KNOWLEDGE IS POWER Steed Manifolds – Gated VS Non-Gated

A popular modification to those seeking higher performance out of their 5.9L or 6.7L common-rail Cummins is to switch the 2nd gen style manifold which mounts the turbo up high and between cylinders 3-4, using the split pulse or twin scroll effect that this setup provides to be able to drive much larger turbochargers than you normally would.

The twin scroll or split pulse effect is essentially keeping cylinders 1-3 and 4-6 exhaust pulses separate from each other all the way until the gasses actually reach the turbine. The fact that the pairing cylinders (1&6, 2&5 & 3&4) are on opposite ends of the manifold from each other means that at any given time there is always two separate exhaust pulses reaching the turbine at the exact time, almost as if you were driving a single turbo with two separate 3 cylinder engines.
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