I'm installing one of the AFP fuel injection systems in my IO-360B2B powered RV-8A. I will be based in damp Southern Oregon where we do have frequent icing potential during the winter and early spring months.
I'm using Van's Filtered Airbox (FAB) to direct and filter air before it reaches the Airflow Performance fuel servo. I know I'm are not suppose to get icing with fuel injection system and therefore do not need alternate heated air (a.k.a. carb heat) before the filter. But the AFP fuel servo has a large butterfly valve serving to control mixture. Isn't the lower pressure/higher velocity around the butterfly valve one of the two causes of icing in carbs? Obviously there's no cooling from fuel evaporating in the AFP fuel servo so that doesn't contribute to an icing potential. I am also thinking that an alternate air source of heated air would reduce the build up of ice on the air filter itself.
Is there any benefit to having an alternate, slightly heated, air source for use with the AFP fuel servo? Or would there be any harm, other than slightly reduced engine performance, in having a slightly heated alternate air source? I already have installed the unfiltered alternate air source "gate" in the FAB for emergencies.
I would appreciate thoughts on the wisdom of adding a "carb heat" alternate air source for use in this setup.
Albert Thomas
N880AT
RV-8A QB
(FWF & wiring)
I'm using Van's Filtered Airbox (FAB) to direct and filter air before it reaches the Airflow Performance fuel servo. I know I'm are not suppose to get icing with fuel injection system and therefore do not need alternate heated air (a.k.a. carb heat) before the filter. But the AFP fuel servo has a large butterfly valve serving to control mixture. Isn't the lower pressure/higher velocity around the butterfly valve one of the two causes of icing in carbs? Obviously there's no cooling from fuel evaporating in the AFP fuel servo so that doesn't contribute to an icing potential. I am also thinking that an alternate air source of heated air would reduce the build up of ice on the air filter itself.
Is there any benefit to having an alternate, slightly heated, air source for use with the AFP fuel servo? Or would there be any harm, other than slightly reduced engine performance, in having a slightly heated alternate air source? I already have installed the unfiltered alternate air source "gate" in the FAB for emergencies.
I would appreciate thoughts on the wisdom of adding a "carb heat" alternate air source for use in this setup.
Albert Thomas
N880AT
RV-8A QB
(FWF & wiring)