For convert the default FS9 P&W-PT-6 turboprop engine in a Garrett TPE331.
It is a very unrealistic fly experience, i.e.: fly a Short’s Skyvan or a Turbocommander (Garrett engines equipped aircrafts) and has not the matching visuals (gauges) and audible pilot sensitive stimulus.
As many FS simmers knows, FS9 has modeled only one turboprop type: the Pratt & Whitney PT-6 engines but there are others aircrafts that uses the Garrett one, which differ mainly in the way they works.
The first uses two independent shafts, N1 and N2, one for the gas producer and the other for the power section.
The Garrett is a single shaft engine; the gas producer is in the same axis than the power section.
Technically the differences are: the P&W-PT-6 has an easier and fast start process and in counterpart the Garrett has a more proficient fuel consumption ratio.
But in the cockpit side are differences to. The main are: N2 becomes unnecessary. The P&W-PT-6 RPM gauges (Prop. and N2) becomes in a single ‘Percent RPM’ gauge in the Garrett.
In the power pedestal there are just Power Levers and Condition Levers (no fuel handling levers).