do someone knows how much % power will car loose , if have for example 11:1 mixure instead of 12.5:1 ??

is loses about in 5 bhp or more?

I kow that noone knows exactly, depends on 100 things, but rough messured

I have little popings from exhaust when I braking with engine...not bangs but constant poppings...I hope mixure is under 11.5