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wet exhaust

Old 03-05-2004, 07:22 PM
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magyarbacsi
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Default wet exhaust

I'm contemplating installing a WHH wet exhaust in my 48'' Challenger. One of the cons is that water may enter into the motor. Like in full scale boats, this is possible when you get a stern wave. To prevent this a flapper valve is installed either below the riser,or on the end of the exhaust tube when close to the water line. Are there such devices for rc boats and has anybody had problems with these tuned pipes re water in motor? I know they are not as efficient as the dry pipes, but the motor, a beefed up to 27cc Zenoah PUM will be enough to compensate. Besides, its a sport boat only and I want to be able to mount the hatch.
Old 03-05-2004, 07:40 PM
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ibuildstuff
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Default RE: wet exhaust

if its the same whh exhuast i have, the header comes out of the motor, goes down, then makes the bend, if anywater would get in, it would be little to none, and nothing to worry about, when you restart, itll blow it all out anyways


Jesse
Old 03-05-2004, 08:09 PM
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Aaronie
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Default RE: wet exhaust

Exactly what I was going to say. [8D] I have the WHH Wet Exhaust on my Homelite and I have had no water problems.
Old 03-05-2004, 10:14 PM
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magyarbacsi
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Default RE: wet exhaust

Thanks for the response. That eases my mind. Aarnie, dont you have a Challenger too? Maybe I have you confused with somebody else. If so, having a Challenger, how does it handle at speed, and what speed. I read on Jims board that a mod 260 will push it to its limit, but did not say what is the limit. With a stage 1 mod on a 230, I got 36 and that was with a Cooper quiet pipe that I modified to relieve back pressure. I only got 33 before the mod.
Old 03-06-2004, 11:53 AM
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Aaronie
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Default RE: wet exhaust

I don't have an Aeromarine Challenger, but I do have a copied (splashed) Challenger hull. Mine isn't as great as the real Challenger hull. They both look the same though. The only difference is that the copied hull has hooks and rockers down the keel.

I have a stock 260 Zenoah with a Cooper pipe in my splashed Challenger. I'm not sure how fast it goes because I don't have a GPS. I'm thinking it's going about 40 mph right now. The Challengers handle well until they go above 55 mph or so. Mine handles great, but it should be running a little bit dryer.

How did you modify your Cooper pipe to relieve the back pressure? And what is "back pressure"?

You said you had a 230 Zenoah, is that a 230RC or a 230PUM? I would love to see some pictures of your boat!
Old 03-06-2004, 05:52 PM
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magyarbacsi
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Default RE: wet exhaust

Aaron, the Challenger you have must be from forabucks, same as mine. It is non descript, black hull with red trim. Reminesent of the old rum runner boats. It has the G230PUM modified (exhaust timing and raised comp.) by Marine Specialties. The Challenger was a bit rough on the inside so I spent some time wet sanding with 80 to 100 grit. Its nice and smooth now and wont puncture my fuel cell, an IV bag set up. The hull seems straight and if I spend more time with the trim and tilt, I'm sure I can get a better speed, but I have to run with out the hatch because of the pipe. That is why I want to convert it to the WHH wet pipe. As far as the Cooper pipe, I by passed the side pipe, the one off set as it goes through a chamber then exits. This restricts the flow of exhaust gas, thus back pressure. Some of it is needed for the pipe to do what it is designed, but too much restriction wont let the motor breathe. I simply turned a piece of aluminum pipe in the lathe to match stinger to where it is "snug" in the internal stinger, cut a hole/ 1/2" at the apex of the cone in the back and extended the stinger insert out about 1" then welded it. Basically a typical pipe set up. Not as quiet, but not too loud. Quieter than a QD pipe,of which I have several, and seems to perform better then before. I also made it a solid clamp -on, as the way they are designed, the pipe would slide back and forth, changing the length to where water breached the inside seal and leaked inside the chamber. Had I not noticed it in time, I could of had water entering the cylinder, as the pipe was tilted upward. It is now a dry pipe, except for the water cooled manifold.

I also have Vern's 60" cat. Now that is a blast. A stock 260 and QD pipe, got 44.7 on gps. Not impressive, but looks cool as heck skimming on a glass smooth water. I even managed to blow it over twice, on the same day. I tried to run it loose and found out that the Thundercat, of which this is a copy of, runs best a little wet. I'm not a racer and 50 will be plenty for my skills

No pictures of the Challenger yet, only the cat. Will try to get it on the board.
Old 03-06-2004, 07:07 PM
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Aaronie
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Default RE: wet exhaust

Thanks for the information! Yes, I do have the forabuck Challenger. I can run mine with the hatch on because I cut part of the hatch and transom. But I don't because not enough air flows through. Oh, I also have a WTC header with my pipe.

Please try to get pictures of your boat up here. And I would like to see how you mounted your Cooper pipe.
Old 03-07-2004, 06:49 PM
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magyarbacsi
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Default RE: wet exhaust

check out my reponse to xplayer930, re the photos. Thats the cat. Re the Challenger, the Cooper is just standard, wrap to center header and pipe in the middle,similar to the cat. Extends to the back with out but with out the hatch. The cat on the surface was running too loose and did blow over. I had to look at the pictures to determine that, thats why I did it twice in a row on that outing. I live just above that bay.
Old 03-10-2004, 06:40 PM
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magyarbacsi
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Default RE: wet exhaust

Aaron I finally got the Challenger running close to the way it should. I expected the WHH wet pipe to slow it down, as the motor is a 230PUM with 1st stage mod. With the Cooper, my max was 36-37mph. With the WHH pipe, it souns better, got more rpm, 13,700, and 46.8 on gps. I could see it would not take too much more to get it too loose.
I read your thread about not tracking straight and I do have to hold the rudder slightly different at top from the slower speed setting. Checked my hull and looks straight enough. If there is a hook, its hard to see. I was thinking of replacing the motor with a 4 transfer port jug, but I'm leaving this alone as a fun boat. Will try for 50 when I get tabs on it, The waterwas a bit chopy, but the hull took it with a stride. The wet exhaust gives it a better sound too. Never got too hot even after several wot runs. I'll cut some windows in the hatch to give it some air and then run with the hatch.
Old 03-10-2004, 06:52 PM
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Aaronie
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Default RE: wet exhaust

I'm happy for you! [8D] I do not have a gps, so I don't know how fast mine goes. I wish I did have one though! I should try my WHH pipe with a Zenoah manifold on my 260 because I might go faster. My WHH pipe never got hot if water was going into it. I check my keel and it was straight, but I'm not sure about the hook(s). Really the last 9? inches should be perfect, because that's the only part of the boat touching the water.

I can't wait to get my boat back in the water!

I'm curious, what prop are you using? Thanks!
Old 03-10-2004, 10:43 PM
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magyarbacsi
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Default RE: wet exhaust

Octura X480, stock.I'm not much of a prop modifier though I've read a lot about trimming, cutting, etc...but i dont feel the need, yet, and at a minimum of $20. a prop...I dont want to take a chance of screwing it up.The two props I use most is Prather 275 and Octura 480. I have a trimmed down Octura 482. My 260 had a heck of a time spinning it. Odly enough, the Homelite 30cc had no problem with it in my Prather 46 V.

I've seen your boat on the posts. What pipe you have on it?

The Geko gps is actually quite cheap. I payed $95, but could have got it cheaper, $88. had I waited
Old 03-11-2004, 03:34 PM
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Aaronie
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Default RE: wet exhaust

Homelites have more torque than the Zenoahs, so that's why they can swing a "bigger" prop.

I just ran my WHH Sport (25cc Homelite, I tried to modify it a little bit ) with a ABC MW3 prop today. I was suprised it went so fast. It seemed to go faster than the Prather 275. And the boat also handled a little better.

I have 2 boats so far. My "forabuck" has a Cooper pipe and my WHH Sport has a WHH Pro Wet Tuned Pipe. I think I'm going with a Hanson or Midwest pipe for my Dumas Crackerbox.
Old 03-12-2004, 10:12 AM
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magyarbacsi
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Default RE: wet exhaust

Yes I know Homies put out more torque, but not the rpm. The best I got with my slightly mod 25cc was 9300. What have you done to the Homelite to modify and what kind of rpm you're getting. I have two, a 30cc and 25cc. There is a web site, I think Marty's boats,or even shark racing rc, re Homelite mods. I tried to enlarge the transfer ports on one of the 30cc and found out just how thin the cylinder wall is near the transfer ports. Went right through it. Parts for the 30cc are hard to find. Took months just to find the old style piston ring. I'm not to adventurous with props. I should probably try a few and maybe get surprised. Thats one area I have not explored a lot other then sharpen and balancing them. I dont want to spend a lot on props and know that some can run $ 50-$70. What is the diameter and pitch on the ABC prop and is that a 2 or 3 blade? Was there an increase in the rpm or speed and is that a lifting or non lifting prop, and... how much dinero?
Old 03-12-2004, 06:14 PM
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Aaronie
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Default RE: wet exhaust

I opened the exhaust, intake, and transfer ports a little bit. I have no idea what the timings are because I just grinded away. A friend once asked me, "How far did you grind?" And I replied with a, "I don't know." I don't know what rpms I'm getting because I don't have a tachometer.

All the rest of the information can be found here: [link=http://www.abcprops.com/]ABC Props[/link]
Old 03-12-2004, 07:46 PM
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Default RE: wet exhaust

Ya might want to check your coil as Homies ( some ) had coils that restricted the higher R's .

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