I've read somewhere the AL-41 are the worst in stealth class of engines. No composites anywhere, only metal.
I would take this chance to clear some misconception on composites
You use composites for weight reduction mainly. For stealth, you still need to Coat it with absorbers as although composites may "have low RCS" They are -Penetrable- by EM wave thus your composite structure may not be visible to radar but -the insides- of your airframe will.
If one wish to reduce RCS with composite then the composite itself have to be designed to absorb or selectively picks what frequency it needs. This called as Radar Absorbent Structure (RAS)
as for the AL-41F1 Su-30's or SM2 used tho.. Stealth are not considered (But also other fighter engine in its class like GE F-132,129 or PW-100 or PW-220/229) therefore it lacks structures one could find in stealth fighter or dedicated engine like F-135 with Rear blocker or Su-57's frontal radar blocker.