Chinese Su-27s are old, so lets neglect that, but their Su-30s mostly have N-001E and N-001VEP radars which are slotted array radars with an air-air range of 150km for 5m2 target, while Su-30MKI has N-011M BARS PESA radar which has an air-air range of 140km for a Mig-29 sized target(said to be 5m2), 10km less. However that's not the full story.
As always we have to read the fine print. The range of a radar even when given with its accompanying RCS does not tell the whole story. The 150km range comes with a 'but' clause. N-001 radar's indeed has a range of 150km for 5m2 range but for detection probability of only 50%. Which means if there is a fighter at 150km with a RCS of 5m2 then the N-001 radar may detect it with only a 50% chance. It's a 50-50 situation. So in order to get a 100% probability the range will obviously reduce. But with BARS, the probability of detection is 100% for 140km for 5m2.
And ofcourse, there is the TVC for the MKI. And also the canards. Unlike the TVC, canards has one drawback which is it reduces the speed down to 1.9 Mach from the usual 2.0 Mach for canard-less Su-30MKK. Also the popular misconception that canards was mainly put in to increase maneuverability. Yes, the canards does increase maneuverability no doubt about that, but the main reason why it was installed was not because of maneuverability considerations but because to stabilize the Center of Gravity & Center of Pressure of the aircraft which got screwed up due to installing the heavy BARS radar which weighs 600kgs compared to the 250-300kgs odd radar on baseline Su-27.
