Developed to avoid expensive repairs and parts replacements rac cataclean is a complete fuel system service in a bottle which improves fuel consumption and reduces smoke emissions by up to 60 catalytic converters are fitted in both petrol and diesel engines and easily become clogged or coated with carbon deposits leading to poor conversion of exhaust gases this leads to poor fuel consumption and higher emissions that could mean youll fail your mot as soon as you add cataclean to your fu