Dry exhaust question
 

I’m not to familiar with dry exhaust systems. I know they have benefits over a wet setup. I’m looking at 2 boats and they both dry exhaust. I run on a lake that has noise restrictions. Would I be able to install turn down’s to help quiet it down a little bit?

Ayuh,.... Down-turns only quiet it when at idle, 'n just above idle,.....

Once ya break over onto plane, it tends to be open pipe Loud,....

Dry exhaust is insanely loud. Not even sure a down turn at idle Would help

What’s the best way and cost to convert it to wet?

You are going to have to provide some variables before we can solve that equation.....
1. why do they have dry exhaust in the first place?
2.What kind of exhaust and risers do you have??

If the engines are built for dry exhaust, or the exhaust was converted to dry because of reversion, then you are taking about a new cam, possibly lifters, pushrods, springs... then that will change the power, so now you are looking at prop work or new props.

If its just dry exhaust because the previous owner wanted it to sound cool, then your only going to be into it for a set of tips and buying your buddy with the tig welder a case or two of beer and a mid level hooker.

My neighbors love dry exhaust 😊

I have Dry Exhaust.

i have an aluminum swim platform and clamp on mufflers - the clamp on mufflers are the air activated kind, but they are inoperable. And stuck in the open position. I tell you this because mine are, for some reason, more tolerable than any other dry pipe boat I've ever heard. I also have big tube headers which I think makes it less raspy (as ridiculous as that sounds).

It's not terrible as the driver or front passenger, but it's a lot for people sitting in the rear seat to handle. If we are running more than a couple miles I like to wear some ear protection..... Idling isn't that much different in my mind. When you are backed into a slip and fire them off everyone in the marina will know you are leaving.

Two true stories:

1. I started mine in the front yard today and a friend that lives a couple miles across the river the way the crow flies texts me and asks if I just started my boat.

My neighbor 12 houses down was on a conference call last summer inside his house and someone on the line was a Motorhead and when I started it up he interrupted the call and asked my neighbor what the hell the noise was.


I would never buy a dry pipe boat just to be cool, that's for sure, nor would i convert one to be "cool". The cool factor of dry pipes is VERY limited, especially when it's your boat.....

I can’t answer why they have dry exhaust. My guess would be it’s for a performance aspect. I haven’t got into specifics with the sellers on what riser, headers are installed. Just looking to get some background info. By the sounds of things it’s not going to be a simple fix or an inexpensive change over.

Mine are swaged at the tip so kinda mixes as the exhaust leaves the tip. Engines haven’t been started yet so I don’t know what to expect. Would this set up be any quieter than if the water didn’t mix at all?

I think that will temper it some. Again, I think mine are tempered just having the inoperable clamp ons still bolted on.....

Mine are dry to the tip, mix in at the last inch or so. Its not to bad in the cockpit, though I really didnt realize how loud it was until my brother in law videoed a fly by I did

I had dry to the tip on 4.5" tails and measured 102dba at idle. Blown 509's. Never sounded too loud to me. If I wanted to be quite Id hit the switch on the CMI's tips and never a problem.

My exhaust was dry to the very tip. I installed these last summer and it made a huge difference!

https://www.hardin-marine.com/p-1262...-mufflers.aspx

I'm sorry to add a possible stupid question here. Some of the above replies say the tail pipes are dry until the very end. How is that possible? isn't it wet until the very end, than exiting the water overboard at a different location away from the tail pipes?

They are still water jacketed for cooling purposes, it's just where the water is mixed - after header, into the tail. After the tail into the tip, through the transom. The water in mine still run all the way through the header, through a jumper hose into the tail then out the end of the tail where it diverts into a through hull dump.

I think the CMI website has some good explanations on it.....

you simply inject water into the exhaust it the very end, I have stainless marine. I cut the risers before the water enters the exhaust the exhaust stream and extended the inner and outer tubes then welded the part that injects the water at the end. That took care of reversion issues.

Did you see any loss in power or speed at all. I purchased some 4 1/2” hpi’ clamp ons and would like to do a back to back comparison. If it tames it down a bit with little to no loss in power I’ll be pleased or at least many of the lake owners will.

I don't mean to change the direction of this thread.....I don't know! seafordguy is exactly what I was saying. Unless I'm crazy the water never enters the exhaust. It's on the outside of the exhaust for cooling and inside the double wall. The possible reversion issue comes, I believe, at an idle. The water is exiting the double wall portion of the tail pipe and is being sucked back into the exhaust pipe portion and sadly back into the engine/cylinder. By closing off the double wall and welding a bung to have the water exit separately away from the exhaust it does not get sucked back in. Unfortunately since all these pos headers end up leaking somewhere you still hurt your engine. But, that is an all together different subject

Yes - mine never enters the exhaust at all. I do believe mine have a couple weep holes so the water doesn't get dead headed at the end of the pipe and overheat.....

I run dry to the very tip than out.

The difference over traditional wet is its at the very end and has to come way back to do any damage.

For most that is enough, BTW my chitty e-top headers did finally start leaking,,,,,,, 21 years after new.
Half of that in salt water.

21 years. You are a lucky man

Damn dude you were hauling arse... Boat sounded killer!!!

Don’t confuse dry or wet with double walled water cooled.

Dry exhausts in i/o boats are still water cooled, but don’t have water enter the exhaust stream.

Wet exhausts have water enter the exhaust stream. In i/o boats they are also double walked water cooled.

I have Stainless Marine dry exhaust ,my water dumps out on the bottom of my pipes from a hole the size of a nic
https://cimg6.ibsrv.net/gimg/www.off...6831b48db.jpeg
kel

Question for LS 376/525 with cam duration 226 deg intake, 236 deg exhaust, 110 LSA, "Kodiak marine" alu risers we have available two solutions:

a.) extended pipe for dry exhaust by 26 inches, 5 inches mixing space and then gatlin mufflers. Exhaust is at an angle of 15 degrees down.
b.) Dry exhaust to the end.

Please for opinions.

I run GGB insertsi n my 4.5" dry pipes and it does make them tolerable.

Certainly didn't notice any loss but did quiet them down.

I have some clamp on Gibson and I used them once on LOTO- Did quiet them down a lot.
Lost both drives that weekend and haven't used them again :lolhit:

I am of the opinion that if you can hear the exhaust noise in the boat you aren't going fast enough. Once I hit 70 all I hear is a hum and deafening wind noise. I have a single with Lightning wet headers and people can still hear me after I've disappeared over the horizon.

GGB have proven effective in wet or dry and I love my set, but I don’t think they’re available anymore.

I had double wall full-length headers with a 4-1/2" collector plus a 12" extension (collector about 18" long of 4-1/2 stainless) completely dry. I was asked not so nicely to leave the lake we were testing on, as the lake patrol had "numerous complaints of windows shaking". Tried 4-1/2 inch switchable mufflers which did help tremendously, but even open they necked down to about 3-1/2 inches and seemed to take 1-2 MPH off the boat.

I went in where the overflow bung was (right behind the flange) and drilled a 1/2 hole right there in the inner exhaust tube, and sprayed water in there. That made it bearable for wife and neighbors, but you could still hear it for MILES away. More throaty, less pop!

(Sorry about the dirt, boat was in storage for 9 years and in restoration now)
https://cimg8.ibsrv.net/gimg/www.off...8fc0203cb2.jpg

Well, I sent them an Email inquiring about the marine line and they said they are presently working on it. Hopefully they get stuff out soon.