Reduces fuel consumption by up to 9% The Economax Engine Cooling System is proven to reduce fuel consumption by up to 9%. For HGVs covering considerable motorway mileage, fuel savings of 4 to 8% can be expected. Engines used in slow moving and semi-static environments, where ram air cooling is negligible, can achieve fuel savings in excess of 9%. Detailed corroborative data is available on request.