[JFP in PA]

Originally Posted by Jager

Yep.
http://986forum.com/forums/performance-technical-chat/9671-finally-dyno-charts-de-snorked-986s-6.html

Perhaps the most interesting, and as well as humorus point is that it was one run, under questionable conditions (a mobile dyno setup), and even many of the posters in this long thread questioned the validity of the data. One poster summed the data perfectly:

"Dyno results can be funny and not always verifiable or repeatable. The Lister must admit this if he's the kind of engineer, he seems to be.

So many variables must be exactly the same on each run for any results to be meaningful, especially since you're claiming a very small % gain of overall power (1.9%). Some, but not all include: Ambient Temp, Barometric pressure, Fuel flow, Octane, Alternator Output, each line of code in the DME operating w/o fault on each run, Engine Temp, Tranny Temp, Bearing Temp, and on and on.

For example, an Alternator (whose power draw is variable and not constant) alone can draw as much as 4-30 crank HP because of the inefficiencies in a Belt & Pulley system, so if it was filling demand on the 1st run, but not the 2nd, this alone could account for the variance seen.

The best method is to do multiple runs exactly duplicating the conditions of all previous runs and then averaging the results. Then, you reverse it, put the snorkel back on and see if you consistently achieve the previous Baseline numbers over an average of multiple runs. If these results aren't duplicated to within a pretty narrow degree, there is some variable not being accounted for.

Just because you get a graph from a single run which supports your theory, isn't in, and of, itself proof of anything..."

Rule number one on dyno data: If it isn't reproducible, it isn't..............