@pajerolover
4D55
Displacement - 2.3 L (2,346 cc)
Bore - 91.1 mm
Stroke - 90.0 mm
Fuel Type - Diesel
Non-Turbo
Power - 55 kW (75 PS) at 4,200 rpm
48 kW (65 hp) at 4,200 rpm
Torque - 147 N?m (108 lb?ft) at 2,500 rpm
137 N?m (101 lb?ft) at 2,000 rpm (SAE)
Engine type - Inline four-cylinder SOHC
Compression ratio - 21:1 (384 P.S.I. )
4D56
Displacement - 2.5 L (2,476 cc)
Bore - 91.1 mm
Stroke - 95.0 mm
Fuel type - Diesel
Valves per cylinder - 2
Non-Turbo
Power - 55 kW (74 hp) at 4,200 rpm
Torque - 142 N?m (105 lb?ft) at 2,500 rpm
Engine type - Inline 4-cylinder SOHC
Fuel system - Distribution type jet pump
Compression ratio - 21:1
TDI: Turbo Diesel Intercooler
There is not much difference hp if we compare non turbo 4D55 & 4D56 i.e. 10 hp
BUT
There is a Huge Difference of hp between Turbo 4D55(86hp) & 2nd Gen 4D56 TDi (134hp) i.e. 50hp gain if you go for Gen-2 4D56 TDi
and
If you go for Gen 3 4D56 TDi then you will gain 115 hp over your current engine non-turbo 4D55
Yes, you can swap 4D56 TDi bolt-on without any alteration!