Carb icing is caused by the pressure drop in the venturi
& the simultaneous evaporation of the fuel.  I doubt that the
fuel evap alone will cause any ice, and there is no significant
pressure drop in the straight manifold.

Bill
Long EZ builder & pilot
mechanical engineer

Jeff Spitzer wrote:

Yes and no.  The situation is definately worse in the carb.  But we would
regularly ice up the *outside* of our intake pipes on the dyno at Moller
when we were injecting at the inlet end.  The math is rather simple.  Just
use the heat of vaporization of the fuel and F/A ratio.  I did this once a
long time ago and decided that indeed it is easy to pull enough heat to
form ice.  BTW, I NEVER saw ice on the inside of the tubes.

Jeff Spitzer

We could use a little ice in the engine compartment to cool things off.
Did the engine make more power Jeff with the injectors out there?
Higher charge density?

We could wrap copper tubing around the intake tubes and use
it to cool the oil. 

Paul Lamar

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