SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: ROMPERSTOMPER on August 27, 2010, 07:30:38 PM
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What are the pros and cons in a jet boat. I'm thinking about it. a buddy will sell me the belt drive pump cheep. what kind of gains would I see? I know it keeps the oil out of the motor when not used=less drag on the crank. I know it oils the top end and bottom end seperatly and more efficently. Oil changes will be easy. the oil temp will be cooler. what else are the benifits?
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What are the pros and cons in a jet boat. I'm thinking about it. a buddy will sell me the belt drive pump cheep. what kind of gains would I see? I know it keeps the oil out of the motor when not used=less drag on the crank. I know it oils the top end and bottom end seperatly and more efficently. Oil changes will be easy. the oil temp will be cooler. what else are the benifits?
Staying away from the horsepower conversation (because RPM determines the gains and jets don't like a lot of RPM), there are some drawbacks to a dry sump IMHO....
The amount of oil for one.... $$$ :screwy: $$$
You need to be careful with flat tappet cams, rollers are a non issue, there is little to no splash to keep the cam alive at lower RPM.
The oil will be cooler yes, but that is not necessarily a good thing, you need to make sure things are warmed up before really hammering the gas, a lot like a Harley.
They eat up a buttload of real estate.
Plumbers nightmare. The plumbing is the expensive part, not the pumps.
The positives....
More clearance for the engine in a short D.L. application...
better oil control, as far as foaming, cavitation, and oil return to the "pan" becomes non issue...
More oil temp control.
More oil volume, that is never a bad thing except when buying the shit :screwy:
The horsepower argument is only valid when talking about 7500 or more RPM (my personal opinion) And I have yet to see a "fast" jet run more than 7,000 RPM. Vee drive yes, jet nope.
It would have an assload of cool, but in the end, crazy overkill IMHO
I have had a few Black Velvet and Coke Zero's so this may get revised later... :sly:
GT
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I have had a few Black Velvet and Coke Zero's so this may get revised later... :sly:
GT
Man, no shit. I've had a few Jack & Cokes myself, my vision is a little blurry, and I thought I read the subject of this thread as "Dry humping," not "Dry sumping." And so I almost replied to it as such until I read your reply (which made me re-read the subject title).
Thanks GT, ;)
LO
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^^^^^^ BAHAHAHAHAHAHAHAHA!!!!!!
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good job GT... you guys crack me up :)
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Lol thanks guys I'm crown guy myself.
I always run solid rollers in my projects.
Pluming is no issue for me, I have tons of left over hose and ends. make it myself
My peak hp is in the high 6000 rpm and will go to 8000 no problem when i squirt the 200 shot plus my impeller, bronze a-b is a little uder kill rite now. meaning it will rev high.
Have a pricey oil cooler already and I need more heat as I'm sittin rite now. I wasnt interested in it for that, mostly performace and longivity of my pricy motor. Its getting a rebuild as we speak, mostly bearings, a push rod, and a rocker. over-reved the bitch.
Ive done just about every upgrade known to man so far. Just want to learn more about this stuff. I only seen a few dry sump set ups in a boat, mostly vee-drives.
Thanks for the input!
What kind of hp numers? we talking about at 7000 rpm , ball park? I would assume 10 -50hp max?
I can get the 700 dollar pump for 200. pluming free or cheep, resevor not bad, oil pan ? unsure there never cheep. realstate is the main issue but can make it happen. Have a nice dooly 12 qt pan with baffles and a door now.
Knowing that should I go for it or still not worht it? This is a high doller high reving motor, top of the line top end, along with the bottom.
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With as little actual dry sump experience I have (mostly pull trucks with 500" injected screamers) I would say the gains would never eclipse the 50 HP mark, maybe closer to 20HP, the gains come from the vacuum effect from "pulling" the oil from the engine and the removal of parasitic windage, so in reality, the gains could be as high/higher with a good vacuum pump setup. That is if the engine has a higher than desirable crankcase pressure. (at 6000 plus RPM, I cannot see how there would not be).
Most of this is speculation and I have little to back it up.
Anyone else? Personally, I don't see it being worth the effort, but then again, I haven't tested it on a real situation either...
But it would have some cool points. :thumbup:
GT
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I do have a good vacume pump set up already :thumbup:
I think I'm over it then. Just more money I dont have rite now anyway. Especially If I dont really need it and theres not much perfomance inhancement In my app. Thanks tho good info.