[apexi]

There have been questions raised in some other posts regarding this topic but I'm wondering if there is any conclusive explanation into the following.

Sufficient time has now passed to gather a wide range of dyno results from different owners. The average range appears to be in between 325-335 RWHP. There are dyno results showing 350-370+RWHP that are OUTSIDE this average range, however anyone understanding the nature of dynos and how results can drastically change with parameters, conditions, strap down, etc can understand this variance. Pencil Geek has already demonstrated how going from 91 octane gas to 93+ makes a huge difference in HP results as well. Long story short, the dyno is primarily meant to be used as a before/after tuning tool that can give you consistent results and NOT as a tool for absolute measurements to compare "power" from one member's car in Cali to one in NY which can be almost random/near meaningless.

Furthermore, drivetrain losses are not static-state fixed % that can be used to derive engine HP from a dyno reading. But we of course all do it using the standard rule of thumb of 15%MT-20%AT. Based upon my experience, although drivetrain losses are a crude way of trying to estimate engine HP from a dyno, it normally isn't substantially far off from manufacturer's specs for MOST vehicles.

However, based upon the numerous dyno results out there, what I don't understand is whether our M3s have higher than normal drivetrain losses in the 20-22% range or perhaps the engines are slightly overrated? Or is there another explanation of why the M3 dyno results don't seem to correlate to engine specs using the standard rule of thumbs as most other vehicles do?