Sunday, April 29, 2012

The difference between HP and PS and why it doesn't really matter.

With Audi releasing the details on its updated Q5 many publications took the time to properly convert the horsepower figures given in the Audi press release from . The result is the 225 European horsepower that Audi quoted in its press release is technically only worth 221 American/British horsepower, likewise the 272 horsepower from the 3.0T is technically 268 in the US. This small discrepancy occurs as European manufacturers use metric horsepower while American and British manufacturers use a term called mechanical horsepower which is 1.4% more powerful. However every one that did the conversion could have saved some time crunching the numbers and everyone would have been better off. For many years Audi (and a few other German manufacturers) have officially quoted the same exact horsepower rating regardless of units in Europe and in the US. There are a couple of reasons why this discrepancy shouldn't bother you. To start, the 1.4% difference is small enough anyways that it's probably quite close to the variation between one engine from the assembly line and another. To further shrink the gap, under "SAE certified horsepower" rule manufactures can report horsepower 1%  higher than what is observed. Finally, with the recent trend of many new forced induction engines from Audi and others often delivering advertised crank horsepower at the wheels the 1.4% difference becomes silly altogether.

*Perhaps too busy crunching the numbers many missed out on a little tidbit hidden in the Q5 press release, the next generations of the 2.0T and 3.0 TDI. Far from a simple uptune from 211 to 225 horsepower the updated 2.0T receives a new electronic cooling system, direct and port fuel injection, an exhaust manifold integrated into the cylinder head, and further enhancements to Audi's Valvelift system. It's unknown how soon the new 2.0T will reach the Audi lineup in the US. Likewise Audi says the 3.0 TDI V6 is also of a new more advanced design wtih more torque (22 extra lb-ft) than before. Stay tuned to see what happens with the new engines.

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