Various Aircraft Specifications for a Video Game Mod

[tomo pauk]

Google tells me that Start Und Notsleigstung means "Start and Emergency Service." Since it has a three minute limit I guess that's more or less equivalent to War Emergency Power?

Yes and no?
War Emergency Power meant using the max RPM that was also used on Military Power, while also using over-boost. The 'Start- Und Notsleigstung' was probably equivalent of the early forms of Military Power, that was limited to 5 min on American engines. The 'Erhoehte Notleistung' was probably the true equivalent of WEP (or WER), when the BMW 801D was over-boosted beyond 1.42 ata (some time in mid-1943 and on). See here for example, also here.
When/if MW-50 was used, that was eventually called 'Sonder Notleistung' - Special Emergency power.

Start- Und Notsleigstung = Take-off and Emergency power.

On the DB 601 and 605 engines the highest ratings are generally listed as Höchtsleistung (High Performance) but those sometimes list a one minute limit which makes me question how often they were really used in combat. (Other times the limit is longer, and in other cases its unspecified which really makes me wonder what setting to use for my calculations with those engines.)

The 5-min limit was called differently in different time and on different engines, eg. on the DB 601A it was called 'Kurzleistung' - literally 'short-term power'.
The 1 min limit was sometimes found on data sheets for the DB 601N engine, seems it was so short because the 'bad' material used on fuel tanks of Bf 109s 'spoiled' the hi-oct C3 fuel reducing it's octane rating (info can be found at the 'The secret horsepower race' book). The max power setting was called 'Start und Notleistung' there; 30 min limit was called 'Steig- und Notleistung' - 'Climb and combat power'. Such terminology extended to the DB 601E, 603A and 605A, the 5-min stetting not always available due to reliability problems.

The DB 601A-1-min limit was just for take off - 'Abflugleistung'. Otherwise, the 5 min limit was the highest setting available for the pilot for combat (see here). The DB 601E and 605A were allowed for 5 min for the take off, once the engines were cleared for the 'Start- und Notleistung'; ie. it took about 6 months for the 601A, and ~15 months for the 605A for the clearance.