changing to thru hull exhaust

[Bondo]

Re: changing to thru hull exhaust

Ayuh,......... And it All in Your head...........

No, it's all in your head, that there's nothing to be gained. You can't make a statement like this, unless you've done it! and I have, more then once.

Ayuh,........ I never said I Haven't done It,.... I Have,... Quite a few times....
And,......
I Stand by My Statement.......
As stated by Riverjet,..... The Major Choke point on a SBC is the Exhaust Valves,+ the OEM Manifolds,....... Period.......
Without spending the Big Bucks for True exhaust Headers,......
Thru-Hull Exhaust is a Waste of Time,+ Money......
All it does is Pi$$ Off Everybody else who's boating or living on the body of water that You're boating on.......

Btw,.........

I'd recommend capping it off somehow, maybe a couple of 3" PVC one way vertical check valves. (water goes out, nothing comes in)
some people say capping it off causes a suction at the prop, which will slow you down.

That's a Crock of the Smelly Stuff too.................

The Proper way to accomplish the task is to Remove the Y-pipe,+ install a Block-off Plate to the inner transom plate.......

Here's a set of 4, 1/2" Thru-hulls,....... Free Breathing,+ LOUD......
It took about 4 or 6 Tries to get them Quite enough to satisfy the authorities,...... Muchless Myself.......

They started out just Straight out at the transom,...... I added the Downpipes to get the outlets below waterlevel to Quite it at Idle.......
When I do it Again,+ I Will,....
The Downpipes will be Inside the boat.......
But,........
I'm Not kidding myself,....... There's Absolutely No HP Gains to be found with this.......

 

[riverjet502]

Re: changing to thru hull exhaust

If making some noise is the goal I would suggest this method...


Camera cut it off but there are 4 yes 4 460 fords in this engine bay... Looks fun to work on doesn't it???




Shot with DSC-P100 at 2007-08-18

 

[riverjet502]

Re: changing to thru hull exhaust

These are the Gil manifolds that I run with Stainless mandrel bend 4.0 inch risers. See how they come down in the rear? With the "S" pipe attaching at this point to shoot straight through the hull. This lowers the tips to well under the swim pad which makes it quiter at no wake speeds. In the left exhaust tip you can see part of the baffle insert. These are Gils as well. Without baffles 112 db on the A scale. With Baffles 96db.. Nice throaty sound but still 10 over the law.



Shot at 2007-08-18





Shot with DSC-P10

 

[MikDee]

Re: changing to thru hull exhaust

Aha, Bond-o, You have done this before,

All it does is Pi$$ Off Everybody else who's boating or living on the body of water that You're boating on.......

True if you abuse it, it's like anything else, just take careless jet skiers, or boaters, watercraft operation for example. I like the sound, but I really don't want to be offensive, It all boils down to respect, and consideration of other people, and using common sense. My 305 wasn't that loud with the rubber exhaust tubing, but my 350 I had to put mufflers on it.

some people say capping it off causes a suction at the prop, which will slow you down. my quote originally

This is as easy to believe as your telling me that there is no power gain, then there should be no power loss, right?

The Proper way to accomplish the task is to Remove the Y-pipe,+ install a Block-off Plate to the inner transom plate.......

I think you would have to remove your engine in order to do this, no?

 

[Sorrento 25]

Re: changing to thru hull exhaust

No appreciable gains even on a big block with an alpha? If I ran a single exhaust with a diameter equal to that passage in my alpha drive on any big block vehicle with exhaust manifolds it would cost me HP. Does the "suction effect" from the prop really make that much of a difference?

 

[eriediver]

Re: changing to thru hull exhaust

If making some noise is the goal I would suggest this method...


Camera cut it off but there are 4 yes 4 460 fords in this engine bay... Looks fun to work on doesn't it???




Shot with DSC-P100 at 2007-08-18

I wanna see the rest of the boat

 

[riverjet502]

Re: changing to thru hull exhaust

The above pic was sent to from my brother. They were in the Wiscosin Dells earlier in Aug. The quad big blocks power one of the river jet boats you can go for a ride on...

 

[dubge]

Re: changing to thru hull exhaust

Quad 460s might be a little out of my budget right now

Thanks guys for all the input and pics it helps alot!