*Not all dynamometers are created equal. Sometimes it's easy to manipulate and alter numbers to suit someone's needs (or ego). For example, this 2006 Audi A3 (with about 4,000 miles on the odometer) was taken to a few different dynos and, in stock form, produced 164 hp on dyno A and 197 on dyno B, both in third gear. During another test, in fourth gear, it netted a little over 200 hp. Ultimately, the best thing when testing is to use the same dyno for all tests, the same gear, at the same temperature and with the same fuel quality. It's also important to make sure that the dyno's settings are always the same, since it's easy to make a few simple setting changes and show large gains without even altering the vehicle.
2006 Audi A3
Transmission: six-speed S tronic
Testing octane: 91
Dyno type: Mustang dynamometer
Outside temperature: 68 degrees F
Humidity: 30 percent
Test gear: third
Peak wheel-hp: 167 @ 6323 rpm
Peak wheel-torque: 181 lb-ft @ 2802 rpm
The vehicle was in perfect running condition with no issues and had an oil change not long before the test. The intake system was fully pressure-tested and there were no leaks in the PCV or intercooler system. The engine also had full compression and fuel system tests, passing both with flying colors.