Matt Thio
02-23-2003, 07:32 PM
On the topic of calculating the secondary header lengths of a 4-2-1 conifiguration exhaust manifold, i'm interesting in hearing other teams' experiences.
1. Firing order is 1243 like an F4
2. Cylinder 1's EVOs
3. Wave travels at vel. = c in gas at T(exh)
4. Wave of rarefaction is reflected at 1st col.
5. 2 +tive waves of diminished amplitude are transmitted to cylinder 4 and the secondary collector. At the secondary collector another wave of rarefaction is reflected back towards cylinders 1 & 4, and a further diminished positive wave is transmitted towards the junction of cylinders 2 and 3 where it may interfere with the scavenging process of cylinder 2 & 3.
Is the aim of designing the secondary lengths to delay the onset of the positive pulse reaching the exhaust valve of cylinders 2 and 3 until the exhaust valve is closed at cylinders 2 and 3 at a specified RPM?
1. Firing order is 1243 like an F4
2. Cylinder 1's EVOs
3. Wave travels at vel. = c in gas at T(exh)
4. Wave of rarefaction is reflected at 1st col.
5. 2 +tive waves of diminished amplitude are transmitted to cylinder 4 and the secondary collector. At the secondary collector another wave of rarefaction is reflected back towards cylinders 1 & 4, and a further diminished positive wave is transmitted towards the junction of cylinders 2 and 3 where it may interfere with the scavenging process of cylinder 2 & 3.
Is the aim of designing the secondary lengths to delay the onset of the positive pulse reaching the exhaust valve of cylinders 2 and 3 until the exhaust valve is closed at cylinders 2 and 3 at a specified RPM?