@qasim_ali_qureshi
Economy vehicles mostly,as name suggests, are not designed to be used on high octane rated feul as feul has higher ph and damages your carburator plastic/rubber seals.
Mixing High octane(say having 97 octane with petrol having 87 octane will give you an octane of 93 at 50/50 mixing ratio)reduces the octane and thus reduces chance of damage to seals.Best recommended & easiest setup for all economy vehicles in Pakistan keeping in view feul cost and engine performance:-
1. Rs.100/- Hi Octane,Fill the rest with Premier(When feul tank is above Half)(Octane of 90 or above achieved)
2. Rs.200/- Hi Octane,Fill the rest with Premier(When feul tank is below Half)(Octane of 90 or above achieved)
For vehicles with EFI technology,most of them are equipped with feul coder which functions to inform ECM of vehicle of type of feul being used.The vehicle then adapts settings for that specific type of feul and ensures maximum performance and economy.If the coder setting is wrong,it can lead to engine damage.For example,Daewoo Racer 1993 has feul coder which can be set for two types of feul:-
1. Petrol having Octane greater than 92
2. Petrol having Octane lessor than 92
NOTE:- Using vehicle on feul having octane greater than 92 with option 2
does not cause any engine damage.Only better mileage & performance is possible which is not achievable at this setting.Option 2
is used for pakistan due to the present condition and quality of feul.Option1
can only be used in Pakistan,if feul type High Octane being used.In other countries,Regular feul used has less impurities and octane higher than 91 thus option 1
is mostly used.
Pakistan Premier plus has an octane of 87 according to officials but keeping in view mixing and quality standards it must be around 85.Old super had an octane of 82 according to officials but was found to be 79 after testing it thus would result in excessive knocking of vehicle engine on sudden acceleration or steep hills.
Confirm via mechanic if your vehicle has a feul coder as almost all daewoo users have changed it to option 2
(Company setting is 1
).