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Heated Intake Manifolds

567 Views 1 Reply 1 Participant Last post by  dorfs
A question has come up in my emails with a colleague on the board about the purpose of the water heated intake manifolds? It seems to me that water heating of them should aid vaporization in cold climates, like Grand Forks, ND or maybe they were just added to handle some pollution concerns. Appreciate some clarity on the purpose and adv/disadvantages of water heated intake manifolds? Thanks

CJ7 258
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It is called E.F.E. or early fuel evaporation. It does just what you said it does. Some systems used water, others used an electric grid under the carb, and others used exhaust gases (heat risers). Injected engines don't really need it, as it uses the valve for atomization and there is no fuel in the intake plenum.
One other note, on the early GM's that had the flat cam problems, it was caused by the heat riser. The vacuum switch in the t-stat housing that controlled the heat riser was out of calibration. It left the heat riser on all the time, and the block didn't expand as fast as the liters did. Too tight of a hole, flat cam!

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