Ski Boat Forum
General Category => General American Skier Discussions => Topic started by: 56mulberry on March 21, 2011, 11:24:59 PM
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My fiberglass exhaust pipes that go from manifolds to transom exits are in rough shape. One is cracked bad at the 45 degree bend in it which I CAN repair if need to and the other is cracked where the rubber hose connecing it to manifold was pried off and damaged.
I am wondering if I got some marine exhaust rubber hose (3" ???) with the coiled wire reinforcment inside it, if I could just run that from the manifold to the exhaust port in transom....OR will it not bend well enough (i.e. too stiff) to angle down then flatten out under the floor there? My other option was considering using reinforced rubber exhaust hose in two sections with a stainless steel 45 degree fitting to make the bend where it nears the floor and flattens out...or could re-wrap the fiberglass pipes have now and reuse.
Anybody know or care to opine?
Thanks, DOUG
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Doug
There is one of the types of exhaust hose that MAY be able to make that bend, but I don't think I would even try. You could go the hose and SS 45 degree route, keep in mind you will need about 15 feet of the exhaust hose plus the cost of the SS pieces. This is also a noise issue (for some) as when the boat is moving the exhaust is an open style exhaust and will sound louder much like a powerboat with straight thru hull exhaust. It sounds good, but if you boat in areas with noise restrictions, it may cause you some headaches. I think your best bet is to either repair the old mufflers, or order new ones. I think they may be cheaper than the hose and SS 45 degree setup.
Brandon
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I have the ones out of my 85 advance, I have to look and see if they are ok. If you want them, just pay the shipping and they are yours.
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You say "mufflers" ? I only have straight fiberglass pipes from mu manifold to my thru hull exh scuppers--they couple to manifolds and the thru-hull fittings with 12" long sections of rubber exh hose--I do not have any mufflers that i am aware of. Got a pic? The noise is not an "issue" on our lake now but I dont want to be part of the problem that makes it an issue either. We have a lot of big open water so we are good here for now.
Did the boat originally have mufflers? What did/do they look like? I just have a 12" piece of rubber hose mated to a 3" fiberglass hollow tube (consistent diameter from start to finish) with a 45 degree angle in it where it hits near bottom of hull then straight back to the hull exits where there is another 12" peice of rubber hose to sleeve over both. This is on each side off left/right manifolds.....
Would love a pic of "muffler"
ALSo How hot would these get since the manifolds are water injected? If fiberglass pipe could take the heat I wonder if there is another cheaper like aluminum 45 bends I could use?
SOmebody wanto post a few pics of their diff exhaust set-ups for me? Thanks DOUG
Brnadon--I may be interested in your 45 degree bends anyways to fab this depending what they look like/and are made of???? thanks D
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Ron can chime in and set us straight, but my understanding is that what I have are mullfers and not just a piece of pipe. I had to repair a muffler on a mid 90's nautique and was told they use a different resin on these. That being said, I repaired it with std resin and fiberglass and we never had a problem. (Not to say doing the repair wrong is right, but that's how I was told to fix it.) As for using aluminum for the pipe or 45's, I would be worried about thinner alum. corroding or wearing out from any vibration or rubbing. There is heavier wall alum you could use, but then the cost will be approaching the SS prices. I believe this is the reason the fiberglass pipes/mufflers are used. I will try to lookup some more information. I know West Marine used to sell mufflers, fiberglass pipe, and fiberglass bends for exhaust systems, although you should be able to find it cheaper elseware.
Brandon
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If his 85 is like my 86 the elbows are part of the "muffler". Now, my manifolds are aluminum so I don't see any reason decent thickness 45's would hurt anything.
I hate shrinking pictures, but if you send me your email I send you a few shots of my exhaust.
If you could find some decent pipe, you could cut it at 45 degrees and weld it..... bet it would be cheaper and easier to come up with. Stainless pipe would work this way as well.
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Just looked a skidim.com, they have the 3" mufflers with the 45's molded in for $118 each brand new. I am pretty sure the SS 45's or alum 45's, plus the xtra hose you need to buy will cost more than that.
Brandon
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Don't forget to ask Ron or Dan for these parts if you are going to order, the least we can do for all their advice and help is to purchase from them when possible.
Mike posted while I was typing.
The aluminum will work, but it must be substantially thicker than say SS. The thicker wall pipe while still using the std exhaust hose will shrink the ID of the exhaust, possibly causing too much backpressure. Again for the cost involved, I personally would insall new mufflers and be done. There is something to say about why a builder/mfg builds, sells, and warranties their products the way they do.
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my mufflers were all cracked when i got the boat . so I removed them and repaired them with mesh/resin and extended the elbow (because it was all broken. probably from prying as well ) on one with a short piece of pipe and fiberglassed that in. Io fiberglassed them to the Hull in a couple of spots so they wont move around
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For many years ski boats used nothing but USCG exhaust rated corrugated hose & straight pipes, in the 70's everyone began added a fiberglass muffler in-line. By the mid eighties the race was on to get the boats as quiet as possible & you saw a number of muffler styles. All Advance models have mufflers, with only a few built with them deleted per customer request. If your exhaust exits over the transmission mounts using the corrugated hose will work. Some, especially newer models the exhaust exits under the transmission mount & requires a much tighter bend & the hose won't make that. Today the issue leans toward which is more affordable, the USCG hose is very pricey, & the fiberglass tube looks more affordable. I've seen old inboards with copper elbows, hate to price those. I haven't seen what others are offering in the aftermarket world I have an assortment of 3.5" stuff around here but no 3". The operating temps inside the exhaust usually never exceeds 200deg. But when you begin to lose water pressure from a failing impeller these temps can reach 1,000deg. burning the rubber, resins etc. The smell will alert all but the dumbest operators (wakeboarders) that there's a serious problem. Will it start a fire, well some wakeboarders discovered that a fire is the secondary problem to the two 3" holes allowing lake water in through the burned out exhaust pipes & that amount of water will snuff out any fire as the boat goes to the bottom. Yes the resins used by the muffler manufacturers is different than what you can get at Autozone, they are high temp, fire retardant resins, but again if you keep the temps inside at 200 deg. or less near anything will work.
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Now Ron.... that-there comment werent none too nice... poor ole dumb wakeboarders cant help it... :'( I for one am SHOCKED!!! :o I just-might-could report you to that-there Administrator fella and you'll have to buy us BOTH a beer at the Reunion!!! And, I aint talkin' no cheap ole Bud Light... I'm gonna go all high-dollar on ya and INSIST on a regular Bud!!! ;D
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OK--mine is just a straight thru piece of fiberglass pipe--no corrugation or baffles of any sort. It has the ends cut at approx 45 degrees and glassed together to form a down pipe the levels off along floor of boat after making the 45 degree bend. It is sleeved onto the manifold with about a 8-10" piece of rubber hose and on the exhaust exit end the same way.
On a whim ,I called the mufler guy in town whom I know well, and he told me he cuts 3" SS pipe off newer trucks every day so some one can put dual exhaust and or flomasters or glasspacks or whatever on them. He will give me the SS pipe I need as well as cut and weld it for me for the 45 degree bends. Then I could run some new rubber/re-inforced exhaust from the manifold to the SS bend and from the bend to the transom exit. Looks like I would need about 12' of it--about 6' per side depending on the length of my SS angled pieces.
That sound like a plan? Steel will be free so will just have to buy the hose and can get that through another friend who sells parts/boats here locally at close to cost.
Lemme know whatcha think....Doug
AND BTW Mike---you need to do a Google search for the "Windows Picture Resizer" utility and downlaod it (if you use windows...) It put s a really neat resizer feature on your mouse with a right click with a preset S/M/L pic option that only takes about 3 secs to resize--easiest thing you have ever used I promise--takes all the pain out of resizing pics for e-mail and internet use. 8)
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AWESOME! THANK YOU!
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Stainless tubing will work perfectly fine, will be loud. If they are doing all this for a reasonable cost you may also consider adding a 2" welded spud tube near the front of each tube facing each other & then you can connect them with 2" USCG rated smooth wall exhaust hose. This will act as an equalizer tube, proven to add a little HP, an old hot rodders trick, my boats from 96 up also had this feature, now I see others have copied it.
Now for the wagers, does anyone really want to test me?? Lets see if I gathered 10 traditional 3-event tournament skiers, and you choose 10 tournament wakeboarders & we did an IQ test, current event test, and boat maintenance test do you really think the wakeboarders would have a chance?? HMMM lets think about this the average 3-event tournament skier is a college grad, professional, knows how to buy 50K ski boats, then sell them 4 months later after putting hundreds of hours on them, then sell the same boat for 55K because they are meticulous about their boats. They also know that the water temp. gage is more important than the ballast tank fill gage. In 30+ years I have never seen or heard of a traditional skier keep running their boat while an impeller is self destructing. On the other hand I personally know of two customers (wakeboarders of course) who don't understand why their boats are smoking & "makin a badass stink" but think its cool. You see, you need to understand that I have been known to lend a wakeboarder some scrap rope from my shop for them to use as a belt to help hold their britches up..I'm old enough that I simply don't understand a guy wearing their shorts halfway down their butt. But if a pretty girl wants to do that I suppose I could make an exception....... ;D
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Since I am just replicating the current exhaust I guess it will be the same noise level as it is now?
RonT: Regarding the equalizer--(BTW: in road racing cars we call it an "X-pipe" or an "H-pipe" ...you prob already know that though) since the only part of my exchaust that will be stainless is the bends at the bottom of the downward sloping portion of the exhaust off the manifolds, can I put the crossover tube there? Or does it need to be further back toward the rudder area/rear of exhaust?
I imagine equalizer set-up exhaust would sound different then the "true dual" set-up of the current exhaust--I know straight pipes on a car sound different than straight pipes on a car with an H-pipe....
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Actually locating the crossover, H pipe, whatever we want to call it, the closer to the heads the better I found. The best was the "Whisper Drive" muffler I worked on with my muffler supplier at the time & it was right after the manifold down-turns & was a massive crossover. Sound waves will distort differently with different materials & shapes, if your just making the elbows from stainless you won't detect any difference. Now if the bulk of the exhaust is smooth hose vs. corrugated hose, vs smooth pipe, all will produce different "music"
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Ron, I guess you missed the part about "poor ole dumb wakeboarders cant help it..." ;D We cant really blame 'em for not knowing... all they have is $$... common sense seems to be a rare commodity these days... :)
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I knew Ron would chime in with his knowledge. My only advice is to make sure the exhaust pipe he (the muffler shop guy) gets you is true stainless steel and not a ss plated pipe. The plated pipe will rot out very soon. Other than that, you got a good plan.
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WEll in that case I think the best route would be to make a full stainless "H-pipe" that is attached to the manifold with a 8" piect of USCG exhaust rubber hose and has the crossover (in 2" "spuds" or spouts) halfway between the manifolds and the bend at the floor--and the bend could be welded right onto the end then just run rubber/re-inforced all the way back (which is only actually about 4' +/-) and attach to thru-hull at rear. I could then attach a 6-8" section of 3.5" plastic conduit (gray kind) along the stringer with hangers(the gray plastic kind) and stainless screws for a mount and run the flat part of exhhaust through it--since it rubber it should be abled to flex a little with boat movement and still be safely anchored there--maybe that is overkill but aseems tidy that way....
Added a couple rough sketches I did in Paint--make sense? Anyone see any problems doing it this way? Seems like it would be solid and durable as well as taking care of the crossover pipe issue all at once and relatively inexpensive since I can get the 2" and 3" stainless pipe from my muffler guy for free and have him weld it cheaply--I have the PVC for the sleeve/brackets laying here and the only real cost then would be about 8' (4 per side) of rubber /re-inforced marine grade exhuast hose to get from my "h-pipe" to the thru-hull exits out back.....
ANy problems foreseen here? thanks DOUG
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I like it. And I always like horsepower...... so when I pull the motor again Im gonna do the same thing (next winter). I got her built and running good, but never did anything about the way it looks. Wanna pull and paint it after the summer!
Thanks for all the info!!!
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Sounds good. I think the mfgs or maybe dealers used to wrap pieces of scrap carpet around them. I don't know if is was for sound deadening, abraision resistance, or just to get rid of scraps of carpet. It will look a lot cleaner the way you are suggesting.
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Be sure to take lots of pics and post on here... The cross-over pipe modification is something I'd like to do as well. ;D
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To keep the system "legal" you need to double clamp each and every exhaust joint. I've never heard of anyone using pvc pipe, my concern would be the pipe collapsing when at full temperature under the hose clamps.
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I knew I forgot something, the reason you see various things wrapped around the exhaust pipes under the center floors is for vibration, they tend to vibrate against the hull bottom unless suspended or insulated with something.
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Yes--hence my using the PVC only as a short 12" "sleeve" or bracket to suspend the pipe off the floor against the stringer--the PVC would not be exposed to any more heat then the rubber exhaust produces externally to the touch---look at my diagrams again. thanks DOUG