Which term describes a header feature that merges flow before entering the collector?

• A. Formed
• B. Merge
• C. Tri-Y
• D. Double-slip

Answer: (B)

The concept being tested is how exhaust pulses from each cylinder are combined before they reach the collector. When the separate flow streams from the primaries join into a single path before entering the collector, that action is described by the term merge. Merging the flows helps preserve exhaust velocity, reduces backflow, and enhances scavenging, especially at the rpm range the header is tuned for. Other terms describe different header geometries (for example, Tri-Y routing, or designs that use two collectors or slip-fit paths), but they don’t specifically name the action of joining multiple flow streams into one before the collector. So the best fit for describing this feature is merge.