Thru Hull Exhaust

[samm835]

Re: Thru Hull Exhaust

I wasn't sure if someone said anything about this being loud or not?????? So will it be loud? HA, After I got my question about cost, my next question was going to be.....is it extremly more expensive to have it both ways? The thru hull and the thru prop. This way when I want a little loud cool sound I can have it, and then when I go through a cove and want to chill I can have it to....you know I want my cake and eat it to, why not have it both ways my boat right? HA......oh well I guess there is that small factor of cost. What my wife doesn't know won't hurt her, although it could hurt me when/if she finds out!! Thanks for the help guys!
BTW I don't care about more horsepower, I just like the sound if I wanted more hspwr I would have bought a bigger motor. Not do a small thing like add exhaust.

 

[bjcsc]

Re: Thru Hull Exhaust

Well I'm on the opposite side of the coin. My exhaust is Corsa thru hull and I wish it was thru prop...of course I don't have a prop so I don't have the option. One thing to consider is that the thru hull exhaust will be loud. While I do like the muscle car sound, it's nice when I'm on other people's boats and we can have a conversation while on plane...

 

[Coors]

Re: Thru Hull Exhaust

On my 5.7 thru hull, just a throaty roar. Not loud, as the water exhausting muffles it down.
When my stepson bought it, with a rigged auto engine in it, my wife hated it (I never rode in it). After the correct marine engine in it, my wife says don't install mufflers, and now I agree.
The exhaust water really muffles the noise, at least in an old OMC that shoots spray out the exhaust (at power) 30 feet
At idle and make way, just a quiet rumble.
It ain't like open headers, or a loud outboard, in fact, quieter than an outboard.

 

[magster65]

Re: Thru Hull Exhaust

Most of my buddy's boats have through-hull exhausts... all of which are switchable at the dash. I had a 23' Baja that had a manual locking switches but it was switchable. Trust me on this one... make it so you can silence it! It's not noisy inside the boat but anything behind you gets it. Coming back to port late at night (open)... it's just wrong... it'll be annoying to you too.
The installation isn't that difficult... follow the instructions provided. The toughest thing for me would be drilling the holes in my boat... drills and boats... they don't go together
Having said all that... I love the sound!
You shoulda' heard my Baja (7.4 bravo 1 w/2 x 4.5" exhaust) at 5200 rpm... yummy!!

 

[Zetman]

Re: Thru Hull Exhaust

What are you guys switching on and off on the exaust?

 

[ziggy]

Re: Thru Hull Exhaust

What are you guys switching on and off on the exaust?

i only got a L6, so i just ain't gonna be hip...anyways, there's a diverter in the exhust pipe. swicth it one way it exhusts thru the prop(quite), switch it the other and it's open to the thru hulls(real loud).....

 

[QC]

Re: Thru Hull Exhaust

I have thru hull with my 6.2 and there are times when it is embarrassing. I was sure Mrs. QC was gonna make me change it, but she actually likes it, go figure . . . I guess JB would've known that (smart aleck reference to a DC thread ).

Where we boat about half are fixed thru hull, some Monster power and waaaaaaay louder than mine. I beat the noise test at the ramp by something like 2 dB There are a lot of add on muffler exhaust tips being sold these days . . .

Inquiring minds have to know . . . How in the flyin' flip does thru hull get you better oil pressure? Or even make it run cooler for that matter?

 

[MikDee]

Re: Thru Hull Exhaust

The boat pictured above is horrendously loud on start up because there is no water in the manifolds. However, even after everything gets going it's still loud.

We run the exhaust through the prop 95% of the time.

That boat came with that set up. Would I have opted for it? NO.

Well, It is a big block 454 motor, not a 350, or 305.

 

[MikDee]

Re: Thru Hull Exhaust

Inquiring minds have to know . . . How in the flyin' flip does thru hull get you better oil pressure? Or even make it run cooler for that matter?

Do you think I lie!? or make stuff up!? I call it like I see it!
Go figure, you have a mechanical mind,,, twin wet manifolds, and an engine full of water going out what a 2" hole at the Y-pipe, then thru a prop, with a large hub in the middle, and only a coupla slots open! as opposed to, going thru 2- 3" open tips! The engine runs cooler, hence oil pressure comes up, Go try it yourself if you don't believe me, it worked for me, on 4 seperate boats!

 

[ziggy]

Re: Thru Hull Exhaust

cabin fever's settin in.......

 

[Zetman]

Re: Thru Hull Exhaust

Thankyou

 

[Coors]

Re: Thru Hull Exhaust

cabin fever's settin in.......

lol, seems to be

 

[SuperNova]

Re: Thru Hull Exhaust

I have an '86 Wellcraft Nova with twin 260 hp 350's with thru the prop exhaust and my B.I.L. has an '83 Nova with twin 260 hp 350's with thru-hulls and I can tell you for sure---I am a load happier with my quiet boat than he is with the noise. Yeah, when you're idling thru an anchorage in the middle of the day or motoring out of the marina it sounds cool as h**l and everybody looks around when you fire those engines up, when you're running down the Bay for a couple of hours.....well after about 15 minutes the noise gets old...after two hours you have a pounding headache...no fun there. Plus on my boat I can still listen to the radio or have a normal conversation even at full throttle. And when I go motoring in to an anchorage at midnight, I am not in so much of a hurry to get the anchor set and get her shut off before I irritate someone....I can take my time and get her set right.
--
Stan

 

[QC]

Re: Thru Hull Exhaust

Sorry to stir the cabin Mik, but I just don't see it. As an example the 5.0, 5.7 and 6.2 Merc all have the same cooling system and they use the same manifolds and risers. They all have a 160 degree thermostat, and use the same raw pump and engine pump if its a Bravo. So if slightly more restricted exhaust (more flow through the same stuff will result in higher pressure) caused a measurable rise in temp, the 6.2s oughta run hot and their oil pressure should be lower. and I simply do not think that's the case . . . Whether it is flow or pressure the 6.2 has to push more out, and the 5.0 less, so it just doesn't figure to me. I understand why it might, I just don't think it does . . . too much good cold water to work with

BTW, I can't believe that somebody hasn't published a good test of the switchable systems, with back pressure and speed changes etc. It is soooo easy, you can do it literally by flipping a switch. I searched for an hour. Has anybody else ever seen a test?

 

[SuperNova]

Re: Thru Hull Exhaust

BTW, I can't believe that somebody hasn't published a good test of the switchable systems, with back pressure and speed changes etc. It is soooo easy, you can do it literally by flipping a switch. I searched for an hour. Has anybody else ever seen a test?

Are you kidding me?!?! I think the makers of the switchable systems buried any tests that were done, cause the tests would prove that people who bought the systems were throwing their money away....and we wouldn't want that info to get out to the general public...now would we?

 

[MikDee]

Re: Thru Hull Exhaust

Sorry to stir the cabin Mik, but I just don't see it. As an example the 5.0, 5.7 and 6.2 Merc all have the same cooling system and they use the same manifolds and risers. They all have a 160 degree thermostat, and use the same raw pump and engine pump if its a Bravo. So if slightly more restricted exhaust (more flow through the same stuff will result in higher pressure) caused a measurable rise in temp, the 6.2s oughta run hot and their oil pressure should be lower. and I simply do not think that's the case . . . Whether it is flow or pressure the 6.2 has to push more out, and the 5.0 less, so it just doesn't figure to me. I understand why it might, I just don't think it does . . . too much good cold water to work with

BTW, I can't believe that somebody hasn't published a good test of the switchable systems, with back pressure and speed changes etc. It is soooo easy, you can do it literally by flipping a switch. I searched for an hour. Has anybody else ever seen a test?

QC, I'm sorry if I came on a bit strong, I can only tell you my experience, you mocked it, so I had to explain myself, if you believe me, or not that's up to you, that's how it worked out for me. Also, the thermostat I always used, and was the standard for raw water cooling, was a 145*.
, and my engines always ran cooler, very close to that figure at all times after the conversion to thru-hull exhaust. Take it or leave it, thats all I have to say on this subject.

 

[magster65]

Re: Thru Hull Exhaust

I've been in lots of boats with switchable exhaust... there's no speed advantage with thru-hulls over thru-hub... it's all for the sound. We've done extensive 'testing' on the topic
Kick this one around...
The thru-hull is open exhaust... and therefor less back pressure of course. At speed though the drive pushes a hole in the water creating a vacuum to 'suck' the exhaust out thru-hub.

 

[QC]

Re: Thru Hull Exhaust

The thru-hull is open exhaust... and therefor less back pressure of course. At speed though the drive pushes a hole in the water creating a vacuum to 'suck' the exhaust out thru-hub.

I am buying that, Magster to the rescue.

 

[arks]

Re: Thru Hull Exhaust

BTW, I can't believe that somebody hasn't published a good test of the switchable systems, with back pressure and speed changes etc. It is soooo easy, you can do it literally by flipping a switch. I searched for an hour. Has anybody else ever seen a test?

I remember back in the 80's, one of the magazines (maybe "Powerboat") did a test using a pair of identical Bajas- 21 footers I think, with smallblock Mercs. One had thru prop and the other had thru hull exhaust. The results were so close that they were essentially the same....bottom line was "no significant performance increase with thru hull and a smallblock".

 

[Mkos1980]

Re: Thru Hull Exhaust

Trailerboats did an article in last months mag on I think on the 27 Baja. 350 Magnum and they got 48MPH closed and 49MPH open