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4 stroke boat and nos

Old 09-07-2010, 01:36 PM
  #26  
asmund
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Default RE: 4 stroke boat and nos

Oh yes, forstrokes can make as much power as piped two strokes. Check out this video of two similar planes, one piped two stroke and a YS120 (supercharged fourstroke) :

http://www.youtube.com/watch?v=dburR...layer_embedded

The whining high rpm twostroke never chatches up with the grunty fourstroke, it`s all about using the right prop, the power is definately there, only at lower rpm.

I own two YS engines, one .63 and the 110, they are brutale beasts[>:]

Edit: It was a 120, not a 110 as I first wrote
Old 09-07-2010, 02:08 PM
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amax
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Default RE: 4 stroke boat and nos

LOL,, Your a couple days Late and IN The Boat forum,, it's still being compared to 2 stroke Airplane Engines,, Not Marine Engines,,2 Completly Differant Set Up's and Power Curves.
Old 09-07-2010, 03:02 PM
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Default RE: 4 stroke boat and nos

I have to agree with Amax on that one. A four stroke aircraft engine will give more raw grunt at lower rpms that allow a plane to run a larger, higher pitched prop, providing more thrust than the two stroke of the same size spinning at the same RPM. When you consider that the average aircraft engine tops out at around 17K to keep the prop in a usable RPM range, this is totally different than a marine engine that spins up to between 25 and 30K for engines of .45 or larger and up to 35K for smaller. To take this one step further, an airplane engine of .20 to .25 will spin a prop size of around 8X4 to 9X6. A comparable marine engine would spin a prop of around 40mm in diameter with a pitch of around 50mm. You also have to remember that a four stroke normally burns fuel of under 10% nitro while the average boater runs a minimum of 25% and racers run up to 70%
Old 09-08-2010, 12:53 PM
  #29  
asmund
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Default RE: 4 stroke boat and nos

What`s with that attitude?? Have you understood what the thread starter is asking about?? Try reading the first post one more time[sm=lol.gif]
I`m fully aware that this is a boat forum and the engines I mentioned are aero engines, but for someone willing to make an experiment (like CEO) it should be possible to test out such a supercharged fourstroke aero engine in a hull. If you pay any attention to the video, you will discover that the twostroke actually is a DF (ducted fan engine) and rpm and HP of those are very high, similar to boat engines, can hardly be called a "average" 17K max aero engine at all Still the fourstroke leaves it behind. I only wrote this as information since I got the impression that there`s very little knowledge in here about the very powerful supercharged YS fourstrokes and aero engines in general it seems [sm=lol.gif] The starter of this thread was seeking info about fourstroke engines (which for the most part are aero engines) supercharging and/or NOS in general.

YS engines LOVES nitro and are run on 60% or more in competition by the way, since someone made a point out of this also[sm=lol.gif]

I myself run boats, planes, cars and helis by the way. So long[sm=shades_smile.gif]

Good luck to you CEO, it is always exiting to think and try something unusual[sm=thumbs_up.gif] but it clearly isn`t for anyone
Old 09-08-2010, 01:02 PM
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asmund
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Default RE: 4 stroke boat and nos

Sorry, doubble post. Please delete[sm=red_smile.gif]
Old 09-13-2010, 08:32 AM
  #31  
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Default RE: 4 stroke boat and nos

Several years ago I tried a Saito FA.40a in a boat project. I found some small flywheels and octura Kool Klamps on an auction site and retro fitted them for use. I installed 2 cooling clamps around the head. I took 2 small car flywheels and back filled them with molten lead to make them heavier. It took alot of weight to keep the engine running. The boat I built for it was 33 inches long and weighed 5 pounds. Not the best design for handling but it showed that it could be done. Here is and old video of me trying to dial it in. Good luck!
http://www.youtube.com/watch?v=hRU6LGsvuz8
Old 09-15-2010, 02:54 PM
  #32  
asmund
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Default RE: 4 stroke boat and nos

very cool[8D] Well done[sm=thumbup.gif]
Old 09-15-2010, 06:45 PM
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coriolan
 
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Default RE: 4 stroke boat and nos

Running good!
Old 09-17-2010, 08:53 PM
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Default RE: 4 stroke boat and nos


ORIGINAL: CEO

Has anyone tested a 4 stroker in a boat before? If so what were the results? I think it would be cool to have the 4 stroke sound in my boat. I understand that a 4 stroke wont have the rpm that a 2 stroke has but I figured I could add a little nos or a gearbox for coming out the the corners. I've also scored a free RB supercharger that was on my buddys mt2. Anyone think I'll have better results than he did if I put this on a 4 stroke nitro motor? Please no killjoys or hijacking. Please don't flame/rage or post any rude comments I'll have your post deleted. Thank you for understanding. Sorry to the people that dont do such things.

CEO
Here is a bit of information on four strokes in boats in case anyone doesn't know. O.S produced four strokes several years back. The first ones were 40 size and had exposed rocker arms, later on they made them in 40 size and .61 size as shown.Another little side note: You could also buy reverse ground cams for the os four strokes so you could counter rotate them in case the drives you were using did not.



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