbureted engine, you cylinder. Or, on a carbureted engine, you can determine if equal amounts of fuel and can determine if equal amounts of fuel and air is being delivery to each cylinder.air is being delivery to each cylinder.

Lean cylinders will have higher temperatures Lean cylinders will have higher temperatures that rich cylinders.that rich cylinders.

The extra fuel in a rich mixture causes The extra fuel in a rich mixture causes combustion to be cooler due to a phenomena combustion to be cooler due to a phenomena called ‘latent heat of vaporization’.called ‘latent heat of vaporization’.


Brake specific fuel consumption Brake specific fuel consumption (BSFC).(BSFC).

BSFC is a measure of fuel efficiency.BSFC is a measure of fuel efficiency. BSFC is the rate of fuel consumed BSFC is the rate of fuel consumed

divided by the power produced.divided by the power produced. BSFC is expressed in ‘pounds per BSFC is expressed in ‘pounds per

horsepower hour’ or lbs per hp/hr.horsepower hour’ or lbs per hp/hr.

DynamometersDynamometers An efficient engine might be around .35 lbs An efficient engine might be around .35 lbs

per hp/hr.per hp/hr. An inefficient engine might be around .60 An inefficient engine might be around .60

lbs per hp/hr.lbs per hp/hr. It is possible that both these engine make It is possible that both these engine make

the same amount of horsepower.the same amount of horsepower. The engine with .35 lbs. per hp/hr would The engine with .35 lbs. per hp/hr would

get considerably better fuel consumption.get considerably better fuel consumption. Fuel efficiency very important in endurance Fuel efficiency very important in endurance

racing (races lasting a long time – 4, 12, or racing (races lasting a long time – 4, 12, or 24 hours) for less pit stops.24 hours) for less pit stops.


Intake air temperature.Intake air temperature. The temperature of the air coming The temperature of the air coming

into the engine.into the engine. Air temperature has a very large Air temperature has a very large

effect on power output.effect on power output. Colder air = more power.Colder air = more power. Cold air is more dense and therefore Cold air is more dense and therefore

contains more oxygen per unit contains more oxygen per unit volume.volume.


Ignition timing and advance curves.Ignition timing and advance curves. Some dynamometers can track Some dynamometers can track

ignition timing advance.ignition timing advance. Some dynamometers have Some dynamometers have

integrated detonation detection integrated detonation detection equipment.equipment.


Ambient conditions.Ambient conditions. Ambient temperature.Ambient temperature. Humidity.Humidity. Barometric pressure.Barometric pressure.

Different brands of dynamometers Different brands of dynamometers have different capabilities.have different capabilities.


First dynamometer was called a First dynamometer was called a prony brake.prony brake.

DynamometersDynamometers Prony brake was made of wood and leather.Prony brake was made of wood and leather. Wood block mechanism attached to ouput Wood block mechanism attached to ouput

shaft of engine.shaft of engine. Lever arm rests on a scale (like a bathroom Lever arm rests on a scale (like a bathroom

scale).scale). As engine is run, thumb screws are As engine is run, thumb screws are

tightened until rpm is steady.tightened until rpm is steady. Force on scale is read and rpm is recorded.Force on scale is read and rpm is recorded. Very primative.Very primative.


Different types of dynamometer Different types of dynamometer mechanisms.mechanisms.

Type of dynamometer is determined by Type of dynamometer is determined by it absorption unit.it absorption unit. The absorption unit is what loads the The absorption unit is what loads the

engine.engine. Eddy current or electromagnet brake.Eddy current or electromagnet brake. Hysteresis type is used for small Hysteresis type is used for small

engine dyno’s (<200 HP).engine dyno’s (<200 HP).


Electric motor/generator type.Electric motor/generator type. Has the ability to both load the engine Has the ability to both load the engine

and motor it.and motor it. This can be useful for measuring the This can be useful for measuring the

amount of friction when the engine is amount of friction when the engine is motored.motored.

Hydraulic brakeHydraulic brake Output shaft drives gear-drive pumpOutput shaft drives gear-drive pump Variable orifice on outside of the pumpVariable orifice on outside of the pump


Water brakeWater brake Have high load capacityHave high load capacity Low costLow cost Uses something similar to a torque Uses something similar to a torque

converter in an automatic transmission converter in an automatic transmission to load the engine.to load the engine.

DynamometersDynamometers Inertial Dynamometer.Inertial Dynamometer.

Dynojet Dyno’s, which are the most popular Dynojet Dyno’s, which are the most popular dynamometers, are inertial.dynamometers, are inertial.

Do not have the ability to load the engine.Do not have the ability to load the engine. Works by spinning a large, heavy drum.Works by spinning a large, heavy drum. Horsepower and torque are ‘interpolated’ by Horsepower and torque are ‘interpolated’ by

how fast it takes to spin up the drum.how fast it takes to spin up the drum. Readings are typically 10% higher than other Readings are typically 10% higher than other

dynamometers.dynamometers. Many people use the term DHP (Dynojet Many people use the term DHP (Dynojet

horsepower) instead of wheel horsepower.horsepower) instead of wheel horsepower. They are inexpensive and therefore popular.They are inexpensive and therefore popular.


Different types of horsepower and torque Different types of horsepower and torque measurements.measurements.

Brake torque and means it was measured Brake torque and means it was measured with a dynamometer which has the ability to with a dynamometer which has the ability to load the engine.load the engine.

Torque is referred to as ‘Brake Torque’Torque is referred to as ‘Brake Torque’ BHP = ‘Brake Horsepower’BHP = ‘Brake Horsepower’ HP measured at the wheels on a chassis HP measured at the wheels on a chassis

dyno is called WHP or ‘Wheel Horsepower’.dyno is called WHP or ‘Wheel Horsepower’. Dynojet horsepower sometimes called ‘DHP’.Dynojet horsepower sometimes called ‘DHP’.


There are 2 basic types of There are 2 basic types of dynamometers.dynamometers. Engine dynamometer.Engine dynamometer. Chassis dynamometer.Chassis dynamometer.

An engine dynamometer tests the An engine dynamometer tests the engine only.engine only.

A chassis dynamometer test the engine A chassis dynamometer test the engine while it is in the car, therefore it is while it is in the car, therefore it is also testing the drivetrain.also testing the drivetrain.


Engine dynamometers.Engine dynamometers. Some common manufacturers.Some common manufacturers.

SuperflowSuperflow.. Superflow was originally ‘Go Power Dyno’s’Superflow was originally ‘Go Power Dyno’s’ First dyno was installed at Dema Elgins shop in First dyno was installed at Dema Elgins shop in

Redwood City.Redwood City. California Dynamometer was run for years out of California Dynamometer was run for years out of

Dema’s shop by owner Gerard Rainey.Dema’s shop by owner Gerard Rainey. Shop has moved to San Carlos.Shop has moved to San Carlos. Superflow offers a wide variety of engine and chassis Superflow offers a wide variety of engine and chassis

dynamometers.dynamometers. Image of Image of DemaDema Ferrari 206 engine on Ferrari 206 engine on SuperflowSuperflow Dyno. Dyno.

DynamometersDynamometers Some common manufacturersSome common manufacturers

Mustang Dynamometer.Mustang Dynamometer. Offers a complete line of engine and chassis Offers a complete line of engine and chassis

dynamometers.dynamometers. Eddy current type.Eddy current type.

Taylor DynamometerTaylor Dynamometer Hydraulic and eddy current types.Hydraulic and eddy current types. I don’t have experience with there but they look to be I don’t have experience with there but they look to be

dynamometers for large powerplants like diesel dynamometers for large powerplants like diesel engines.engines.

DTS (Dynamic Test Systems)DTS (Dynamic Test Systems) Offers complete line of engine dynamometers.Offers complete line of engine dynamometers. Also sells valve spring dynamometers.Also sells valve spring dynamometers. Recently merged with Superflow.Recently merged with Superflow.


Parts of a dynamometerParts of a dynamometer Test standTest stand

This is what the engine is bolted to.This is what the engine is bolted to. Usually has wheels so engine can be Usually has wheels so engine can be

removed from it quickly and another engine removed from it quickly and another engine put in its place.put in its place.

Engine dyno operators usually have Engine dyno operators usually have multiple stands so engines can be swapped multiple stands so engines can be swapped out quickly.out quickly.


Cooling towerCooling tower Contains coolant hose connections that Contains coolant hose connections that

connect to engine.connect to engine. Used instead of a radiator.Used instead of a radiator. Can be used to keep engine temperature Can be used to keep engine temperature

constantconstant This is important for getting consistent readings.This is important for getting consistent readings.

Absorption unitAbsorption unit There are different types as mentioned There are different types as mentioned

earlier in presentation.earlier in presentation.


Sensor boxSensor box Has leads for the different types of Has leads for the different types of

sensors.sensors. May have basic gauges on it also.May have basic gauges on it also.

Oil pressure.Oil pressure. Coolant temperature.Coolant temperature. This is so if someone is in the dyno room they This is so if someone is in the dyno room they

can keep an eye on the vital basics.can keep an eye on the vital basics.

Throttle actuatorThrottle actuator Throttle is operated remotely.Throttle is operated remotely.


Dyno roomDyno room Room contains dynamometer.Room contains dynamometer. Has provisions for supplying fresh air Has provisions for supplying fresh air

into roominto room Has large exhaust fans for getting Has large exhaust fans for getting

exhaust fumes out.exhaust fumes out. Flexible exhaust tubes mount to exhaust.Flexible exhaust tubes mount to exhaust.

Usually there is a tool box kept in room Usually there is a tool box kept in room for working on the engine.for working on the engine.

DynamometersDynamometers Observation booth: Observation booth: Gerard RaineyGerard Rainey

InstrumentsInstruments TorqueTorque RPM (Tachometer)RPM (Tachometer) TemeraturesTemeratures Ambient conditions (weather)Ambient conditions (weather)

ControlsControls ThrottleThrottle LoadLoad

Today’s dynamometers usually just have a computer Today’s dynamometers usually just have a computer instead of analog instruments.instead of analog instruments.

However they still have mechanical controls for However they still have mechanical controls for throttle and load.throttle and load.


Chassis dynamometers.Chassis dynamometers. Some common manufacturers.Some common manufacturers.

SuperflowSuperflow Mustang DynamometersMustang Dynamometers DynapackDynapack

Maker of hub mounted dynosMaker of hub mounted dynos Dyno DynamicsDyno Dynamics DynojetDynojet

Not a true dynamometer, an inertial Not a true dynamometer, an inertial dynamometer.dynamometer.


Roller typeRoller type Drive wheels ride on a large textured Drive wheels ride on a large textured

drum which is connected to the drum which is connected to the adsorption unit.adsorption unit.

Vehicle is tethered down with tie-straps.Vehicle is tethered down with tie-straps. If tie-straps break, vehicle will launch.If tie-straps break, vehicle will launch. Variables need to be kept constant.Variables need to be kept constant.

Tire pressure.Tire pressure. Strap tension.Strap tension. Sample video – DynojetSample video – Dynojet Sample video - MustangSample video - Mustang

DynamometersDynamometers Types of absorption unitsTypes of absorption units

Same as with engine dynosSame as with engine dynos Depends on manufacturerDepends on manufacturer

Exception is the DynojetException is the Dynojet Uses an inertial drumUses an inertial drum Large, heavy steel drum.Large, heavy steel drum. Vehicle is accelerated when on rollersVehicle is accelerated when on rollers The time it takes to accelerate the drum is The time it takes to accelerate the drum is

‘interpolated’ into horsepower and torque.‘interpolated’ into horsepower and torque. Can not load engine and hold rpm constant.Can not load engine and hold rpm constant. Readings are normally 10% higher than other dynos.Readings are normally 10% higher than other dynos. They are low cost, therefore very popular among the They are low cost, therefore very popular among the

‘tuner’ crowd.‘tuner’ crowd.


Hub typeHub type Bolts directly to hubsBolts directly to hubs Can be used for 2 wheel drive or 4 wheel Can be used for 2 wheel drive or 4 wheel

drivedrive Eliminates variables associated with roller Eliminates variables associated with roller

types.types. Are only a few manufacturers that Are only a few manufacturers that

currently make them.currently make them. Dynapack is the most popular.Dynapack is the most popular. Sample video – dynapack.Sample video – dynapack.


A dynamometer is only a tool.A dynamometer is only a tool. A tool for verifying power goals have A tool for verifying power goals have

been met.been met. A tool for confirming that a A tool for confirming that a

modification has made the increase in modification has made the increase in power which was anticipated.power which was anticipated.

Results from one dyno should not be Results from one dyno should not be compared with results from another compared with results from another dyno, especially of a different brand.dyno, especially of a different brand.


Before and after test.Before and after test. Vehicle or engine is tested before Vehicle or engine is tested before

installing a performance part.installing a performance part. Vehicle is tested after performance part Vehicle is tested after performance part

is installed under same conditions.is installed under same conditions. If weather is different results will be If weather is different results will be

different even with corrections.different even with corrections. A before test on a Dynojet and an after A before test on a Dynojet and an after

test on a Mustang is invalid.test on a Mustang is invalid.


Before doing the dyno run.Before doing the dyno run. Temperatures must be stabilized to Temperatures must be stabilized to

ensure repeatability.ensure repeatability. Coolant tempCoolant temp Engine oil tempEngine oil temp Transmission oil tempTransmission oil temp Intake air tempIntake air temp

Doing runs one after another is a good Doing runs one after another is a good way to get inconsistent results.way to get inconsistent results.

DynamometersDynamometers Cooling fan for chassis dynoCooling fan for chassis dyno

Very important to have a very large fan in Very important to have a very large fan in front of vehicle during and after runs.front of vehicle during and after runs.

Most dyno operators do not own a proper fan.Most dyno operators do not own a proper fan. Sample photo – small fanSample photo – small fan Dinan has a 4 foot diameter fan with Dinan has a 4 foot diameter fan with

shrouding that narrows down to about 1 foot shrouding that narrows down to about 1 foot by 2 feet.by 2 feet.

Has 40 HP electric motorHas 40 HP electric motor Can blow air at 80 MPH.Can blow air at 80 MPH.

Large fan is especially important when testing Large fan is especially important when testing cars with intercoolers.cars with intercoolers.

DynamometersDynamometers CorrectionsCorrections

Since we can not control the weather, it is Since we can not control the weather, it is impossible to ensure consistent conditions during impossible to ensure consistent conditions during dyno runs.dyno runs.

Ambient temperatureAmbient temperature HumidityHumidity Barometric pressure.Barometric pressure.

Because of this, dynamometers have built in Because of this, dynamometers have built in corrections which adjust results to a standard.corrections which adjust results to a standard.

SAE (Society of Automotive Engineers) standard SAE (Society of Automotive Engineers) standard J1349J1349

UncorrectedUncorrected People sometimes use to make it seem their engine People sometimes use to make it seem their engine

made more power than it did.made more power than it did. Do the run on a cold, dry day for maximum air density.Do the run on a cold, dry day for maximum air density.

DynamometersDynamometers Dyno videosDyno videos

Cosworth 2.3 LiterCosworth 2.3 Liter Mitsubishi LancerMitsubishi Lancer Lamborghini GallardoLamborghini Gallardo Renault F1Renault F1

Dyno FAIL videosDyno FAIL videos Mitsubishi EVOMitsubishi EVO Drag carDrag car Unknown engineUnknown engine

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