DB605A critical height

[the_emperor]

Hey there,
according to manuals the critical height for the DB605A engine is rated at 5.7km in climb and 6.4-6.6km in level flight for Steig-und Kampfleistung (1.3ata/2600rpm)
and the DB605AM engines critical height in Climb at 1.7ata/2800rpm is ratet at 4.0km. Unfortunately my engines in the 109 start to loose boost in climb at around 3000m with the DB605 at 1.3ata/2600rpm  and around 1000m with the DB605AM at 1.7ata/2800rpm
So my questions: is there a special engine setting I am missing except pushing the throttle to the desired ata/rpm setting?  I am not that familiar with the 109 models since I mostly fly Spitfire.
So far only tested on summer maps (should there be a difference between summer and winter for the engines critical altitude?).
Thanks for our help and happy holidays.
Cheers

Edited April 11, 2020 by the_emperor