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Ford Racing Catalogue Web

ENGINE PERFORMANCE – TECH TIPS DYNAMOMETER TESTING AND FORD RACING CALIBRATIONS (continued...) sensitivity of torque relative to ignition timing. Basically this means that the closer the actual conditions are to the SAE J1349 standard (77 deg F inlet air, 29.31 inHg barometric pressure), the more comparable the results are to those quoted by the manufacturer. Unless otherwise explicitly stated,all horsepower numbers in the Ford Racing catalog have been determined by using the SAE J1349 standard. When testing a particular calibration or performance-enhancing part by performing back-to-back dyno runs, it is critical to keep test conditions as similar as possible between the runs. This sounds obvious, but is very commonly overlooked by many aftermarket companies who frequently publish dyno charts depicting large gains, but fail to give all the necessary data to show the tests were run under similar conditions. In order to be certain that the test conditions are as similar as possible, the following data is mandatory and needs to be collected for each run: • Ambient air temperature • Barometric pressure • Inlet air temperature (on a forced-induction car, this is usually downstream of the power adder) • Air/fuel (A/F) ratio (preferably upstream of any catalyst) Truly meaningful power numbers cannot be collected without this data! It is also a good idea to make sure the A/F ratio sensor (often called a “wideband” sensor) in use on the dyno has not been exposed to leaded fuel and has not been in service for an excessive period of time (greater than six months, depending on frequency of use). A/F ratio is the single most important parameter to measure accurately when doing any sort of dyno tuning, so it is critical the sensor is providing accurate information. When doing any PCM calibration on a dyno, the resulting calibration will only be as good as the A/F sensor. These additional inputs should be used for ideal dyno testing and calibration: • Air/fuel ratio and spark advance commanded by the PCM • Fuel injector pulsewidth • Fuel pump duty cycle (in the case of ERFS) • MAF sensor voltage • Fuel pressure • Engine oil temperature • Differential oil temperature For important information about the proper usage of performance parts, please see page 14. 150 Techline (800) FORD788 See pages 286-292 for important safety, emissions and warranty information.


Ford Racing Catalogue Web
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