Re: 4-2-1 sau 4-1 ?
pe scurt This 4-2-1 type exhaust manifold has an advantage that the flow of the exhaust gas is more efficient compared with the 4-1 type exhaust manifold. However, in this exhaust manifold, because the first runner and the fourth runner face toward each other, if the length of the first and fourth runners is too short, an exhaust gas interference cannot be avoided in accordance with the igniting sequence (first cylinder→third cylinder→fourth cylinder→second cylinder). As with the 4-1 type exhaust manifold, the spacing between the runners is narrow where they join the confluence part, again resulting in thermal stress cracks.
Further, the 4-2-1 type exhaust manifold is more complicated in its structure compared with the 4-1 type exhaust manifold. Consequently, the manufacture is more difficult and the weight greater .
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Last edited by BC-20-LET; 18-06-09 at 23:34.
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