Exhaust Manifolds & Headers Flashcards
6 cards from real Exhaust practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Exhaust Manifolds & Headers flashcards as text
What is the primary purpose of an exhaust manifold?
Answer: To collect exhaust gases from cylinders and route them to the exhaust pipe
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.
What material is most commonly used to manufacture OEM exhaust manifolds on passenger vehicles?
Answer: Cast iron
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.
What is the main advantage of aftermarket exhaust headers over stock exhaust manifolds?
Answer: They reduce exhaust back pressure and increase engine performance
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.
What is an 'equal-length header' designed to achieve?
Answer: Identical exhaust pulse timing from each cylinder for better scavenging
Equal-length headers ensure each cylinder's exhaust pulse travels the same distance to the collector, improving exhaust scavenging and maximizing power output.
What typically causes an exhaust manifold to crack?
Answer: Repeated thermal cycling causing metal fatigue
Exhaust manifolds expand and contract with every heat cycle; over time, this thermal stress causes metal fatigue and cracking, especially at high-stress points.
A 4-2-1 header configuration refers to what?
Answer: Four primary tubes, two secondary tubes, one collector
A 4-2-1 header has four primary tubes that merge into two secondary tubes, which then merge into a single collector, providing a balance of low-end torque and high-RPM power.