If you did; unlikely, manage to increase the power you will decrease the reliability
. Yanmar designed the intake for a reason. If they could have got one more horsepower by redesigning it they would. I have a 2GM20
and I guess it's intake is similar.
Your 80 amp alternator
(I have the same Hitachi one from a 3GM30
) is absorbing 1.5 horsepower. There are 746 watts to 1 hp. Watts is volts X amps. So 80 amps X 14 volts divided by 746 = 1.5 HP round figures. You can calculate what your blower might absorb the same way. Your 6 amp blower absorbs around .1 of a horsepower. How is one tenth of a horsepower boost going to make your 30 (27 HP) any more powerful?
What you are proposing is supercharging. When an engine is supercharged it is normal to decrease the measured compression ratio as supercharging will increase the effective compression ratio. That is because the volumetric efficiency is increased. But with a diesel you would also need to inject more fuel to obtain more power.
Boy racers often install a pretty looking alloy cold air intake with a less restrictive air filter in their cars. That's not a bad thing to do. My Nissan
V6 has that as standard factory designed in black plastic as do many other cars these days. There are also after market electric
blowers designed for the intake, as you are suggesting. But all those things are for gasoline engined cars. All I suspect the add on electric
blowers do is to create more turbulence and mix the atomised fuel better with the air. But our diesels are only sucking in air as the fuel is injected in each cylinder during the power stroke.
I've installed an electric fan (wired to the start key) in my Yanmar engine box mainly to cool the alternator which has a smart regulator
. It's a large computer cooling
type of fan. At the same time it supplies cooler air to the intake which is not a bad thing. Though its improvement to actual power is doubtful. A change in the atmospheric barometric pressure probably makes more difference.
What truck racers ( Kenworth etc tractor units racing
on a circuit) do to increase the power of their turbo supercharged trucks (exhaust driven) is to modify or replace the injector pumps to squirt more fuel in their engines. They tell me it drastically decreases the life of the engines but increases the power. They pour out black smoke when they accelerate with the turbo lagging behind the fuel supplied.
I suspect Yanmar have designed their air intake to be able to supply the amount of air required by the capacity of the fuel injection pump. If you did manage to supply more air to your cylinders you would also need to inject more fuel to obtain more power.
I would say "yes" to ventilating your engine compartment by better supplying cooler air.
One more thing. Look at your exhaust
system for any restrictions. Is your system (1,1/2" ?) all the way including the water lock and final outlet. I've often seen boats where a bit of plastic pipe extension is jammed in an already restrictive cast bronze exhaust
skin fitting. I found my original plastic water lock had 1,1/2" in and out but the hole inside the inlet was only 1". I replaced it with a larger water lock. Improvement to your exhaust system is the best area to obtain the factory power rating. A thin wall SS skin fitting is best as there is little restriction. Don't forget the exhaust system has to carry cooling
water as well as exhaust gasses.
Turbo charged marine diesel engines factory designed are a different story and enable an engine to have a better power weight ratio and they absolutely need a good exhaust system. Factory turbo engines are good but I think they add another potential problem area.
Old piston engined aircraft such as the Super Constalation had superchargers plus turbo chargers to maintain power at high altitudes.