Miika.K

Hello and greetings from Finland!

I have a 360hp 454 motor with thru hull exhaust now, I`m planning to put revolution marine exhaust manifolds with dry risers in it, I`m going to lead the cooling water out from the exhaust tips or thru hull also...

I want to know is there going to be some heat problems if there is no water jacket in the risers? Do I burn my boat? Is there examples of these kind of assys somewhere?

- Miika

GTOFFSHORE

If it comes with dry risers they will have water in them. They just exit at the tip thru a dump.
Also if you are not running a big cam it's pretty useless. It will be really loud.

A.O. Razor

Welcome to OSO.

If you run dry to the tips, your exhaust needs to be fully water jacketed, from manifolds to the tips. You'll set your boat on fire if they are not. Hardin, CMI and others make dry exhaust systems. They won't as Poker said, give you much, if any performance gain on your mild 454. They will be friggin' loud.

Give Hardin or CMI a call, they can provide with what you need for a complete dry system.

http://www.hardin-marine.com/ 877-900-7278

http://www.custommarine.com/ 920-720-4225

Miika.K

So it will work if I don`t put waterjacketed risers, but I lead the cooling water in to the risers and the water will exit thru the exhaustpipes?

A.O. Razor

Do you have some pics of your risers and manifolds? Many risers on performance exhaust systems are water jacketed with a bung that connects a hose to another bung on the tail pipe, here it introduces the water into the exhaust. It can also introduce the water from the jacket internally into the tail pipe, where the riser and tail pipe connects. Some water jacketed risers have ports that match ports on the manifolds so there is no bung flowing water from one to the other, and then again uses one of the before mentioned methods to introduce water into the tailpipe. Some systems have a riser where the exhaust tube itself, fits around the cooling ports on the manifold, so the water is introduced into the exhaust internally between the manifold and riser connection. Lastly some systems introduces the water into the riser exhaust pipe via a bung that connects to the manifold. If you have the latter, yes you can just lead the water into the riser from your manifold and run a wet system.

Miika.K

Yeah, I`m doing some modifications to the motor also to add some HP... But I want to get it a little bit louder also, and I was thinking to put regular Revolution Marine exhaust manifold with waterjacket on it and then custom build riser without the waterjacket and the water will be injected to the exhaust pipe thru the riser... So I don`t have the riser yet, I`m planning how to do it... But I think there will be a heat problem so maybe the water jacketed riser is a must...

A.O. Razor

Get the Revolution risers. If you plan on upping the power, run the matching jacketed risers. A good reason to do this when upgrading is, that your risk of water reversion will be reduced because you introduce the water later in the system. They are cheap so no need trying to fix what is not broken or works, buy the matching risers.
Sound wise, there is not much difference whether the water is intoduced into the riser or just after. If you run straight wet tails, it is still going to be loud.

Miika.K

Now I`m running mercruiser casted iron exhaust manifolds, and I think they`re kind of muffled... But maybe there`s something wrong in my ears ...

A.O. Razor

They don't flow much, that is why they sound muffled. Have you purchased the Rev manifolds yet? If not, I personally find the EMI Thunder and IMCO Powerflow to be better systems, but of course that is somewhat of a subjective preference Give them a look-see.

What kind of mods are you planning?

Miika.K

The thing is that those revolution marine manifolds are very cheap compared to the quality... I`ve heard that u can`t beat the quality compared to the price on them... I`m planning to change camshaft & cams & pistons... aluminium edelbrock (don`t remember the type of it) intake manifold I have already...