Not sure. The Warrior II is quite susceptible to turbulence which is buggy in MSFS at present. Try flying in the early morning just after sunrise and see if you still have the issue.
It would be engines.cfg in the section called [PISTON_ENGINE] where you can fiddle with horsepower, displacement, max rpm etc etc .
I think there is actually a mod kicking about that adds more performance to the Warrior, not sure. Have a search around.