Assalam o Alicom Guyz,
My Civic and Alto are CNG, in that there's no blocking of Air intake..
But in my City i-DSI M/T when i got it installed the cng installer didn't blocked the air and said it will choke your car engine.. the pick wasn't good it was worst, I was like I did mistake in buying City i-DSI, afterward from other CNG mechanic he blocked the intake 70% or somewhat like that and adjust the nut for perfect mixture.. beleive me city pick has gone good and so consumption... But I'm still confused if I'm choking my car while my city intake is 70% blocked!
I have driven mehran on cng and It pick is good I don't think Mehran need air intake blockage!