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98shovel
01-02-2007, 10:07 AM
looking for some opinions on running alum. flywheel verses steel in a i/o application any draw backs or bennifits

Pismo
01-02-2007, 07:41 PM
Corrosion if salt.

DON N.
01-03-2007, 05:47 PM
Steel For A Boat.

98shovel
01-03-2007, 07:06 PM
why everbody says steel but know one says why corrosion can be delt with so its not an issue

DON N.
01-03-2007, 09:24 PM
If Your Boat Gets Air At Speed And Revs Will Go Up Quick, You Could Damage Your Engine, With An Aluminum Fly Wheel.

98shovel
01-03-2007, 09:41 PM
thats what rev limiters are for

mphatc
01-03-2007, 09:56 PM
Revs climb faster with the lower rotating mass, but they give you no more power. It will only effect the time to redline . . which in a recreational boat is not important and will have no measurable or noticable positive effect on performance.

Atleast this is how it was expalined to me by the shop that now does my machine work, and has been building some serious marine and offshore race engines . .

Mario

98shovel
01-04-2007, 12:18 AM
mario,thanx for the reply could u ask them if theirs any reason not to run one motors out getting more head work more cam ect we use them in cars all the time but my machine shop doesent know about one in a boat
patrick

Walt. H.
01-04-2007, 02:28 AM
We always preferred a heavy 40-lbs steel billet flywheels in our drag cars for a better launch off the line unless the engine was in a very light car, and I would say the same benefit would be had with a heavy steel flywheel in a boat to maintain rotating rpm's when you catch air and upon re-entry the prop hits back into the water and wants to lug the motor down abruptly.
The centrifugal rotating force of a heavy flywheel will help maintain a steady rpm, just as what the flywheel was designed to do.

This could be a good topic to kick around and see where it goes?:smash: :crossfing
I guess there's pros & cons to everything, maybe a light flywheel might be easier on the stern drive and promote longer life?

Walt

turbo2256
01-04-2007, 06:51 AM
I have automatic transmissions in my boat just flex plates. Dont think I notice much differance. If anything prop gets air arm perty much pulls back on the throttlle and usually realize it about the time I begin to sinc the prop speed with the boat speed for re entry. I never remember anything about maintaning a prop speed airing the prop just backing off the throttle and getting back on it on reentry. Just accelerating decelerating dont see a need for an energy storing flywheel. Titanium props also reduce the rotating mass woud be nice to have a couple of those costly items. Could it have more to do with aluminum flywheels are costly too.

BigGrizzly
01-04-2007, 08:38 AM
Walt is correct. The one thing people forget is after planing the boat gets heavier not lighter. Every time you hit a wave, with less flywheel affect the boat could slow down. In the old racing days we use to weight the prop for that reason. the other thing is SS props are significantly heavier than Al props but faster The flywheel affect is more of a benefit than a loss. If you had a drag boat with big power it and glass smooth water may help. Turbo you have auto trans do you have a torque converter? If you do there is your flywheel. Believe me if it was worth it I would have it.

mphatc
01-04-2007, 09:46 AM
Patrick,

Please clarify, as you typed your reply I'm not sure what the question really is . . . . :confused:


Mario

98shovel
01-04-2007, 09:49 AM
the advantage i could see for the hole shot becouse rpm would increase faster but my concern was once on plane wuold it have a neg. effect on maintianing steedy rpm through the water.
ss props from my understanding out perf. alum. becouse of less deflection on the blade .
but props theirs a nother topic kinda like camshaft selection standard blade or clever 3/4/5 blades lets see where that goes

turbo2256
01-04-2007, 04:57 PM
Turbo you have auto trans do you have a torque converter? If you do there is your flywheel. Believe me if it was worth it I would have it.

Not torque converters they are direct drive Powerglides. Setup like a sprint car they will handle about 1200 HP or better. Would like to know about running a converter. Know anyone running one in a boat? These things are never completely out of gear in neutral there pushing forward kinda like a clutch fan. There isnt enough drag as in a car to stop them from spinning. A bit of a pain to launch and retrive the 33' boat by myself. Manuvers around the dock and stuff in low gear. Freaks people out when I rev it up a bit and still slowly manuver LOL. Have gone up onne ramp a bit to far once in some bad conditions no dammage. Scarry.