Exhaust Exhaust Manifolds & Headers

Question 1

What is the primary purpose of an exhaust manifold?

Accepted Answer

To collect exhaust gases from cylinders and route them to the exhaust pipe

Answer

The exhaust manifold collects burned exhaust gases from each cylinder and channels them into a single exhaust pipe leading to the rest of the exhaust system.

Question 2

What material is most commonly used to manufacture OEM exhaust manifolds on passenger vehicles?

Accepted Answer

Cast iron

Answer

Cast iron is the most common OEM material for exhaust manifolds because it is inexpensive, durable, and handles the high thermal stress of exhaust temperatures well.

Question 3

What is the main advantage of aftermarket exhaust headers over stock exhaust manifolds?

Accepted Answer

They reduce exhaust back pressure and increase engine performance

Answer

Performance headers use equal-length tubes and smoother bends to reduce exhaust back pressure, allowing the engine to expel gases more efficiently and produce more power.

Question 4

What is an 'equal-length header' designed to achieve?

Accepted Answer

Identical exhaust pulse timing from each cylinder for better scavenging

Answer

Equal-length headers ensure each cylinder's exhaust pulse travels the same distance to the collector, improving exhaust scavenging and maximizing power output.

Question 5

What typically causes an exhaust manifold to crack?

Accepted Answer

Repeated thermal cycling causing metal fatigue

Answer

Exhaust manifolds expand and contract with every heat cycle; over time, this thermal stress causes metal fatigue and cracking, especially at high-stress points.

Exhaust Practice Test

Exhaust Practice Test

Exhaust Exhaust Manifolds & Headers