PDA

View Full Version : Through transom exhaust



Speedin' Ian
02-07-2004, 04:26 PM
I am interested in putting through transom exhaust on my boat, it has a merc 260 with an Alpha 1 outdrive. I know I will have to remove the motor to get ride of the y-pipe, but what else is involved. I am worried about cutting the holes in the boat:eek: . Has anyone else done this, can you lend me any advice.

Jordy
02-07-2004, 04:36 PM
Not to lend a negative view, but I'm just wondering what you're trying to accomplish. Are you looking for more performance, better sound, something to do? Are you planning on changing out the stock risers and manifolds or are you going to leave them stock and just go out the transom? The reason I'm asking is just to see if you have considered the amount of work that is involved and taken into consideration the gains you'll see after it's done.

Havasu Hangin'
02-07-2004, 06:09 PM
I did mine. Before you pull the engine, mockup where the exhaust will exit the transom (I used L-pipes and hose from Eddie- sorry Rex), and ran mine under the swimsteps- this is kinda important to make sure there is nothing blocking the route (pump, blower, etc.).
After I pulled the engine, I unbolted the Y-pipe, and made a block-off plate. Then I drilled a pilot hole from where I mocked up where the tips will go (the center of the tip cutout). Measure a 4" circle around the pilot hole (on both sides) to make sure they are in the right location (and even). Then, measure another inch, as that how much room the flange will need.
At this point, if the pilot hole is off, you can re-drill it, as it will be part of the material removed anyway (unless you are 2" or more off!)
Put masking tape on the transom to keep the gel safe. Use a 4" holesaw and take your time. After your done, grind out a little (1/8" or so), and put some resin on the exposed wood.
After the resin dries, insert the tips (I got mine from Eddie Marine-sorry Rex). Mark the holes...remove the tips and drill the holes. Remove the masking tape.
Silicone the flange, and re-insert it. Screw the tips in.
After you install the engine, put the hoses and clamps on loosely (I use double clamps from Eddie Marine- sorry Rex). Just make sure there is no binding and tighten the clamps up.
All in all, it looks tough...but is one of the easier jobs. Measure twice...or three times (if you make a mistake with the hole saw...it'll cost you $800 bucks or so to replace the wood), and use the hole saw once.
PS- don't listen to Jordy...he's a "half-empty" kinda guy (who is still reaping the full performance benefits of a velocity stack).

Kim Hanson
02-07-2004, 06:20 PM
Why would you do this though? To make the exhaust quite, get rid of the headers hanging out the back?
Jordy fish bowls works HH, I seen pictures:D .........( . )( . )......:cool:

Speedin' Ian
02-07-2004, 06:30 PM
I'm doing it strictly for the sound and do not expect any performance gaains. I plan on using the stock manifolds and picking up some elbows and tips from Rex Marine.

Mandelon
02-07-2004, 06:32 PM
And when you're done you'll have a boat that probably won't pass the new exhaust law like the rest of us. :(
I read somewhere you could pick up 3 to 5 mph with through hull exhaust....:rolleyes: :D

Havasu Hangin'
02-07-2004, 06:36 PM
Originally posted by Kim Hanson
Why would you do this though? To make the exhaust quite, get rid of the headers hanging out the back?
Kim- the Merc setups run the exhaust through the hub of the prop. By getting away from that...you let the engine breathe a little more (like you outbored guys do).
It also keeps the hot exhaust from going out the outdrive.
Originally posted by Kim Hanson
Jordy fish bowls works HH, I seen pictures..
Well...I guess we can't argue with that 5 MPH he pick up when he put the velocity stack on!
Originally posted by Mandelon
And when you're done you'll have a boat that probably won't pass the new exhaust law like the rest of us.
Actually...off plane...my boat just makes bubbles.

Kim Hanson
02-07-2004, 06:41 PM
Originally posted by Mandelon
And when you're done you'll have a boat that probably won't pass the new exhaust law like the rest of us. :(
I read somewhere you could pick up 3 to 5 mph with through hull exhaust....:rolleyes: :D
I run SuperTrapps on my V-Drive, it's still loud! I think I will be able to use it though..........( . )( . )........
I read somewhere you could pick up 3 to 5 mph with through hull exhaust...In your dreams..BBbWWWWwHHhaaaaaaaaaa:rolleyes:

LASERRAY
02-07-2004, 06:50 PM
Originally posted by Mandelon
I read somewhere you could pick up 3 to 5 mph with through hull exhaust....:rolleyes: :D Our "brother in smack" Kilrtoy will never live that down!:D J/K Kil.

Havasu Hangin'
02-07-2004, 06:51 PM
Originally posted by Kim Hanson
I run SuperTrapps on my V-Drive, it's still loud! I think I will be able to use it though...
My stereo is actually louder than my exhaust...what a screwed up boat.

Kachina26
02-07-2004, 06:54 PM
Originally posted by Mandelon
I read somewhere you could pick up 3 to 5 mph with through hull exhaust....:rolleyes: :D And I was taking the high road............I knew someone would go there.:D Maybe this setup would spice up that 50MPH Commander?

Kim Hanson
02-07-2004, 06:55 PM
Originally posted by Havasu Hangin'
My stereo is actually louder than my exhaust...what a screwed up boat.
No, That's " TIT'S "..............( . )( . ).............:cool:

Dr. Eagle
02-07-2004, 06:57 PM
I did the exhaust on my old Eliminator Knock off 21 footer that I had about 8 years ago. It had an OMC King Cobra w/350. I put on the Imco manifolds...(damn disappointing) and I think they were Gaffrig tips with mufflers.
I didn't take the Y pipe off and used some rubber caps with hose clamps for 3" pipe. I put the tips under the swim steps too and had to use elbows to make a double 90. Boat still runs and sounds great...my neighbor bought it from me.
On my Ultra they went through the transom with Gil tips that have some sort of very unique muffler, cuz it is very quiet. Too quiet for my tastes, but given the current noise on the water laws...perhaps for the best!

77charger
02-07-2004, 07:56 PM
When my y pipe went out on my eliminator i almost went thru transom for just a little more(i had a shop replace the pipe since i didnt have time).Iwas told that the benefit wouldnt be anything but louder exhaust also told by others.so i left it stock and quiet now with al the noise regs coming out i am glad i did.Aint nothing like passing a jet boat also that has stock power making all noise with otts too by a boat sounding like a vacum cleaner with stereo blastin:D :D :D
I get enough noise with the boat in my sig anyways now that is real horsepower

Kilrtoy
02-07-2004, 10:31 PM
I read somewhere you could pick up 3 to 5 mph with through hull exhaust
That only applies to mo fo's like myself.
Sometimes the truth is HARD TO SWALLOW,
I'll work it down slowly for you thoughhttp://www.riverratlife.com/forums/board/ubb/graemlins/sex2.gif

fourspeednup
02-07-2004, 10:33 PM
Originally posted by Kilrtoy
I read somewhere you could pick up 3 to 5 mph with through hull exhaust
That only applies to mo fo's like myself.
Sometimes the truth is HARD TO SWALLOW,
I'll work it down slowly for you though
Nice come back:D

Jordy
02-08-2004, 11:54 AM
Originally posted by Havasu Hangin'
PS- don't listen to Jordy...he's a "half-empty" kinda guy (who is still reaping the full performance benefits of a velocity stack).
If you'll notice, I didn't say anything either way in regards to the benefits. I merely asked what he was looking to accomplish and did it without putting attitude in it. Just trying to help the guy out... ;) :D

Jordy
02-08-2004, 11:55 AM
Originally posted by Speedin' Ian
I'm doing it strictly for the sound and do not expect any performance gaains. I plan on using the stock manifolds and picking up some elbows and tips from Rex Marine.
Cool. Just wanted to make sure you knew what you were getting into. It should sound sweet. Good luck with the project. :D

mirvin
02-08-2004, 01:31 PM
Without sounding dumb:rolleyes: , is it really necessary to pull the engine to do the through transom exhaust? I'm considering it and in my engine compartment there seems to be plenty of room to accomplish this without yanking the motor:confused:
What am I missing?
350/ Volvo Penta 290.
Mirvin:cool:

Havasu Hangin'
02-08-2004, 01:38 PM
Originally posted by mirvin
Without sounding dumb...is it really necessary to pull the engine to do the through transom exhaust? I'm considering it and in my engine compartment there seems to be plenty of room to accomplish this without yanking the motor...
What am I missing?
Taking the Y-pipe out and bolting up the blockoff plate is much easier with the engine out. If you wanna get the Y-Pipe out, you gotta pull the engine (unless you cut it up into pieces with a sawsall?).
Or you could just cap the Y-pipe (like Nurse Beagle).
There's always "plenty of room in the engine compartment" until you have to hang upside down in there for a couple hours...

Dr. Eagle
02-08-2004, 06:58 PM
Originally posted by Havasu Hangin'
Or you could just cap the Y-pipe (like Nurse Beagle).
Thanks for the love HH... right back at ya...:D

Havasu Hangin'
02-08-2004, 07:11 PM
Originally posted by Dr. Eagle
Thanks for the love HH... right back at ya...:D
Stop it...I think I'm gettin' a little misty over here...http://www.planetsmilies.com/smilies/sad/1/sad55.gif

Kilrtoy
02-08-2004, 07:36 PM
Stop it...I think I'm gettin' a little misty over here...
That is the alcohol leaving your pours, from RADIATION

Dr. Eagle
02-08-2004, 09:14 PM
Originally posted by Havasu Hangin'
Stop it...I think I'm gettin' a little misty over here...http://www.planetsmilies.com/smilies/sad/1/sad55.gif
LOL, rrriiiight...:D