Thru hull exhaust

[WETSUT]

I have an 18 foot ’96 Scarab Sprint with 4.3 Mercruiser V6. I am very interested in installing a thru hull exhaust on this boat soon and would like to know where I can get instructions on doing so. I read the forum on the guy wanting to do this installation on his 3.0 motor and there was no useful info given, just the fact that he would gain no additional power. This boat sounds great when running out of the water but too quiet while in the water. <br /> I need to know if I would have to change my original exhaust manifolds? Do I need to install anything special in the transom to protect from heat or to seal around the exhausts? Any particular size of pipe be better?<br /> One last question, I have a hole saw…anyone wanna come over and help? ;>)

 

[Bondo]

Re: Thru hull exhaust

I just clicked on the Big Red Search Button at the top of every page,+ came up with 7 hits for "4.3 thru hull"..........<br />Most All of the answers you're looking for are there........ <br />

This boat sounds great when running out of the water but too quiet while in the water.

If you like the sound of a Piper Cub flying away,.. You'll be Pleased.....<br />It Don't sound Cool like a V8... I Know.....<br />

I need to know if I would have to change my original exhaust manifolds?

No,..... But,. That's Where the Power Gains come from....<br />

Do I need to install anything special in the transom to protect from heat or to seal around the exhausts?

Ayuh,....... That's where the Exhaust Tips come in.......Bedded,+ Sealed,... With Flappers maybe.....<br />

Any particular size of pipe be better?

4" is about the Most Common, now adays.....<br />That Should be the Inside Dia. of the Rubber Exhaust Couplers at the end of the Elbows/Risers that are on your boat Now...........<br />

One last question, I have a hole saw…anyone wanna come over and help?

Naw,...... Too far South for Me..... I don't know How you people stand the Heat...................

 

[Mahoney]

Re: Thru hull exhaust

Just curious, I find it kind of ammusing there are so many people willing to go through the time and expense of putting thru-hull exhaust systems on V6's. I can't help but think these are the same people spending thousands on the little honda accords with the glass packs installed. I am only 30, and am not making judgments, I remember the stuff we used to do when we were younger to our cars, but can't imagine all these posts are coming from anyone over the age of 28.<br /><br />As anyone here will probably recommend and from what you can read on the posts, find a boat with a V8 for thru-hull. Although I do not fault you for one minute for wanting to tinker with your boat, I would just concentrate time and energy somewhere else rather than wanting to make it sound like a loud lawnmower.

 

[Scaaty]

Re: Thru hull exhaust

My take. People are sick of noise. They are up in arms over MUFFLED Jetskis. And noise travels for MILES on open water. All you will do is make more laws against it, and the people that make laws live on the shoreline with your stolen tax dollars. <br />Ps. Yep, this is from a Harley rider

 

[WETSUT]

Re: Thru hull exhaust

Well well well, this topic certainly does draw a bit of attention doesn't it. I took your advice and located quite a few other posts on thru hull exhausts and seems like the majority of the replies are against the idea all together. <br />My question on shielding around the exhaust on the transom...my concern was sealing the hole after cutting and protection from the heated tips on the surrounding fiberglass to keep from burning. <br />I will most likely be trading motors at some point, just not anytime real soon unless this one argues the point with me and quits one day. I hear a 350 will go in nicely, my main concern with that on the smaller boat is the weight, and keeping the front end down...I like to wheely my bike, but it doesn't float <>

 

[Don S]

Re: Thru hull exhaust

My question on shielding around the exhaust on the transom...my concern was sealing the hole after cutting and protection from the heated tips on the surrounding fiberglass to keep from burning. <br />

There really should be that kind of heat at the tip. The exhaust goes through rubber hoses and water is introduced into the exhaust as part of the cooling system.<br />Here is some info on thru-transom exhaust. web page <br />If you are talking about an all dry exhaust system, that's a whole different ball game, and shouldn't be done at all inside an engine compartment.

 

[baja power]

Re: Thru hull exhaust

THIS POST EDITED BY BAJA POWER

 

[flashback]

Re: Thru hull exhaust

Hey Bondo, just curious, do you like the sound of a piper cub?? Ive read a lot of your posts on straight pipes for a 4.3 and was just wondering why you did it to your boat. I would guess you probably put some custom headers on it so you went to straight exhaust for performance...

 

[Jilly - 5]

Re: Thru hull exhaust

The only reason for thru-hulls is to help relieve back pressure on big cid engines (400+). And that still only just helps, so long as exhaust gases still have to fight their way through course cast iron manifolds on their way to the "pipes". If you want noise w/o performance, do the job. If you want performance and are willing to live with noise (check some offshore rigs leaving a small harbor !), get rid of manifolds and risers and go straight-through right out of the engine compartment with custom headers, like a dragster. But even that might give you only 10% hp increase. For more hp, go to serpentine belting (5%), or larger v-belt alternator pulley (3%). All w/o noise. Then, of course, you can go inside (cam, valves, MSD fire, etc.).

 

[Ralph 123]

Re: Thru hull exhaust

You know what I like most about my thru hull? I just look over the transom to see what kind of water is flowing through the system.<br /><br />Last time out last season I saw one of the temp guage start to rise, looked over the back, no water.. I/O water pump died. Shut it right down before it could overheat

 

[Bondo]

Re: Thru hull exhaust

Originally posted by flashback:<br /> Hey Bondo, just curious, do you like the sound of a piper cub?? Ive read a lot of your posts on straight pipes for a 4.3 and was just wondering why you did it to your boat. I would guess you probably put some custom headers on it so you went to straight exhaust for performance...

Ayuh,.. Well,.. I guess I'm just an Old MotorHead at Heart............. <br /><br />When I did the 140hp/4.3LX swap, I knew that the V6 would sound Better than the 140hp with a ripped exhaust bellows............... <br />And,.. I had a bunch of 4 1/2" SSteel pipe laying around,.... So, Right off the Risers/Elbows with it,+ Straight Out the Back......... Built it All myself,.. Baffles,.. Flappers,..Transom Flanges/ Angle-cut Tailpipes,..<br />It Looked Really Cool....... <br />But,.......<br />It got Old Real Quick....... 12/18hrs Trolling,....Uh Boy,...<br />After that I welded the angled cut-off pc.s back on,.. Pointed Down...... 90*..... Looked Stupid Then.......<br />But, It Quited Down to Dead Silence at Idle......Well,.. Except when a wave tipped the stern Up,.. Kind of a neat little Rumble then....<br />After that Discovery,.... I Ripped everything back out,+ Started Again.......<br />Now,.. They come off the Elbows like they did,+ they drop down,+ away at a 45* angle at the outside of the transom ending at a point just above,+ to the inside of my Trimtabs..........<br /><br />Now, I've got a design that'll pass Any Noise Test,....And, If I Had the PowerPlant, It Could Breathe..................

 

[flashback]

Re: Thru hull exhaust

Ralph, I can relate to that,,,,,, I have a little outboard on my sailboat and I check the **** pipe every time I crank it........

 

[16Pilot]

Re: Thru hull exhaust

Mahoney, I am only 25, I do post some of those questions. But guess what... I could build a 4.3 for what you would pay for a 350 that would spank it. But I agree with some of the post. I personally think the 4.3's sound great with through the hull.

 

[flashback]

Re: Thru hull exhaust

I always thought it would be cool to come out the sides of the boat kinda like an old buick . I wonder if anyone has ever done that? I have a swim platform on my boat and am afraid of folks using the pipes as hand holds or something. thats why I have never done it...

 

[weatherz]

Re: Thru hull exhaust

Flashback... 24' FourWinns Liberator 460 that my buddy has has factory side exit exhaust, pretty cool. It has big 5 gallon bucket mufflers in the boat so it is quiet. Think it is about early 90's.

 

[s1jor]

Re: Thru hull exhaust

have seen some of the campion boats with side exiting exhausts

 

[Northern Eclipse]

Re: Thru hull exhaust

Yep Corsa makes side exhaust, Crownline also used them... eBay is a good source to locate a pair,since there about $700 bucks new a pair.

 

[Mahoney]

Re: Thru hull exhaust

I am all for tinkering with your boat, but from all I have read, through hull exhaust are a pricy proposition. $700-$1000 can but you some pretty cool accesories and preventative maintainance items. But I would be the first to admit I am not easily talked out of things when I want to do it.<br /><br />I say do it if it makes you feel good and you got the cash, which I don't! I could be just bitter, ha. <br /><br />I am not sure on local ordinances and where you boat, but I would hazard a guess there are some populated lakes that might ban open exhaust systems, and might be worth checking into first.

 

[Bill kubiak]

Re: Thru hull exhaust

My single thru hull on my 351 is a big bronze affair with a one inch water hose also connected to it right before it goes thru the hull. That hose comes from a pickup on the bottom of the boat, is that hose for additional muffling. 1980 Penn Yan Explorer.
at the bottom of that thru hull just at the waterline it has what looks like an inverted bronze funnel in the middle of the hole, what is that for?

 

[SeanMcl]

Re: Thru hull exhaust

just the fact that he would gain no additional power. This boat sounds great when running out of the water but too quiet while in the water.

Just put the sound of a noisy V8 on your ipod, put your earplugs in and crank it up. Cheap, you get the same result and you don't inflict your love of noise on the rest of us.