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ENGINE TECH TIPS ENGINE DYNAMOMETER TESTING BASICS TYPES OF ENGINE Electric dynos rotate a generator to absorb Another method of power testing is the step DYNAMOMETERS engine output; this yields an electric output method. This can be controlled manually There are many types of dynamometers for that can be accurately measured. Typically, or by an automated test where the dyno testing engines: Water Brake, Eddy-Current, Electric dynos can be used to spin a non-fi ring soft ware controls the engine operation. The Electric…just to name a few. Depending on engine and measure pumping losses and dyno controller is set to the fi rst rpm test point availability and engine application, Ford friction. Those types of losses are diffi cult to and the throttle actuator is slowly opened Racing utilizes any of those mentioned. The ascertain in conventional dyno testing. to the full throttle point. The controller will basic function of each of these dynamometers maintain the rpm of the engine to the set (referred to as dynos from this point forward) METHODS OF TESTING point. In the manual mode, the operator will is the same. Each applies a diff erent method Once the engine is installed in a test cell, and observe the data until stable and then record. to absorb the energy output of the engine. The all desired operating parameters are instru- In automated mode, the dyno will hold the engine output is measured as torque (work) mented, testing can begin. The dyno is capable throttle and rpm for a set period of time and and power is calculated. The energy produced of absorbing an infi nite number of operating automatically record the data. In either case, by the engine is absorbed by the dyno and conditions ranging from idle to WOT (wide this testing provides good steady readings and eventually dissipated as heat. Dynos measure open throttle) and idle rpm to rpm’s beyond makes for good repeatable runs. The above this engine output over a range of engine peak horsepower. In cases where the dyno is procedure will be repeated for all desired rpm conditions that vary with speed and load. operated manually, the operator will set the test points. Temperature, pressures, air/fuel ratio, water, oil, rpm value via a controller. The operator then fuel and airfl ow measurements are elements opens the throttle via a throttle actuator and Results of power testing are used in the of the test cell. The accurate measurement applies load to the dyno. As the throttle is design of crate engine packages and for of these parameters is just as vital to good opened further, the dyno will control the rpm marketing/sales. For further information on testing as the dyno itself. The test cell that to the set point and the load will increase until interpreting results, see article on “Correction houses a dyno can vary widely. Conditioned full throttle is reached. Many types of testing Factors, Observed and Corrected Horsepower airfl ow, exhaust evacuation and fuel delivery exist for evaluating engine performance. Crate and Torque.” (See page 60.) must be adequate for the power level of the engine testing consists of power development, engine tested. Shortfalls in any of these areas durability, idle stability, etc. DURABILITY TESTING can impact the integrity of the test. Durability testing varies by engine application POWER TESTING and confi guration. The type of engine and Ford Racing tests our crate engine off erings on Methods for performing power tests or power where it will be used can infl uence the type any of the above-mentioned types of dynos. runs vary by dyno facility and engine applica- of durability testing greatly. For example, The type depends on test cell availability and tion. Acceleration tests (sometimes referred durability testing criteria for a sealed circle track type of engine application (street, sealed circle to as ramp tests) are controlled completely by crate engine will be determined by minimum track, etc.). The engine is directly coupled to dyno soft ware through the dyno controller and and maximum track conditions. Durability the dyno via a prop shaft . This type of testing throttle actuator. The rpm and transient times testing for a street application crate engine will yields brake power and torque. Test results are are programmed by the operator and, once set, be determined by peak torque and horsepower brake, horsepower and brake torque because the controller takes the engine through the test. for the given components. Testing conditions measurements are taken directly from the These tests typically do not let the engine stabi- are typically WOT or high-load conditions and crankshaft output. lize at any given speed and data is collected variable rpm to cover as wide of a range as throughout the ramp. For example: The test possible. In short, durability testing criteria vary, Water Brake dynos absorb energy by pumping would begin at idle. Slowly, the throttle will be but the goal is the same. The goal is to produce water through various orifi ces. Speed and load opened and rpm controlled to the fi rst chosen an accelerated wear condition that exceeds the are controlled through a feedback loop of rpm test point. Eventually the throttle will reach normal application of the engine as designed. inlet and outlet valves. Water Brake dynos are WOT. From then, the rpm will increase at a typically capable of absorbing very high engine given rate of rpm/time until the maximum test outputs and rpm. rpm is reached. Test data is recorded through- out the entire run. Finally the controller will Eddy-Current dynos rotate a disc through a close the throttle and return the engine to idle. magnetic fi eld. This magnetic fi eld can be varied in strength to control the rpm of the disc. These dynos are desirable for engine development due to very good rpm control. For important information about the proper usage of performance parts, please see page 14. See pages 286-292 for important safety, emissions and warranty information. www.fordracingparts.com 59


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