Klimov RD-93:

JF-17 Thunder currently uses Klimov RD-93, a variant of RD-33 Engine. It has been reported that a Chinese engine Guizhou WS-13 Taishan is under development to replace RD-93 eventually.

RD-93 has been developed by Klimov Design Bureau in St. Petersburg. It is a variant of Klimov RD-33 Turbofan Engine which powers the MIG-29 Fulcrum. The most significant difference being the repositioning of the gearbox along the bottom of the engine casing.

RD-33 Specifications:
Thrust (Afterburner): 8300 kgf /18,260 lb
Thrust: 5040 kgf / 11,090 lb
Specific Fuel Consumption: 2.1 kg/kgf/Hr in afterburner, 0.77 military
Bypass Ratio: 0.46
Compressor Pressure Ratio: 21
Maximum Turbine Inlet Temperature: 1680 K
Service Life, hr: 4000
Length: 4.230m
Maximum Diameter: 1.040m
Mass: 1055 kg

One of the criticisms levelled against RD-93 has been its nature to emit black smoke, which makes it easier for the enemy pilot to spot the plane in close combat. This puts the pilot in inferior position during a dogfight. However, the emission of black smoke is not contineous as observed from JF-17's performance in Zhuahi and Izmir Airshow. The emission is observable for a short amount of time on certain levels of throttle. 

The sage of JF-17's engine is not without controversies. The contract between China and Russia over re-exporting the engines to Pakistan had ran into dispute due to Russian fears that JF-17 may compete against Mig-29 in export markets. Recently tho, the supply seems to be smooth without any problems.

Guizhou WS-13:

China is also working on an indigenous engine which has the potential to power the FC-1 in future. The engine is known as WS-13 Taishen. It is a turbofan engine developed by Guizhou Aircraft Industry Corporation. It was reported that JF-17 had been  tested with the engine in early 2010. 

WS-13 Specifications:
Maximum thrust: 51.2 kilonewtons (11,500 lbf) dry; 86.37 kilonewtons (19,420 lbf) with afterburner
Length: 4.14 metres (13.6 ft)
Diameter: 1.02 metres (3 ft 4 in)
Dry weight: 1,135 kilograms (2,500 lb)
Compressor: Two-spool 8-stage axial
Combustors: annular
Bypass ratio: 0.57:1
Turbine inlet temperature: 1650 K (1,377 °C (2,511 °F))
Thrust-to-weight ratio: 7.8

There have been reports of 100kN/22,450lbs thrust version under development.