Engine air intake size...

[firepiper]

I repowered from twin sb 350 ci to 454's. My engine 'vent's on side of boat are 3x17, 57 sq/inches. Engine room gets pretty warm. I'm wondering if I need more air....any thoughts?

 

[Reverend Bob]

Cooler air is much denser and holds more oxygen per volume than warm air. So, yes you might work up a better way of venting hot air, and increasing the flow of cool air.

More oxygen translates to more power.

 

[fastjeff]

Plenty big enough. I'll bet your boat had optional engines of that size when ordered.

Jeff

 

[makomark]

Crusader (& most other OEMs) will tell you that you need to supply ~ 700 CFM, per engine, with less than a 2" (H2O) pressure drop. They will also tell you the ventilation system needs to provide enough flow to keep the engine compartment temp below 150 deg F. The latter is usually the driving requirement and typically requires forced ventilation.

 

[bulletine]

They will also tell you the ventilation system needs to provide enough flow to keep the engine compartment temp below 150 deg F. The latter is usually the driving requirement and typically requires forced ventilation.

This is very interesting, I have an extra outdoor thermometer I think I will install in the engine room. A great experiment and thanks I am
learning all the time

 

[Reverend Bob]

I repowered from twin sb 350 ci to 454's. My engine 'vent's on side of boat are 3x17, 57 sq/inches. Engine room gets pretty warm. I'm wondering if I need more air....any thoughts?

I think that actually works out to 51 square inches per vent.

 

[firepiper]

oops, Rev Bob, you're right. Duh! Thanks