Exhaust Question Comp TS6M

[Ontarion]

I bought this boat late last summer. It is a 1996 Comp TS6M with a PCM fuel injected GT40 and around 275 hours.


http://i536.photobucket.com/albums/ff321/Ontarion46m/100_0238B.jpg


The boat easily burry’s the 50mph Speedo’s with the stock 13x13 3 blade prop at around 5200rpms.
I am going to try a 13 x 14 this weekend to see if I can bring the revs down to 4800 without too much sacrifice.

The boat is used as a cottage boat: Skiing, Boarding, Tubing, Ripping around the lakes disturbing the neighbors, mid-lake swim platform, and ferry to the marina for ice cream and after dinner cruises.
It excels at everything except the after dinner cruises where it is too loud for my wife and some of the other women folk. I admit it can get a little old with me as well.

It currently has 3 ½” diameter system with ultramarine fiberglass mufflers between the risers and the tailpipes and plastic tips with no flaps.
The right side is a little louder than the left so I’m thinking the ultramarines are about done. They also leak a little water around the connections no matter how tight the clamps are.

I am thinking about replacing them with Rex Marine type Stainless Inline silencers.
http://shopping.rexmar.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=161102&Category_Code=silencers-inline-insert

The tips also leak a little and I am less than comfortable with any kind of plastic thru-hull. I spent a very long night a few years back with a 4” gas pump retrieving my friends’ cruiser that did its best impression of a submarine at a government wharf while we were in town having dinner.

Tip selection for 3 1/2:” outlets are somewhat limited and nothing with baffles. There are 3 ½” to 4” adapters you can buy, but I don’t think I have room for them. I took some pictures behind the gas tank with a digital camera to see what I was dealing with. If I yank the tank I want to be ready to make the change. Not wait for parts to arrive.

So I’m thinking about installing Hardin Marine’s 3 ½” Dia. Extra Long Straight Cut Exhaust Tip with an internal flapper.
http://www.hardin-marine.com/SearchResult~CategoryID~100.aspx

My thinking is that buy having the tip stick out 10” beyond the transom that at lower speeds the exhaust will at least be partially submerged in the wake and at high speeds it won’t. The concern is what kind of forces might be exerted on the pipe during maneuvering and will they affect the wake.

So if anyone has been experimenting with exhaust system mods; I would appreciate your input.

Thanks.
John

[tg0824SSVGG]

I don't know about your questions - but what a totally AWESOME photo!!!

[mapleleaf]

I agree, that photo is amazing.....there are lots'a spots uphere that look like that in the fall, makes me a proud Ontario resident!
My swimplatform sits a little crooked too, drives me a little nuts!
My wife isn't a big fan of the noise on our aft. dinner cruises as well, would be excited to follow your progress.
I found that like everything, the gas tank was harder to put in than take out! Filler neck was a bit tough, empty tank definitely makes it easier!

[rludtke]

Hi John,

I actually have experimented with my exhaust. See post https://forum.supraboats.com/showthread.php?p=15152#post15152.

I like the Fresh Air Exhaust System (http://www.freshairexhaust.com/), but I am not about to spend that much. So I am planning to build my own system simular to, but out of black plastic sewer pipe. I would mount it like I did the the plastic elbows (see post), but it will feature a cross pipe and two tees with outlets long enough to be well submerged at speed. I will brace it off of the swim step brackets to prevent it from lifting up under load. It is a really simple idea, and the sewer pipe has proven to be more than durable enough in my previous testing. The price is much much cheaper than the fresh air system. I just haven't gotten around to building it.

[SUPRA_ALLEGRO_LANE]

My recomendation is straight pipes from manifolds to the exit with single plate Super Traps. Its quite and keeps the power, keeps the ladies in the boat for a after dinner cruise too.

[87SunSportMikeyD]

You could try the rexmarine silencers but I don't think they really make a big sound reduction. I don't really think straight tips would make it much quieter. I have seen chrome exhaust tips that are downturned, which might help a little but still not a lot. Whenever the boat hits a wave or you turn, the exhaust will raise out of the water and it will be full volume. Also when you are driving at a faster speed the tips would still be out of the water IMO.

However, my Fresh Air Exhaust brings the exhaust down more than a foot. It provides well over 50% noise reduction and 90% exhaust fumes reduction at the swim platform when moving (even slowely). You can whisper over the motor, and hear the water spraying off the hull. I have to say it was worth every penny so far.

Rick I certainly am waiting to see how your experiment works out. However there is really a lot of pressure applied to the system in many different places. I really connot imagine any kind of plastic not cracking in several different places, like where the vertical support arms attach to the FAE and then to the braces bolted to the swim platform. Much pressure on the FAE there, mine has four braces. Then where the FAE connects to the hull there is much pressure up and down and the flexible 3.5" hose they provide is very very overengineered. I just can't imagine you'll spend a whole lot less in TOTAL because it is a somewhat elaborate system IMHO. I would not hesitate to call Larry Mann and talk to him for a bit because he would be happy to discuss his engineering process (he created it and designed and manufactures a new FAE custom built for every make or model or year of every brand of boat) and why he uses the materials he does.

I would be happy to post any up-close pics of the FAE you would like on my 87 SunSport.

Oh one more thing, are you sure it is safe to rev your engine that high??? I was told it is suicidal to go above 4600rpm and I would kill my motor since we have no rev limiter. My trans is 1:1 your may be different in which case never mind! :p

And Ontarion welcome to the club, thanks for posting and that picture is INCREDIBLE!!!!! I can see the sky and whispy clouds in the reflection off the windshield! I would love to see a high-res version of that pic, or maybe about 100 more!! :) :) Peace

[rludtke]

I can't get more than 4600 RPM at WOT with the 1:1 gearbox and stock prop with my boat. This equals ~45 mph top speed. Plenty fast for skiing/boarding- I rarely find myself over 30 mph when slalom skiing.

[rludtke]

Rick I certainly am waiting to see how your experiment works out. However there is really a lot of pressure applied to the system in many different places. I really connot imagine any kind of plastic not cracking in several different places, like where the vertical support arms attach to the FAE and then to the braces bolted to the swim platform. Much pressure on the FAE there, mine has four braces. Then where the FAE connects to the hull there is much pressure up and down and the flexible 3.5" hose they provide is very very overengineered. I just can't imagine you'll spend a whole lot less in TOTAL because it is a somewhat elaborate system IMHO. I would not hesitate to call Larry Mann and talk to him for a bit because he would be happy to discuss his engineering process (he created it and designed and manufactures a new FAE custom built for every make or model or year of every brand of boat) and why he uses the materials he does.

Hi Mikey,
The black plastic sewer pipe is greater than 1/4" thick at 4" diameter, and is pretty strong (mcuh stronger, less brittle the PVC). I think the mounting system I have derived is better then the FAE (If I am not mistaken, the FAE screws the pipe's flanges to the boat, like the supertrap disc plate). I plan to extend the centerline threaded rod that holds the Supertrapp disks in place. This rod is welded to a bracket welded to the inside of the exhaust pipe. It worked really well for supporting the 90 elbows I originally tried, but couldn't prevent the elbows from rotating. Turning the elbows to face each other, and connecting the elbows togather with a cross tube will fix that. Then I will use two Tee's to allow two exhaust tubes to rake back about 45 degrees into the water. To combat the water loads, I plan to brace the tube assembly with aluminum angles attached to the swim step brackets. These brackets will give additional lateral and vertical support.

What I am imagining will look something like the attchment.

Cheers,

[Ontarion]

The picture was taken in mid September. My favorite time in Northern Ontario. Warm sunny days, cool nights and mist on the water every morning. Best of all; no bugs. The cottage is a few miles west of Rousseau on a small chain of lakes just north of Lake Joseph. But the picture could have been taken on any of thousands of lakes in the Canadian Shield. Yes I have more. I guess I should open up a photo bucket album.


http://i536.photobucket.com/albums/ff321/Ontarion46m/100_0240b.jpg

The manual for the Pro-Boss GT40 says a maximum of 4800 RPM and not to exceed 4400 for constant cruising. As if? You would need a big lake. With 3 or 4 people in the boat the current set up runs 4800 and a tick over 50 on the Speedo’s. By myself, on water like in the picture it will spin 51-5200 but I don't know how fast as the Speedo’s top out at 50. So that is why I want to try the 14" prop to see if I can bring the revs down without sacrificing performance. It will have to wait another week as the prop puller I cobbled together from Princess Auto stuff didn't work. Now I have to buy a real one.

Maple Leaf; the swim platform may have a slight twist but the boat also has a slight list. I haven’t figured out why. It’s not retaining any water anywhere.

I don’t mind the noise at WOT. My first boat of my own was a hydroplane and I was 14 at the time. A combination of savings, birthdays, summer jobs etc. I pulled the exhaust cover plates off the side of the block on the old outboard too make it go faster. Now that was loud. I only kept the 4 corner bolts on the head because it had to come off every time I flipped the boat which occurred regularly. That was over 40 years ago and I should be at least deaf if not dead by now. I still like to go fast.

I am curious about the effect the FAE has on the performance of the boat and the wake. Over the years very small tweaking of trim tabs etc. has had profound differences on the performance of the boats I have owned. The FAE is kind of like dragging a lower unit behind the boat except a normal lower unit actually pushes the boat. It seems like a lot of force on the transom.

I work for a steel and pipe bending company but I don’t seem to have the time or ambition for DIY projects anymore.

I’m just hoping to tone it down a bit from say 25mph and under. Above that I can live with the noise to get the performance.

I chose this boat because it is a tow truck that can pretend it’s a sports car.

Thanks for the advice everyone. With the world going green, maybe there will be government grants to produce high tech solutions to quiet down our cast iron American V8 powered water toys.

[Ontarion]

I spent some time going through the website for the FAE. It looks like they attach directly to the plastic thru hulls that Supra uses. And I want to replace them with stainless thru hulls in any case when I pull the gas tank. I need to replace my blower hoses at the same time. Then if I decide to add an FAE later I will have something substantial to attach them to.

[Ontarion]

And if you are a skier this is water to die for.

http://i536.photobucket.com/albums/ff321/Ontarion46m/100_0223b.jpg

[87SunSportMikeyD]

Those pictures are SO AWESOME! Keep 'em coming.

The exhaust outlets are stainless steel. The FAE attaches directly to the transom of the boat. They provide you with flanges that fit over the exhaust outlets, and screw into the transom in place of the last supratrap ring. Then the flange is connected to the main FAE body by using stiff rubber hose similar to radiator hose or engine hose. There are two layers of this, tighened by many hose clamps. The main body of the FAE is three pieces, each piece connected by more stiff rubber hose and hose clamps. This is so the lowest point of the downpipe can flex, vibrate and also rotate to most efficiant position.

The FAE has no noticable effect on performance, speed or wake shape. It creates a tiny amount of spray behind the swim platform. Remember it is positioned directly behind the rudder, propshaft, strut, tracking fins and PROP which is moving so water is already very disturbed and churned up in that area.

I can post more pics otherwise I have many here:
http://photos.wakeboarder.com/showgallery.php/ppuser/35518/cat/500

[Ontarion]

Hi Mikey
There never were Supertrapps on my 96. Just ABS 3 1/2" diameter thru hulls screwed into the transom. If you look inside them there is some distortion. I am in the bending business and as such maybe a little picky. The thru hulls are probably the same ones SKIDIM sells only they don’t list 3 ½” in their catalogue. Go figure I don’t have a picture of them.
I do have a picture taken with a digital camera of the inside where they clamp to the tail pipe. You can see the reinforcing in the fiberglass for the outlet and the gas tank above. It takes long arms and a good auto-focus camera to get this shot.

http://i536.photobucket.com/albums/ff321/Ontarion46m/Picture017.jpg

[mapleleaf]

Those pic's keep getting better! I've done some work at Muskoka Woods on LK Rousseau and never get sick of being up there......Hamilton, Steel, Hmmmmmm.
If I was thinking of doing my own tower........could I get the tubing and some bend's done by you guys?????

[Ontarion]

Hi Mapleleaf
What do you have in mind?
Steel; Stainless; Aluminum?
You have a design in mind?
Our specialty is a little heavier but I'm sure I can help.

http://i536.photobucket.com/albums/ff321/Ontarion46m/100_3585.jpg

http://i536.photobucket.com/albums/ff321/Ontarion46m/100_3587.jpg

http://i536.photobucket.com/albums/ff321/Ontarion46m/000_0006.jpg

[mapleleaf]

LOL....I figured you might be doing some heavier duty work!
I'm in the very early stage of designing it, and have figured if I can get the top hoops bent, and the legs bent I'd be in good shape, I would rather bend's then miter's welded...
I was thinking about using .120 wall 2" and having it powder coated.....
I'm trying to combine a newdimension tower with the big Air Vapor tower....

http://www.bigairpylons.com/VaporTower.htm

http://www.newdimensiontowers.com/home.html

I wanted it to mount to the boat the way the Big Air does, and have the upper half look like the New dim., with all the cross bars....
Just had a friend offer up the welding yesterday, so I haven't done much in the way of measuring up or estimating.....
Gonna try and get a rough idea of cost and go from there....
Got any tools small enough for 2" LOL?

[Ontarion]

Hi Mapleleaf
Yes we do smaller stuff, but usually in volume because of the set up.
Your talking steel?
Try to stick with pipe sizes because the dies are more readily available.
A set of dies can be worth more than the boat.
1 1/2" pipe is actually 1.9" OD. 2" pipe is 2.375" OD.
Aluminum is the most difficult to bend. If it is tempered it likes to crack and if you anneal it, it becomes too soft and usually needs to be heat treated after bending to regain its strength.
Not to mention very few welders can actually weld aluminum properly.
Most of the bends are large radius so it probably doesn't matter.
The long radius is probably rolled and the top corners draw bent. The Big Air is a lot easier to bend than the New Dimension both in the quantity and style of bends. The New Dimension might be stretch formed.
What are you going to do for swivel mounts?
$800 seems like a decent price for the Big Air
$2300 for the New Dimension Zero Flex might sting a bit, especially after you add freight, exchange, brokerage, and taxes.

[mapleleaf]

You might laugh but Princess auto sells a plated knuckle joint on either end of 1" threaded rod....I met a guy who bought two of them cut them in half and had four he bolted to his boat, after he had threaded them into his tower legs....
I do like the price of the Big Air and it has nice lines, Just also like tinkering a bit....I deal with blade/knife set up and cutting charges for custom millwork all the time and about 50% of customer's shy away when they hear what the costs are!!!!!
Thanks for your input, it's a big help....
Don''t know that I'll go the same route as this guy did, but thought it was pretty awesome in a gearhead kinda way....

[87SunSportMikeyD]

Maple if you want something cheaper but still reputable check http://www.joystickpylons.com/

[saltare inverts]

Have you thought about wood. It is easy to find and you can paint to match your boat.

[mapleleaf]

Have you thought about wood. It is easy to find and you can paint to match your boat.

Did you have something exotic in mind??? Brazilian Walnut maybe??
This was a thread about exhaust.....LOL

[87SunSportMikeyD]

Hah now is when someone needs to post the pic of the i/o with the all-wooden tower. Shiz was beefy too!

[rickr]

These guys will work with you, product is made "In House" Talk to Brownie, tell him Donzi guy from Gatlinburg referred you.
http://stainlessmarine.com/myProducts.cfm?CategoryID=49|Exhaust%20Super%20Fla ps%20%2D%204%20%26%205%20S%2FS%20Exhaust

[Ontarion]

I am at the cottage on vacation so I decided to try the 14 inch pitch prop to see whether it would bring the revs down a bit. The old one is an OJ 13 x 13 cupped; with a couple of very minor dings. This one is a newly rebuilt michigan 13 x 14; no cup. It was a pain to change as the old one was just about welded on.
Anyway the results. I had 4 people in the boat and when I gunned it the tach shot almost immediatley to 5200 and I backed off or it would have climbed higher. I didn't even try to find the top end. At 4800 where I would would normally be doing 50 the boat was running around 44. There was still lots of throttle left but you can't use it. It also didn't seem to have the same snap.
I am surprised the cup made such a difference. Looking at the props side by side there doesn't seem to be a great deal of difference.
Tommorrow I am switching back.
Over the years with I/O's and Outboards I have allways found the perfect prop by borrowing from friends etc and you can try a half a dozen or more in an afternoon at the beach.
Trial and error is going to be a lot more difficult with an inboard.

[87SunSportMikeyD]

Have you called ACME or NettleProps yet??? They will answer all your q's and ID what you should be running. :) Trust me it is a fun call they are very smrty.

[Ontarion]

I finally got my Rex Marine inline silencers installed. One of the old fiberglass Ultra Marine mufflers was just a hollow shell; the other one still had the baffle but it wasn't long for this world either. So far I have only run the Rex's in the driveway with a fake a lake so its hard to tell how they will be. Definatley less of a blatty sound and more of a deep rumble. My 21 year old son said every engine should sound like that. I won't be back in the water until the long weekend so the inwater test will have to wait.
As for the look? Judge for yourself.

http://i536.photobucket.com/albums/ff321/Ontarion46m/rexmuffler2.jpg

And another view


http://i536.photobucket.com/albums/ff321/Ontarion46m/rexmuffler1.jpg

[mapleleaf]

just happened to be here for the big reveal.....
WOW those look great, hopefully they work as well as they look!
Where did you get them????

[Ontarion]

I bought them from Rex Marine
http://shopping.rexmar.com/
Their website is a little confusing and there was like zero feedback when I placed the order. However I ordered some stuff from SKIDIM the same day and both orders arrived the same day as well. No complaints there.
There is a Canadian company that sells them as well.
http://www.marinetoys.ca/mtoys/index.php
The price was a touch higher but import fees can be a crap shoot.
They both make you register before you place an order. But there was a certificate problem with the MarineToys site and then during the registration process they ask for your date of birth. WTF? No way I am giving it, so I sent them an email. No response so I went with Rex.
Very nice product. First class product and packaged like porcelain dolls.
We'll see how they work.

[mapleleaf]

Yeah feed back would be great, looking to quiet down those after dinner cruises....
Decided I'm buying a tower...already made....sooo much easier! thanks for all the help, those pic's were awesome!

[Ontarion]

Which tower did you decide on?
I was hot on the Krypt Pro Swoop. I like the swoop back to a single bar. I figured I could have it welded solid and powdercoated black and it would be as stiff as a custom and look a lot like the new Supra towers. Then I found out that all the Krypt towers are 56" in vertical height. On my Comp and probably on your Conbrio as well the mounting points are only about 20" above the floor. So total height 76". less 2 1/4" for the tube is 73 3/4". I used to be 6'3". I have lost about an inch over the years some of which has been leaving pieces of my scalp on low hanging objects and no hair to cushion the impact. Hang some speakers and I'll be crawling around the boat. I know monster makes a tall tower but it doesn't appeal to me. I have been meaning to write to New Dimension to find out what their height is. It will probably be a winter/spring project in any case. I'm working on a teak swimplatform at the moment and still deciding on what changes I am going to make to the exhaust thru hulls.

[mapleleaf]

Too Funny, I've got a willow swimplatform roughed out on saw horsres in the basement! I've also been meaning to check on the height , but I like the Big Air Vapor tower and am hoping they can make collapsable soon (winter/spring), style and price are pulling me that way. Lately I've been watching Ebay, it looks Airial (spelling??) Assault has been putting towers up for auction and some w/out reserve, have bid on a few, but am still hoping to get this done for about 1k before shipping. I may ahve 'til I'm back inMI at the cottage for delivery and install.
The Assault tower is similar to the Big Air, swooped with seperate tubes that mount to the boat kinda like New Dimension....
Check Ebay, the Assault's being auctioned are already black......
Been really busy redoing interior, almost half way, pic's to come.....:D

[Ontarion]

Well; I have my new Teak swim platform installed. Sort of.
It is the same width as the original and almost 4" deeper in the middle but without the grab rail it looks a little small.
I am thinking over the winter I will fabricate a new polished stainless grab rail for it. Something maybe a little meatier than the original. 1.050 or 1.35 diameter spaced about 1 1/2" off the platform.
The wood looks so beautiful and I am hoping the stainless will frame it as in highlight and not take away from it.

http://i536.photobucket.com/albums/ff321/Ontarion46m/Platform.jpg

The platform was made for a Ski Nautique 196. I had to cut the front curve away which shortened the overall lenght by 4" and narrowed the front about 2 1/2". That being said it looks very substantial and full width on the 196. I thought my comp was a narrow boat. The 196 must be very narrow.

http://i536.photobucket.com/albums/ff321/Ontarion46m/skinautique196.jpg


I had to route a bullnose on the front of the platform and 3/8" deep slots for the brackets to get the platform to fit under the fiberglass lip on the transom.

http://i536.photobucket.com/albums/ff321/Ontarion46m/Datto.jpg


The brackets had to be extensively modified. After I cut them down I had them sandblasted and they are shown here getting some new clear coat. The brackets were epoxied to the platform with westsystem and then screwed with epoxy coated screws. It is still removeable as a unit but the brackets can't be removed from the platform as the original could.

http://i536.photobucket.com/albums/ff321/Ontarion46m/Bracket.jpg

[mapleleaf]

WOw, that looks awesome!!!

[Ontarion]

I finally got to try out the new silencers today.
What a difference!!!!!!!!!!!!!!!!
I can now listen to the stereo or have a conversation.
It is still loud by comparison to an I/O or whatever, just not nearly as loud as before. Kind of like turning off the sub woofer. You miss it in some ways but are relieved at the same time.
And as far as I can tell the performance hasn't been diminished.
I'm still going to put the Hardin extra long thru hulls on that put the exhaust outlets 10" past the transom. If for nothing else to save my new swim platform from being pummeled by the exhaust at idle. The teak is stiffer than the fiberglass and you can really feel the vibration thru the boat from the exhaust rising up and hitting it at idle and low speed.
Anyway; If you want your boat to be quieter without being whimpy; I highly recomend the Rex Inline Silencers.

http://www.rexmar.com/page237.html

[Blackntan90]

Great pic's!! Thank you for sharing the pic's and the silencers- I have thought about the FAE for some time now, but maybe I will go with the rexmarine- they look fantastic too!!

[Ontarion]

I expect the FAE system is really quiet; it puts the exhaust down in I/O territory. An I/O would be like a 3 out of 10 and the Rex a 6 or 7. Still sounds like an inboard ski boat, just not as loud. Oddly enough the faster you go the quieter it seems to get. The sound changes pitch but doesn't get louder. At the lower rpm's the baffles probably aren’t working very hard but as you load them up with more exhaust pressure and cooling water they become more effective. Rex doesn't recommend them for engines over 500 hp which would make for a pretty deep breathing 351.
They are beautifully polished and certainly add some high performance bling that grabs everyone’s eye when you pop the doghouse.

[mapleleaf]

Looks like their prices aren't bad either.......