Compression ratio is always > 1.ultimabasher said:Head to xbhp and read for R15. R15 has a compression ratio > 1. Any engine that has a compression ratio of more than 1 can make better use of premium petrol.
I too have R15. With normal petrol I get avg in 30's. With extra it crosses 40's and no I am not joking.
As WikedTA said, higher octane fuel only comes into play at a compression ratio of around 9 and above.