Larry A Hoy wrote:
> get a question I have answered. Can anyone tell me the difference
> between a dual plane and a single plane intake manifold? I have no clue.
Larry:
The dual plane manifold has two sets of intake tracts sandwiched
one on top of the other. The smaller bore tract connects to the primary
side of the carb. The larger bore connects to the secondary. When
running under light load, only the primary of the carb. is operating.
The intake tract being a small diameter keeps the intake charge flowing
at high speed which helps distribution and keeps the fuel atomised. In
theory, the smaller intake tract will increase low load drivability.
The combined bore of the prim. and sec. tracts can in theory be larger
allowing more flow at the top end whilst retaining drivability at the
low end. One drawback is that the maximum bore is restricted by the
metal between the two tracts, but on our small bore engines this is not
a problem.
So in a nutshell. Low end drivability and economy requires a
small carb. with small intake tracts to maintain high speed intake flow.
High end power requires a big carb. with intake tracts matched to the
bore size to allow the maximum flow the engine can pump. The dual plane
manifold was designed to combine these features.
Hope this answers your question. Kelvin.
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