OK hahaha you guys are jokers....

ok let me put it straight... yes compression ratio affect the RON rating

see here

http://en.wikipedia.org/wiki/Compression_ratio

the calculation is


= cylinder bore (diameter)
= piston stroke length
= clearance volume. It is the volume of the combustion chamber (including head gasket). This is the minimum volume of the space at the end of the compression stroke, i.e. when the piston reaches top dead center (TDC). Because of the complex shape of this space, it is usually measured directly rather than calculated.

So this means a engine with compression ratio of 11.1 to 1 is safe to run on RON87

now lets look at our car Compression ratio

Honda City : Compression Ratio 10.4 (http://honda.com.my/model/overview/city/)
Honda Civic (NEW) : Compression Ratio 10.6(1.8l) 10.6(2.0l)
Honda Civic FD2r (Type-R) : Compression ratio 11.7 (Not RON 95 safe) USE RON97

Toyota Vios : Compression Ratio 10.5
Toyota FT86 : Compression Ratio 12.5 : 1 (not RON95 safe) USE RON 97

PROTON engine
Campro CFE engine : compression ratio : 8.9:1 to 10:1 (CPS retard the timing to 8.9 lowest)
Campro CPS engine : compression ratio 10:1

Myvi 1.3 : compression ratio 10.0:1

so we can now say it is safe to use RON95... wait wait how about old car before RON95... hehe

Proton Wira : Compression Ratio 9.2:1 (Safe for RON92)
Proton SAGA (The original SAGA) : Compression Ratio 9.5:1 (Safe for RON92)

remember when saga come out we only have RON91 and RON 92 the car need to be compatible with it... also that time Thailand only have RON88

so now who going to dispute the formula from wikipedia and our car will spoil in RON92...

MOST OF OUR CAR CAN RUN ON RON88 for GOODNESS SAKE!!! stop wasting money and let the rich waste money!!!