Doctor Diesel

Knowledge is Power

Web01Your clarification is required please Doctor. In the Diesel Car Data Files, are the power and torque figures as measured at the flywheel or at wheel values? Reason for asking: I have just had my 2009 4×2 Ford Kuga (65,250 miles) dynamometer tested. The results show peak flywheel power as 166bhp at 3,780rpm, with peak torque of 285lb ft at 2,170rpm. Wheel values were 144bhp at 3,750rpm and 261lb ft at 2,110rpm. My son questions the figures, as he is under the impression that the data published in the sales blurb are flywheel values. Best wishes for the festive season and a preposterous New Year!
David Sayer

Of course if you measure the power output on a set of dynamometer rollers, then you can really only actually measure the power at the wheels. True, but what they do, after the power test run and with no power generated by the engine, is measure and record the power absorption of the transmission and drivetrain, all the way from max power down to tick-over speed. That is then added to the power measured at the wheels to give a pretty accurate estimate of the power at the flywheel, as measured by the manufacturers, on a bench dynamometer and with the engine out of the car. So the corrected dynamometer figures are pretty comparable with quoted figures, but we often see engines delivering significantly more power than the quoted output.

Typically, 2.0-litre TDI Volkswagen Group engines that were quoted at 140bhp for quite a few years often delivered 155bhp plus on a rolling road dynamometer. Presuming that I’m correct, and that your 2009 2WD Kuga engine is the 136PS (134bhp) engine, then your figures of 166bhp are pretty damned good. It seems that this engine, like the VAG 2.0-litre TDI unit, also typically exceeds quoted output figures. Superchips’ test figures on your model, standard and tuned by them, give 154bhp standard and 173bhp tuned, at around 3,500 to 3,600rpm, with torque figures pretty much in line of between 270lb ft and 290lb ft at around 2,300rpm.

So it sounds like your engine is in rude health, and probably has benefited from regular servicing and sensible driving! Hope that is good news for you and helps you understand the figures you were given. I’m rather surprised that they actually gave you the uncorrected “at the wheels” figures.

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