It sounds like you are trying to quiet down the engine and get a little more power while you are at it. Unfortunately, I don't think it will make a significant different in the end although you could do a pretty simple test and check it.
The sound in a diesel
comes from many places, one of which is the air intake. On a naturally aspirated engine like you have, relatively little sound comes from the air intake, a lot more comes from the head
, block and the exhaust. Even extending the air intake won't help that much since the actual pipe will transmit sound so it would need to have insulation
The reason that people try to use cold air intakes is that the air is denser so they can get more of it into the cylinder at a given pressure. This is a really big deal for very high performance engines where they are trying to force as much air into the cylinder as possible so that they can burn the most fuel
possible. Unlike gassers, diesels are fuel
throttled not air throttled so unless you are overfueling, it won't make a difference.
Two things to worry about
: Make sure that you are not causing a restriction to the intake, it will make everything worse rather than better. Also, make sure that you don't put the intake somewhere that a rogue wave
could submerse it.