Yes, this is normal and one of the additional benefits of using Oxytane in any engine. Since any fuel contaminants are expelled when using Oxytane (mico air particles and water vapour) there will be less cavitation as the fuel delivered to the combustion chamber is denser. Also since Oxytane add lubricity to the fuel it also reduces the amount of turbulence when it is being combusted and thus reduces engine vibrations and noise. Further to this, it also reduces potential maintenance since a happier engine with less turbulence reduces the wear and tear over time.