Not Ranked
Doug,
It is most important that the standard correction factors be applied when doing any dyno testing as part of an engine development program.
Without the correction factors applied, you will have fairly significant variations in your numbers. Therefore, you would not know if a jetting change helped or hurt you. This applies to any change you make, headers, intake stacks, valve clearance, etc.
Also, dyno rooms can change temperature and humidity very rapidly during a run cycle. We always recorded the correction factors at each 500 rpm step and applied them to that part of the cycle. (Of course, these days, these things are recorded automatically and everything calculated by computer in real time. In my days the best we had was a HP calculator with reverse Polish notation. (You engineer folks will understand that one : )
With chassis dyno's, you open a whole can of worms when it comes to repeatabilty and serious engine development. I have seen as much as 22 ft lbs of torque difference on the same car from cold transmission and rear end fluids to warm fluids. (928 Porsche S4)
Those curves were really confusing as the driveline started to heat. The worst of was after the system was good and hot, you started losing engine performance due to heat soak.
Therefore, for serious engine development, an electric engine dyno is the only way to go. (Not a water brake, been there, done that, if incoming water pressure changes, you start getting woogie numbers)
For bragging rights, i would recommend a chassis dyno with a hot drivetrain and a cold engine.
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