Let me clarify some misconceptions for good..
HOBC is not suitable for small cars. Recommended for normal road cars (non high performance/sports engines) is 90 Octane no.
PSO/Attock has fuel 87-89 RON
Shell/Total has 91 RON
HOBC is 93-95 RON at various pumps
So if u wonna run "Clean" engine internals.. go for total/shell fuel.
If u want to get injectors cleaned please go to a mechanic and ask him to clean them, lol.. using HOBC is not a way to clan injectors!
Using HOBC in normal engines can have adverse effects such as engine sounding loud n dry.. engine heats up more and it can be tough on engine seals.
I have seen a Cruiser V8 100% used on HOBC and boy o boy engine was NOT happy! Car idled too high, it had become very noisey and sounded like a truck! So if u think ur 660cc-V8 cars need high octane and that ur doing the car a favor? U r so wrong..
If u reeeeally wonna have HOBC, then use it in mixture. no more than 25% HOBC is enough. Yes higher octane no. means better mileage and less carbon. So go for Shell/Total regular petrol. But dont go crazy for HOBC.. its not that good for regular cars n engines.