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Summary of change:
'''Take internet horsepower with a grain of salt''' Often very high (sometimes unbelievable) horsepower numbers are published. There are a few methods (wether applied intentionally or accidentally) to publish wrong results. * '''miscalibrated dyno''' ** a dyno is (or at least should be) calibrated. It can print any result if calibration is wrong. Installers often favor dyno-s showing high HP instead of real HP, which keeps this trend live * '''measuring WHP, and apply a presumed multiplier''' for crank HP. Often the multiplied result is published as WHP (which it is not, by far). The factor is usually * 1.2 .. * 1.25 depending on front WD/rear WD/4WD and rule of thumb (so they say 500 HP when they measure 400 HP on the wheel). ** the '''multiplier often assumes tire slip that is just wrong''' (eg. would melt the rubber) or not present (eg. using a dyno where you bolt a dyno to each hub: makes the conversion factor MUCH smaller). When you compare engines, before deciding to believe or not, it's a very good idea to * calculate the VE (eg. in a spreadsheet). Either real VE numbers, or just scale the crank-HP numbers to 1.0L 100kPa and 6000 RPM ** best to calc for (/scale) the whole torque curve if possible (often not easy, as the boosted MAP is not published for each RPM) * Compare with factory numbers (like to a Honda VTEC NA engine) that are usually right ** they measure the crank HP (so without driving losses and fictive multiplier), on the best out of 10 engines in circumstances like -20C MAT that you will never be able to reproduce at home on the dyno, but at least those are not fictive numbers. If the VE numbers for an engine at MAP=250 kPa and 9000 RPM (especially if it's 2 valve head :-) calculates to be higher than a factory variable valve Honda/Toyota at MAP=100kPa and 8000 RPM, start to doubt.
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