Well since we don't have a benchmark to classify an engine for 5th or 4th gen , I did a rough back of the envelop calculation for T:W ratio of Flanker,PAK-FA ,F-22 and F-35 fighter engine
1 The AL-31FP ,AL-31F and AL-31FN engine of Su-30MKI, J-10 and Su-34 generates a thrust of 12.5T and weighs 1520 kg which puts it in a T:W ratio of 8.2:1
2 The newer AL-31FM1 engine for newer Su-34 generates a thrust of 13.5T and weighs 1520 kg which places it in a T:W ratio of 8.8:1
3 The 117S ( AL-41F1A ) engine of Su-35 fame generates a thrust of 14.5 T weighs 1520 kg and has a T:W ratio of 9.5:1
4 Coming to PAK-FA 117 engine it weighs 1420 kg and generates a thrust of 15 T with T:W ratio of 10.5:1
Comparing similar 5th gen engine of American Fighter F-22 and F-35
5 The F119 engine of F-22 generates a thrust of 16T and weighs 1772 Kg and has a T:W ratio of 9:1
6 The F135 engine of F-35 generate a thrust of 19.5T and weighs 1701 Kg and has a T:W ratio of 11.4 :1
PAK-FA engine compares favorably with American 5th Gen Engine in T:W class and superior to F-22 engine while the F135 is the best engine in T:W class
Reference
1 source:
-31// > -
2 source:
FEDERAL STATE UNITARY ENTERPRISE «GAS-TURBINE ENGINEERING RESEARCH AND PRODUCTION CENTER «SALUT» | Production | AEROENGINES
3 source:
117 > -
4 source:
Saturn AL-31 - Wikipedia, the free encyclopedia
5 source:
Pratt & Whitney F119 - Wikipedia, the free encyclopedia
6 source:
http://en.wikipedia.org/wiki/Pratt_&_Whitney_F135