Been using RON 95 on my 2.0 FL since Day 1. My car just celebrated her 1st BD. No problems with knocking. Nowadays it is hard to find a car without a knock sensor anyways...
The biggest problem with using a low RON fuel is the loss of power, especially during hot afternoons or if the engine is clogged and not in tip top shape. Knocking can be induced not only due to compression ratio but external factors like underhood temperatures, air density and engine efficiency among others. If you find that your car is sluggish during afternoon runs and appreciably more powerful at night, that means your ECU is holding back the engine in the afternoon to keep temps in check and to prevent knocking. Changing up to a higher RON fuel will lessen the impact.
Here's how the knock sensor works. It is supposed to measure and detect imminent pre=detonation before it happens, and sends the data to the on-board ECU. The ignition timing advance on modern cars with EFI is fully regulated by the ECU and operates on a closed loop system, relying on data from various sensors from the intake all the way to the exhaust.
Ignition advance is dynamically controlled based on throttle input, IOW as you step on the pedal, as the revs climb the ignition is advanced more and more to compensate for the faster cycle between intake and exhaust strokes. The CVVT system works in conjunction with ignition advance to deliver optimum fuel mixture on demand. Unless the knock sensor is damaged, there is no reason why RON 95 cannot be used in a high compression modern engine with fully controlled engine management (knock sensor and CVVT).
Having said that, knock sensors do have a pre-set tolerance, i.e., if you use a fuel that has a very low RON rating like 88 (example), then knocking could still happen as the engine and ECU were not designed to operate below a certain threshold.
But to sum it all up, I believe there is no harm in using RON95 in the Forte.
Cheers
Thanks for the Info Bro. It really eases my concern about the issue of RON95 for Kia Forte.