Chapter 6 Engine Types and Classifi cations 145 Copyright by Goodheart-Willcox Co., Inc. (SOHC) (DOHC) Figure 6-40. Compare the single overhead camshaft engine on the left with the dual overhead camshaft engine on the right. How many differences can you find? (Saturn) Turbo wastegate Exhaust out Turbine Compressor Air in Air under pressure Intake manifold Fuel supply Figure 6-41. This is a turbocharged, inline engine that uses a wastegate to limit boost pressure. Note the airflow. (Audi)