Came across this picture of a Boxer. It has open throttle bodies (is that what they are called?) I think the engine lid above it has slats in it. Just curious to know, how does it get air in and what stops rain and debris getting into them? Sorry if it sounds like a stupid question, but just curious. Image Unavailable, Please Login Image Unavailable, Please Login
Early thinking was to have less restriction against air flow (no filter) and just have the chicken wire to keep out the big chunks. In most cases I have dealt with the engine came to an abrupt end due to rubber chunks flying off the slicks and holding a valve open once ingested. Race engines run this way had a life expectancy of a few hundred miles IF they had no off track excursions. Later flow bench testing showed the chicken wire to be quite restrictive by itself
Velocity stacks to keep crap from falling in. Air come in when the vacuum created by the decending piston reaches the top of the velocity stack. Air is pushed by the atmospheric pressure (14.7 PSI). These were thought to be "the thing" back in the mid-late 1960s. In the mid 1970s F1 guys figured out that a big air box over the velocity stacks gave better air flow management--including the snorkle facing forward.
This only works if the engine is fuel injected and can alter itself for the extra air pressure, otherwise it will lean out. For a carbed engine it is still best to allow the whole engine bay to be the airbox. Pete ps: Somebody needs to clean those poor old dirty carbs on this boxer.
They make lil' foam socks for them that help a little...I agree they are for people that like to hold their pistons and bearings in their hand far too often...
