If wanna save that RM0.20, can put a piggy back or do ecu/pcm reflash
Alternatively, can put this water/methanol system or can simply add about 150ml 2T for a full 60L tank. Modern cars have the knock sensor and the signal will tell the ECU/PCM to adjust the ignition timing. 97 to 95 will be fine. If continuously knocking, the check engine light will tell you, else the engine sound
. No need to be panic. As long as don't ram the car till red line, most probably knocking can be prevent. For those turbo/supercharged or NOS or lean tuned car, come on, you all have all the money to play car but cannot afford the RM2 fuel price? The new Saga may be the best solution besides kapchai.
For fuel injection car, normally will have O2 sensor which meant for measure the oxygen contains in the exhaust gas and the signal back to ECU/PCM for adjusting the air fuel ratio according to the map (front O2, at exhaust manifold). If the sensor is good and no parts failure, the AF will be good and most likely carbon will be minimized. For certain cars (especially newer car), the system has more advance system, which usually will inject more fuel to cool down the engine in order to prevent knocking, aka detonation. Because they are designed to run as lean as possible in order to pass those euro4 or some other standards. But also need to increase the compression ratio to gain the max horse power for better sales. Injecting more fuel on higher engine temperature is just their tricks. As there is a loop hole in the system, where the emission standards are usually based on the capacity of the engine, that's why today's cibic type R has to go to 2L in stead of something nearer to their famous B16 series. If wanna maintain the same capacity, then will be like c-class, where a compressor is found in the engine bay (selling cost will be greatly raised). If the car is healthy, it won't generate extra carbon deposits by using 2 different ron rating fuel. For extra info, typical O2 sensor working temperature is above 600 degree celcius. Warm up your car will let the sensor send back accurate signal and lesser carbon will be produced. I won't surprise if they use some electrical thing to warm up the sensor in the future, just like the MAF sensor which can be reach 1000 degree celcius before you crank start the car (in 1-3 seconds)(that's why you can find in the car operating manual saying that need to wait for the light to turn off before crank. But usually the airbag initializing takes longer).
For carburetor car, you can always send it for a dyno tune. Adjust the carb jet(s) setting for optimum output with the fuel you wanna use. Anyway I think RON95 is the best available in the public market for that era
Using RON97 is a waste only if just pump into a old tech car engine and drive away like that. Proper tuning can actually lean out the AF for full range of RPM and the result will be less drops needed for the same complete stroke. But too lean (15:1 and above) will results more spark plug wear & tear. I'm lazy to calculate which is saving more for short or long term. I just know, if you beh tahan but refuse to change your lifestyle, you are going into a dead end. Face, urges and etc sometimes worth more than life for some people.
I leave the light weight and tayar sotong for others to talk about
