Change in engine power as altitude increases in GA planes

[DementedCorn327]

@Deacon8tor

Wasn’t there a recent change of the mixture physics in MSFS?

Yes, in SU13 they have added new parameters for piston engine:
Continuing the discussion from Release Notes - Sim Update 13 [1.34.16.0] Available Now:

@SeedyL3205

Added use_intake_density_on_mixture, density_to_boost_table, mixture_lever_to_ratio_table, mixture_ratio_to_engine_efficiency_table, use_volumetric_fuel_flow, and rpm_on_volumetric_efficiency parameters to piston engine cfg to address turbo, mixture, and fuel flow issues

And I agree some planes maybe need some tweaks to use efficiently those new parameters.
Could you perform the same test with the stock C172 G1000 ?, I’ll also do that on my side. (I don’t have the C172 classic, just the C172 G1000, do they have different engine ?)
But saying that mixture is not working at all (for all GA planes) or just seeing a difference in RPM by pulling the mixture lever all the way down is incorrect, something is incorrectly setup there.