benjen

I have thought about this off and on and finally decided even if it is viewed as a dumb question I am going to ask it anyway. I am sick of all the exhaust leaks and injured engines as a result. Why can't we run dry, normal automotive headers and tail pipes in a boat. Is it a coast guard requirement to have wet exhaust or is it just something that has always been done this way? Yes, they will get hot. But, Corvettes and tons of cars with glass noses run headers and don't burn to the ground from the excessive heat. I know the engine compartment in a car is open on the bottom and certainly helps with heat dissapation. However, you can also run the header wrap that will reduce the heat considerably...........probably equal to the cooling gained by the more open automotive engine compartment. Also, remember when we shut off the engines and the water stops flowing the headers gain tons of heat. Again, we aren't melting fiberglass while we stop for lunch. So, there is the question. Let me hear from you guys.

Wally

iTrader: (1)

you can run a dry exhaust but it would have to be wrapped and possibly also have some sort of shielding...i have seen commercial vessels with dry exhaust but with the wrapping you could keep your hand on it and it would be barely warm.....also with the tight spaces on boats the Coasties do have regulation on how much spacing must be between the exhaust and any flammable stuff...also keep in mind that a corvette or any other car barely gets over 2500rpm when running around unless you are getting on it...and how long does one stay in the gas on a car? Where on a boat you are full tilt for possibly many minutes on end so the heat generated is enormous compared to a car.

SB

iTrader: (1)

It only takes 30hp or so for a Corvette to cruise well over 60mph.

Mr Maine

Also, if a corvette were to catch on fire, you can simply walk away from it. Not as easy in a boat.
There is a tremendous amount of heat through the exhaust under heavy load and the tight engine compartment would be dangerously hot. Even if you wrapped them it still needs to go through the wood/glass transom.
They do have them on open over the transom exhaust on drag boats.

dereknkathy

The engine compartment is an enclosed box very little bigger than the engine. The commercial boats have very large engine rooms and LOTS of ventilation. Or engines mounted topside. An open engine perf boat could get away with it, sort-of. And even if it wasn't dangerous, think how the boat would run with that intake air temp.

Crude Intentions

iTrader: (1)

Gasoline can autoignite in the upper 400s. An enclosed engine bay with auto headers would likely get to that temp on hard runs. No bueno

sutphen 30

and if the engine comp got that hot,,the engine would run like schit.

benjen

I guess you guys are correct. As I think about it now if you watch a hard dyno pull the headers turn cherry red...........serious heat for sure! So, we will just keep fixing the leaks I guess. Thanks for the feedback.