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air cooled nitro in a boat

Old 05-11-2016, 02:37 PM
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spalmer
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Default air cooled nitro in a boat

hi im new to this forum i thought i would ask for some ideas from people im in the process right now on trying to get a hpi 4.6 mocked up in my old proboat shockwave 36 now i heard from people that you can do it as long as the heat sink can get air and mix castor content to get 18% cause that what boat fuel is now the only thing im trying to figure out is it going to work ive already spent alot of money on parts to try and get it to work i bought a 50mm fan the ones they use on esc and motor but im gunna try it without the fan first cause ive heard from people that they get way to much air flow and then they ended up cutting off some of the heat sink fin im try and use the stock boat tuned pipe and im using a clutch off of the thunder tiger outlaw 7.5 vortex hobby still have all the componets to the clutch if you guys can point me in the right direction on witch i should use the fan on what prop i can spin i might try a octura x445 but i dont know and ive heard people say they had to do alot of work on the right tune pipe length and how to figure out how to get the right length if you can give me advice thst be great
Old 05-12-2016, 06:45 AM
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Hydro Junkie
 
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Three things:
1) Is this motor a car/buggy or an aircraft motor? They have different requirements for installation and cooling so knowing which you are using would help since I'm not familiar with HPI products
2) You can use an air cooled motor as long as the heat sink is exposed to the air above the deck line
3) Lose the clutch. Your motor is going to need a constant airflow around the heat sink and sitting still won't be good for it. Clutches are also a power thief and, in general, more problems than they are worth.
Old 05-12-2016, 10:33 AM
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I'm no expert but I think you are going to need it water-cooled since boat engine interiors seem to have very little air flow.
Old 05-12-2016, 03:48 PM
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spalmer
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the motor is out of the save x 4.6 the monster truck big block its not a buggy or out of a nitro car as far as the cooling goes i do have a 50mm fan they use on esc but bigger than those the fan with blow constant cool air on the heat sink while its running and also another advange on the boat is that theres air flow hole on the hull

Last edited by spalmer; 05-12-2016 at 03:53 PM.
Old 05-12-2016, 05:24 PM
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Ron Olson
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OK. I've put air-cooled nitro engines in a few boats so I've been there.
With the Shockwave you won't need the fan but you will have to leave the hatch off. Normally I'd tell you that you don't need all of the heat sinks but in this instance I wouldn't cut any of them off.
Consider that the engine will have a lot more exposure to cooler air than under a Lexan body.
The Thunder Tiger clutch is one of the worst ever made as it has a huge problem with the bearings. If you decide to keep it, stock up on those but I'd highly suggest going with a direct drive.
Try the Octura M-445, not the X as it's a better prop.
Pipe length. Start it off at 10" and go from there. Measure from the glow plug to the widest part of the pipe following the path of the exhaust.
If you're using the stock exhaust from the Shockwave, port-match the header to the exhaust outlet on the engine. There is a lot of free power lost there as it's choking it off.
Old 05-12-2016, 07:18 PM
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spalmer
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ok im a little lost on the exhaust i adapted to savage 4.6 header to a rubber coupler and then the shockwave header on the other side of the coupler then to the exhaust on out and i wanna use the hatch cause i dont want no water inside i figure if i cut a hole in the hatch around the top of the motor and mount my fan behind it and since im boosting my oil content i figure it wouldnt overheat now do you think the octura m 445 is the right prop or a good starting place i just dont want to put a prop on there to where it over revs now for the exhaust can i use the stock savage exhaust header and pipe and then use some vaccum hose and clamp it to the exit hole on the pipe and follow it out to the exit on the back of the transom casue i still wanna use the stock exit hole on the transom

Last edited by spalmer; 05-12-2016 at 07:27 PM.

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