A __________ collector improves low-to mid-range power.

• A. Longer length
• B. Shorter length
• C. Larger diameter
• D. Heavier weight

Answer: (A)

Longer collector length tunes the exhaust pulses to improve scavenging at lower engine speeds, which boosts torque in the low-to-mid RPM range. By giving the exhaust pulses more distance and time before they merge, the pressure waves help push exhaust gases out and draw in fresh charge when the engine is spinning slower, enhancing power where you normally operate in everyday driving or racing before redline. If the collector were shorter, the beneficial timing shifts toward higher RPMs, so the low-to-mid range wouldn’t gain as much. A larger diameter can reduce backpressure but lowers exhaust gas velocity, which can weaken scavenging at low speeds, and heavier weight doesn’t directly increase power.