Be aware, though, that correction factors work best on naturally aspirated engines. Turbocharged engines don't lose power with altitude increases nearly as much as a naturally aspirated engine, so hot day/high altitude corrections will tend to overstate the hp obtained with a turbodiesel. That's why I quote uncorrected RWHP in my signature (not that it matters, since my truck is only set up as a trailer puller, not a dyno monster :{ )
Rusty