109 e4 performance

[Crumpp]

Extrapolating it would be at 990 mmHg at 0m.

You are confusing manifold pressure with atmospheric pressure, I believe.

If you read the report, it says nothing about any of the data being converted to standard conditions. Therefore it is raw data for the atmospheric conditions given.

The results obtained in the Center during the first tests seem to
match well with the German manual, with regards to the level flight
speeds and the fuel consumption. Nevertheless, during the level flight
testing done under 5000 meters (external temperature = +6°C on ground
and -17°C at 5000 m.)

http://kurfurst.org/Performance_test...formanceT.html

When you convert the performance to standard conditions, the results will be faster than the raw numbers in the report.