How to determine what exhaust I need?
 

There are so many exhaust options, how do I determine what exhaust I’m going to need?Custom 496 stroker motor puts out 570 hp 670 foot pounds of torque. I’m going to be redoing the air inlet and put a through transom exhaust with a captain‘s call switch to route the exhaust out into the water if it’s too loud.

Replacing my 7.4l it currently uses a wet exhaust system. Id prefer a wet system to keep the manifolds cool.

Stainless marine

What cam?? Stainless marine is a great exhaust, What you will deal with more given healthy numbers from a 496 is the possibility of reversion, a captains call could possibly increases that risk it really depends on the build of the motor. If your motor designer/builder is a good marine guy he should be able to tell you.

With those numbers I doubt you will be able to run silent choice. If you can swing it , gen3 stainless marine is hard to beat.

yup, and ask to have the dam put in if not standard. This helps even more against reversion.

Motor delivered today...

From the package...

. THE CAMSHAFT IS A NEW ELGIN INDUSTRIES E1143P AND WITH A TRUE CLOYES DOUBLE ROLLER CHAIN SET. THIS CAMSHAFT IS A HYDRAULIC LIFTER GRIND .576 LIFT 246 DURATION @.050 ON BOTH THE INTAKE AND EXHAUST AND IT IS GROUND ON 108 DEGREE LOBE SEPARATION

Sorry for the caps am using my phone,. I quickly and copied and pasted this from the description

Smarter guys will chime in, but I think 108 will be a problem with wet exhaust

Dry exhaust with no water even crossing the exhaust stream at the end. Has to be watercooled in an I/O application.

This type exhaust legal for your area ?

Dimly lit minds like mine wanna know how this got delivered ? Was this ordered as a I/O marine engine of course.

i live and boat in Wyoming. We have no exhaust laws for boats.

We run dry exhaust. Stainless marine.

it has been confirmed by dockhands at our local watering hole…we are the second loudest boat in the area.

Forgot to mention this is an I/O application.

makes sense, the cam is going to cause the motor to lope

So it sounds like through transom exhaust with a dam prevent water from getting back inside. I am a bit confused though, because it is an I/O it has to be water cooled, the water is sucked up to cool the motor and dumped into the exhaust to drain…..or so I thought??

you’ll need completely dry. Water cooled of course. And headsets.

so how is the water cycled then? I assumed it was dumped in the exhaust?? If this was a sports car I’d know where to go, haven’t been into boating for very long…and the boating season where I live lasts for about 3.5 months is all.

Dry manifolds and pipes still can have water jackets. The cooling water will just dump outside of the exhaust, not into it. Expensive but sounds sick.

Typical "wet" marine exhaust has the cooling jacket water being dumped in with the exhaust gas at some point before the exhaust leaves the boat.

With dry marine exhaust, the water doesn't go from the cooling jacket of the exhaust, into the exhaust gas stream and out the tailpipe.

The water is dumped overboard via a separate hose that is usually plumbed from the cooling jacket, to a through hull fitting.

Dry exhaust is still water jacketed as wet exhaust. Don't let the term dry confuse you. The difference being no water enters the exhaust stream as wet exhaust does.
There's many variation also as to where water can get introduced if it does so to speak in a dry exhaust.

Thanks everybody I appreciate the knowledge.

Our dry exhaust…


https://cimg3.ibsrv.net/gimg/www.off...15555d793.jpeg
https://cimg4.ibsrv.net/gimg/www.off...a40031f62.jpeg

What is that pipe that’s inside the exhaust. If This is a car I’d say that’s a screw in muffler type silencer to decrease the sound, but I doubt that’s what it is on the boat.
Sure is pretty looking!

That’s where the water exits

It's called dry to the tip exhaust. The pipe is double walled and that little pipe is connected to the inner liner of the jacketed pipe. So that whole pipe is full of water and exits at the end.

👍🏼
Now I understand, however, doesn’t that jacketed pipe cause a flow restriction? If it idoes all you have to do is go up and the diameter of your exhaust pipe. Or, does it cause enough back pressure to generate quicker spooling for turbo charged applications? Am I reading way too much into this? Definitely won’t ever turbo charge the boat, supercharger maybe in the future, but not for a long time.

Yes, lol

Over think much…holy sh!t Batman

Your going to be this loud....

excellent! Dang loud.

i appreciate everybody’s input on this. Helps me a lot.

This

Don’t forget your blinker fluid!!

I went a little different route, when I extended my tails, I cut the end where the water traditionally enters, and just spliced it on the end of my extension tubing

https://cimg4.ibsrv.net/gimg/www.off...7c9b2a7604.jpg
https://cimg1.ibsrv.net/gimg/www.off...bc0043e06f.jpg