1. Review 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 pushing on the end of the wrench is said to produce 1 foot-pounds of torque. A 1 foot wrench with 1 pound of force pushing on the end of the wrench is said to produce 1 foot-pounds of torque. There does not need to be motion to create torque, unlike horsepower. There does not need to be motion to create torque, unlike horsepower. Torque is a SCALAR measurement, which means it has magnitude only. Torque is a SCALAR measurement, which means it has magnitude only. Electric motors can produce torque at zero rpm. Electric motors can produce torque at zero rpm. Engines can’t because they won’t run at low rpm. Engines can’t because they won’t run at low rpm.

2. Review of HP and Torque Horsepower is a measure of work. Horsepower is a measure of work. Horsepower can only be calculated after torque and rpm are known. Horsepower can only be calculated after torque and rpm are known. Horsepower is a VECTOR measurement, meaning that it has both magnitude and direction. Horsepower is a VECTOR measurement, meaning that it has both magnitude and 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 rotating to create horsepower. Because of this, the engine must be rotating to create horsepower.

3. Review 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 can lift this much. We don’t know how many times per minute he 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 minute’ ‘A weightlifter can lift 400 lbs 5 times per minute’ Not only does this tell us how much he can lift but how much per minute. Not only does this tell us how much he can lift but how much per minute. We can compare this to horsepower. We can compare this to horsepower.

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

5. Dynamometers Today’s dynamometers take a variety of measurements. Today’s dynamometers take a variety of measurements. Air/fuel ratio (AFR). Air/fuel ratio (AFR). Air/fuel ratio is measured using a device calling an air/fuel ratio analyzer. Air/fuel ratio is measured using a device calling an air/fuel ratio analyzer. A popular AFR analyzer is MoTeC’s PLM. A popular AFR analyzer is MoTeC’s PLM.PLM High end units are made by Horiba or Labcell. High end units are made by Horiba or Labcell.HoribaLabcellHoribaLabcell Hobby level kits are made by various manufacturers and are available by companies such as Summit Racing. Hobby level kits are made by various manufacturers and are available by companies such as Summit Racing.

6. Dynamometers The air/fuel ratio analyzer has a sensor, similar to an O2 sensor, which is bolted into the exhaust using a ‘bung’. The air/fuel ratio analyzer has a sensor, similar to an O2 sensor, which is bolted into the exhaust using a ‘bung’. The sensor is called a UEGO (universal exhaust gas oxygen) sensor. The sensor is called a UEGO (universal 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 or air/fuel ratio sensor found in a normal passenger car or truck. It is not the same as an oxygen sensor or air/fuel ratio sensor found in a normal passenger car or truck.

7. Dynamometers The high end air/fuel ratio analyzers use a sensor which is very accurate and has a very high sampling rate. The high end air/fuel ratio analyzers use a sensor which is very accurate and has a very high sampling rate. The ‘sampling rate’ is the speed at which the measurements are updated. The ‘sampling rate’ is the speed at which the measurements are updated. Air/fuel ratio is defined as the ratio, by weight, of air to fuel. Air/fuel ratio is defined as the ratio, by weight, of air to fuel. The stoichiometric ratio, also known as ‘stoich’, is 14.7:1 for gasoline. The stoichiometric ratio, also known as ‘stoich’, is 14.7:1 for gasoline.

8. Dynamometers The stoichiometric ratio is that ratio at which every molecule of air will chemically react with every molecule of fuel. The stoichiometric ratio is that ratio at which every molecule of air will chemically react with every molecule of fuel. In practice, this never happens – there are always molecules that do not react and leave via the tailpipe. In practice, this never happens – there are always molecules that do not react and leave via the tailpipe. A 14.7:1 AFR would be 14.7 lbs of air to 1 pound of fuel. A 14.7:1 AFR would be 14.7 lbs of air to 1 pound of fuel.

9. Dynamometers An AFR less than 14.7:1 is considered ‘rich’. An AFR less than 14.7:1 is considered ‘rich’. This means that there is more fuel in the mixture than is chemically correct. This means that there is more fuel in the 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 ‘lean’. An AFR more than 14.7:1 is considered ‘lean’. This means that there is less fuel in the mixture than is chemically correct. This means that there is less fuel in the mixture than is chemically correct. For example, 16:1 AFR. For example, 16:1 AFR.

10. Dynomometers 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 a 12.5:1 AFR For example,.85 Lambda corresponds to a 12.5:1 AFR A 1.1 Lambda corresponds to a 16:1 AFR. A 1.1 Lambda corresponds to a 16:1 AFR.

11. Dynamometers Coolant temperature. Coolant temperature. It is very important that the engine coolant temperature be consistent from one dyno ‘pull’ to the next or readings could be inaccurate. It is very important that the engine coolant temperature be consistent from one dyno ‘pull’ to the next or readings could be inaccurate. Exhaust temperature (using thermocouples). Exhaust temperature (using thermocouples). A thermocouple is a device which plugs into each individual exhaust port and measures temperature. A thermocouple is a device which plugs into each individual exhaust port and measures temperature.

12. Dynamometers By probing individual exhaust ports you can determine if there is a problem in one cylinder. Or, on a carbureted engine, you can determine if equal amounts of fuel and air is being delivery to each cylinder. By probing individual exhaust ports you can determine if there is a problem in one cylinder. Or, on a carbureted engine, you can determine if equal amounts of fuel and air is being delivery to each cylinder. Lean cylinders will have higher temperatures that rich cylinders. Lean cylinders will have higher temperatures that rich cylinders. The extra fuel in a rich mixture causes combustion to be cooler due to a phenomena called ‘latent heat of vaporization’. The extra fuel in a rich mixture causes combustion to be cooler due to a phenomena called ‘latent heat of vaporization’.

13. Dynamometers Brake specific fuel consumption (BSFC). Brake specific fuel consumption (BSFC). BSFC is a measure of fuel efficiency. BSFC is a measure of fuel efficiency. BSFC is the rate of fuel consumed divided by the power produced. BSFC is the rate of fuel consumed divided by the power produced. BSFC is expressed in ‘pounds per horsepower hour’ or lbs per hp/hr. BSFC is expressed in ‘pounds per horsepower hour’ or lbs per hp/hr.

14. Dynamometers An efficient engine might be around.35 lbs per hp/hr. An efficient engine might be around.35 lbs per hp/hr. An inefficient engine might be around.60 lbs per hp/hr. An inefficient engine might be around.60 lbs per hp/hr. It is possible that both these engine make the same amount of horsepower. It is possible that both these engine make the same amount of horsepower. The engine with.35 lbs. per hp/hr would get considerably better fuel consumption. The engine with.35 lbs. per hp/hr would get considerably better fuel consumption. Fuel efficiency very important in endurance racing (races lasting a long time – 4, 12, or 24 hours) for less pit stops. Fuel efficiency very important in endurance racing (races lasting a long time – 4, 12, or 24 hours) for less pit stops.

15. Dynamometers Intake air temperature. Intake air temperature. The temperature of the air coming into the engine. The temperature of the air coming into the engine. Air temperature has a very large effect on power output. Air temperature has a very large effect on power output. Colder air = more power. Colder air = more power. Cold air is more dense and therefore contains more oxygen per unit volume. Cold air is more dense and therefore contains more oxygen per unit volume.

16. Dynamometers Ignition timing and advance curves. Ignition timing and advance curves. Some dynamometers can track ignition timing advance. Some dynamometers can track ignition timing advance. Some dynamometers have integrated detonation detection equipment. Some dynamometers have integrated detonation detection equipment.

17. Dynamometers Ambient conditions. Ambient conditions. Ambient temperature. Ambient temperature. Humidity. Humidity. Barometric pressure. Barometric pressure. Different brands of dynamometers have different capabilities. Different brands of dynamometers have different capabilities.

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

19. Dynamometers Prony brake was made of wood and leather. Prony brake was made of wood and leather. Wood block mechanism attached to ouput shaft of engine. Wood block mechanism attached to ouput shaft of engine. Lever arm rests on a scale (like a bathroom scale). Lever arm rests on a scale (like a bathroom scale). As engine is run, thumb screws are tightened until rpm is steady. As engine is run, thumb screws are 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.

20. Dynamometers Different types of dynamometer mechanisms. Different types of dynamometer mechanisms. Type of dynamometer is determined by it absorption unit. Type of dynamometer is determined by it absorption unit. The absorption unit is what loads the engine. The absorption unit is what loads the engine. Eddy current or electromagnet brake. Eddy current or electromagnet brake. Hysteresis type is used for small engine dyno’s (<200 HP). Hysteresis type is used for small engine dyno’s (<200 HP).

21. Dynamometers Electric motor/generator type. Electric motor/generator type. Has the ability to both load the engine and motor it. Has the ability to both load the engine and motor it. This can be useful for measuring the amount of friction when the engine is motored. This can be useful for measuring the amount of friction when the engine is motored. Hydraulic brake Hydraulic brake Output shaft drives gear-drive pump Output shaft drives gear-drive pump Variable orifice on outside of the pump Variable orifice on outside of the pump

22. Dynamometers Water brake Water brake Have high load capacity Have high load capacity Low cost Low cost Uses something similar to a torque converter in an automatic transmission to load the engine. Uses something similar to a torque converter in an automatic transmission to load the engine.

23. Dynamometers Inertial Dynamometer. Inertial Dynamometer. Dynojet Dyno’s, which are the most popular dynamometers, are inertial. Dynojet Dyno’s, which are the most popular 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 how fast it takes to spin up the drum. Horsepower and torque are ‘interpolated’ by how fast it takes to spin up the drum. Readings are typically 10% higher than other dynamometers. Readings are typically 10% higher than other dynamometers. Many people use the term DHP (Dynojet horsepower) instead of wheel horsepower. Many people use the term DHP (Dynojet horsepower) instead of wheel horsepower. They are inexpensive and therefore popular. They are inexpensive and therefore popular.

24. Dynamometers Different types of horsepower and torque measurements. Different types of horsepower and torque measurements. Brake torque and means it was measured with a dynamometer which has the ability to load the engine. Brake torque and means it was measured with a dynamometer which has the ability to 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 dyno is called WHP or ‘Wheel Horsepower’. HP measured at the wheels on a chassis dyno is called WHP or ‘Wheel Horsepower’. Dynojet horsepower sometimes called ‘DHP’. Dynojet horsepower sometimes called ‘DHP’.

25. Dynamometers There are 2 basic types of dynamometers. There are 2 basic types of dynamometers. Engine dynamometer. Engine dynamometer. Chassis dynamometer. Chassis dynamometer. An engine dynamometer tests the engine only. An engine dynamometer tests the engine only. A chassis dynamometer test the engine while it is in the car, therefore it is also testing the drivetrain. A chassis dynamometer test the engine while it is in the car, therefore it is also testing the drivetrain.

26. Dynamometers Engine dynamometers. Engine dynamometers. Some common manufacturers. Some common manufacturers. Superflow. Superflow. Superflow. Superflow was originally ‘Go Power Dyno’s’ Superflow was originally ‘Go Power Dyno’s’ First dyno was installed at Dema Elgins shop in Redwood City. First dyno was installed at Dema Elgins shop in Redwood City. California Dynamometer was run for years out of Dema’s shop by owner Gerard Rainey. California Dynamometer was run for years out of 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 dynamometers. Superflow offers a wide variety of engine and chassis dynamometers. Image of Dema Ferrari 206 engine on Superflow Dyno. Image of Dema Ferrari 206 engine on Superflow Dyno. Image of Dema Ferrari 206 engine on Superflow Dyno. Image of Dema Ferrari 206 engine on Superflow Dyno.

27. Dynamometers Some common manufacturers Some common manufacturers Mustang Dynamometer. Mustang Dynamometer. Mustang Dynamometer. Mustang Dynamometer. Offers a complete line of engine and chassis dynamometers. Offers a complete line of engine and chassis dynamometers. Eddy current type. Eddy current type. Taylor Dynamometer Taylor Dynamometer Taylor Dynamometer Taylor Dynamometer Hydraulic and eddy current types. Hydraulic and eddy current types. I don’t have experience with there but they look to be dynamometers for large powerplants like diesel engines. I don’t have experience with there but they look to be dynamometers for large powerplants like diesel engines. DTS (Dynamic Test Systems) DTS (Dynamic Test Systems) 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.

28. Dynamometers Parts of a dynamometer Parts of a dynamometer Test stand Test stand This is what the engine is bolted to. This is what the engine is bolted to. Usually has wheels so engine can be removed from it quickly and another engine put in its place. Usually has wheels so engine can be removed from it quickly and another engine put in its place. Engine dyno operators usually have multiple stands so engines can be swapped out quickly. Engine dyno operators usually have multiple stands so engines can be swapped out quickly.

29. Dynamometers Cooling tower Cooling tower Contains coolant hose connections that connect to engine. Contains coolant hose connections that connect to engine. Used instead of a radiator. Used instead of a radiator. Can be used to keep engine temperature constant Can be used to keep engine temperature constant This is important for getting consistent readings. This is important for getting consistent readings. Absorption unit Absorption unit There are different types as mentioned earlier in presentation. There are different types as mentioned earlier in presentation.

30. Dynamometers Sensor box Sensor box Has leads for the different types of sensors. Has leads for the different types of 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 can keep an eye on the vital basics. This is so if someone is in the dyno room they can keep an eye on the vital basics. Throttle actuator Throttle actuator Throttle is operated remotely. Throttle is operated remotely.

31. Dynamometers Dyno room Dyno room Room contains dynamometer. Room contains dynamometer. Has provisions for supplying fresh air into room Has provisions for supplying fresh air into room Has large exhaust fans for getting exhaust fumes out. Has large exhaust fans for getting exhaust fumes out. Flexible exhaust tubes mount to exhaust. Flexible exhaust tubes mount to exhaust. Usually there is a tool box kept in room for working on the engine. Usually there is a tool box kept in room for working on the engine.

32. Dynamometers Observation booth: Gerard Rainey Observation booth: Gerard RaineyGerard RaineyGerard Rainey Instruments Instruments Torque Torque RPM (Tachometer) RPM (Tachometer) Temeratures Temeratures Ambient conditions (weather) Ambient conditions (weather) Controls Controls Throttle Throttle Load Load Today’s dynamometers usually just have a computer instead of analog instruments. Today’s dynamometers usually just have a computer instead of analog instruments. However they still have mechanical controls for throttle and load. However they still have mechanical controls for throttle and load.

33. Dynamometers Chassis dynamometers. Chassis dynamometers. Some common manufacturers. Some common manufacturers. Superflow Superflow Mustang Dynamometers Mustang Dynamometers Dynapack Dynapack Dynapack Maker of hub mounted dynos Maker of hub mounted dynos Dyno Dynamics Dyno Dynamics Dyno Dynamics Dyno Dynamics Dynojet Dynojet Dynojet Not a true dynamometer, an inertial dynamometer. Not a true dynamometer, an inertial dynamometer.

34. Dynamometers Roller type Roller type Drive wheels ride on a large textured drum which is connected to the adsorption unit. Drive wheels ride on a large textured drum which is connected to the 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 – Dynojet Sample video – Dynojet Sample video – Dynojet Sample video – Dynojet Sample video - Mustang Sample video - Mustang Sample video - Mustang Sample video - Mustang

35. Dynamometers Types of absorption units Types of absorption units Same as with engine dynos Same as with engine dynos Depends on manufacturer Depends on manufacturer Exception is the Dynojet Exception is the Dynojet Uses an inertial drum Uses an inertial drum Large, heavy steel drum. Large, heavy steel drum. Vehicle is accelerated when on rollers Vehicle is accelerated when on rollers The time it takes to accelerate the drum is ‘interpolated’ into horsepower and torque. The time it takes to accelerate the drum is ‘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 ‘tuner’ crowd. They are low cost, therefore very popular among the ‘tuner’ crowd.

36. Dynamometers Hub type Hub type Bolts directly to hubs Bolts directly to hubs Can be used for 2 wheel drive or 4 wheel drive Can be used for 2 wheel drive or 4 wheel drive Eliminates variables associated with roller types. Eliminates variables associated with roller types. Are only a few manufacturers that currently make them. Are only a few manufacturers that currently make them. Dynapack is the most popular. Dynapack is the most popular. Sample video – dynapack. Sample video – dynapack. Sample video – dynapack. Sample video – dynapack.

37. Dynamometers A dynamometer is only a tool. A dynamometer is only a tool. A tool for verifying power goals have been met. A tool for verifying power goals have been met. A tool for confirming that a modification has made the increase in power which was anticipated. A tool for confirming that a modification has made the increase in power which was anticipated. Results from one dyno should not be compared with results from another dyno, especially of a different brand. Results from one dyno should not be compared with results from another dyno, especially of a different brand.

38. Dynamometers Before and after test. Before and after test. Vehicle or engine is tested before installing a performance part. Vehicle or engine is tested before installing a performance part. Vehicle is tested after performance part is installed under same conditions. Vehicle is tested after performance part is installed under same conditions. If weather is different results will be different even with corrections. If weather is different results will be different even with corrections. A before test on a Dynojet and an after test on a Mustang is invalid. A before test on a Dynojet and an after test on a Mustang is invalid.

39. Dynamometers Before doing the dyno run. Before doing the dyno run. Temperatures must be stabilized to ensure repeatability. Temperatures must be stabilized to ensure repeatability. Coolant temp Coolant temp Engine oil temp Engine oil temp Transmission oil temp Transmission oil temp Intake air temp Intake air temp Doing runs one after another is a good way to get inconsistent results. Doing runs one after another is a good way to get inconsistent results.

40. Dynamometers Cooling fan for chassis dyno Cooling fan for chassis dyno Very important to have a very large fan in front of vehicle during and after runs. Very important to have a very large fan in 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 fan Sample photo – small fan Sample photo – small fan Sample photo – small fan Dinan has a 4 foot diameter fan with shrouding that narrows down to about 1 foot by 2 feet. Dinan has a 4 foot diameter fan with shrouding that narrows down to about 1 foot by 2 feet. Has 40 HP electric motor Has 40 HP electric motor Can blow air at 80 MPH. Can blow air at 80 MPH. Large fan is especially important when testing cars with intercoolers. Large fan is especially important when testing cars with intercoolers.

41. Dynamometers Corrections Corrections Since we can not control the weather, it is impossible to ensure consistent conditions during dyno runs. Since we can not control the weather, it is impossible to ensure consistent conditions during dyno runs. Ambient temperature Ambient temperature Humidity Humidity Barometric pressure. Barometric pressure. Because of this, dynamometers have built in corrections which adjust results to a standard. Because of this, dynamometers have built in corrections which adjust results to a standard. SAE (Society of Automotive Engineers) standard J1349 SAE (Society of Automotive Engineers) standard J1349 Uncorrected Uncorrected People sometimes use to make it seem their engine made more power than it did. People sometimes use to make it seem their engine 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.

42. Dynamometers Dyno videos Dyno videos Cosworth 2.3 Liter Cosworth 2.3 Liter Cosworth 2.3 Liter Cosworth 2.3 Liter Mitsubishi Lancer Mitsubishi Lancer Mitsubishi Lancer Mitsubishi Lancer Lamborghini Gallardo Lamborghini Gallardo Lamborghini Gallardo Lamborghini Gallardo Renault F1 Renault F1 Renault F1 Renault F1 Dyno FAIL videos Dyno FAIL videos Mitsubishi EVO Mitsubishi EVO Mitsubishi EVO Mitsubishi EVO Drag car Drag car Drag car Drag car Unknown engine Unknown engine Unknown engine Unknown engine