Each 2 psi of back pressure is estimated to cause a loss of how much engine horsepower?

The correct answer indicates that each 2 psi of back pressure is estimated to cause a loss of 4 horsepower from an engine. This relationship highlights the impact that exhaust system restrictions have on engine performance.

When back pressure increases due to obstructions or inefficiencies in the exhaust system, it forces the engine to work harder to expel exhaust gases. This additional effort can result in a significant decrease in overall horsepower. The engine's ability to breathe efficiently and expel exhaust gases is crucial for performance, and thus, maintaining optimal back pressure is important for preserving horsepower.

In practical terms, understanding this relationship helps technicians diagnose performance issues related to the exhaust system and underscores the importance of proper exhaust design and maintenance for optimal engine operation.