Daytona setup issues going from iron block to aluminum motor
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Daytona setup issues going from iron block to aluminum motor

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    Default Daytona setup issues going from iron block to aluminum motor

    1978 daytona 19' . Went from iron tall deck to 9.850 aluminum. Anyone out there went from an iron motor to an aluminum one with more power. Tried to post video but it wont let me. It goes from overcharging to running out of water with minor adjustments. Cant seem to complete a pass without it bucking. I would think this new lighter motor would like more shoe, but the opposite, I had to pull some shims out cause intake pressure shot up till ass slowed down & water finally burped out the back. Motor sets 30" from transom , Does it need to be moved forward ? I'm loosing my patiance. Help....anyone ?

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    Senior Member sleekvino's Avatar
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    is this a flat keel boat? anything been done to the bottom?
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    It's hard to give setup advice. Too many variables to offer up details. But typically lighter engine means move fwd and considerablly more power means move fwd.
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    Quote Originally Posted by sleekvino View Post
    is this a flat keel boat? anything been done to the bottom?
    Boat has drop keel.

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    Default Lighter setup

    Quote Originally Posted by cpjet View Post
    Boat has drop keel.
    When ever you lighten up the boat whatever you were getting away with the heavier setup will become more pronounced when the boat gets lighter. When we went from Old Skool to Fbomb I told Mike this boat is considerably lighter and a slight over charge is going to feel alot more severe. If you are over charging early in the pass it is overcharging all the way down the track. Do you have any means of checking suction pressure? If so where is your pressure pickup?

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    Quote Originally Posted by Infomaniac View Post
    It's hard to give setup advice. Too many variables to offer up details. But typically lighter engine means move fwd and considerablly more power means move fwd.
    Info , that's definately what it's starting to look like. I think I'm gonna try 2* of down wedge & see if I can run 800'. In the video I had either 1/2*DN or 1 1/2 *DN wedge, cant remember without my notes from the shop. If that dont work , I thought about puting a 150lb passenger in the boat & see if it stays hooked up ? Gonna try & load video again thru youtube.

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    Hey CPJet...glad to see you made it over from the Bullet....
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    steelcomp was here
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    Quote Originally Posted by cpjet View Post
    Info , that's definately what it's starting to look like. I think I'm gonna try 2* of down wedge & see if I can run 800'. In the video I had either 1/2*DN or 1 1/2 *DN wedge, cant remember without my notes from the shop. If that dont work , I thought about puting a 150lb passenger in the boat & see if it stays hooked up ? Gonna try & load video again thru youtube.
    IN my limited experience, and I could be all wet here (pun intended)...more down wedge is going to want to lift the transom. If you have an overcharge condition, this may make it worse. Up wedge tends to lift the nose, but it also drives the transom down. Point being, I don't think you can simulate moving the engine forward by changing the nozzle. My guess is you're going to need some keel/opening changes to do this right. Is this a standard intake?
    Last edited by scott foxwell; 07-14-2012 at 09:23 AM.
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    Quote Originally Posted by greg shoemaker View Post
    When ever you lighten up the boat whatever you were getting away with the heavier setup will become more pronounced when the boat gets lighter. When we went from Old Skool to Fbomb I told Mike this boat is considerably lighter and a slight over charge is going to feel alot more severe. If you are over charging early in the pass it is overcharging all the way down the track. Do you have any means of checking suction pressure? If so where is your pressure pickup?
    What psi (high or low) would be considered "overcharging"?

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    OK , here's a link to one video. Dont know why the bottom half of screen is green. On my puter I view it with windows media player & when I click full screen I can right click & slow video way down to see step by step. If you look at it at 9 seconds frame by frame you see nose get too high. Again dont know wats up with the youtube video ?
    https://www.youtube.com/watch?feature=player_detailpage&v=UfuOCEF3iT8

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    I went from an all iron BBC to all aluminum LS1. But...with substantially less power than what you have (330 hp BBC to 550 hp LS1).

    I spoke a lot with some of the experienced 21' tunnel guys when I made the switch (mine is a 21' Liberator). My question would be what shoe are you running?

    I was told these boats liked 2* backcut shoe...but potentially with the lighter engine I would do better with a 1* backcut or flat shoe. So far for me the 2* seems to be fine...but I wonder if a shoe change could help your issue?


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    What's the difference in the weight?? How much did you lightin the boat??? And is the engine in the same spot as the iron was??
    Last edited by TNYoungblood; 07-14-2012 at 10:49 AM.
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    Move the motor to at least 34" from the transom. You need to know where the nozzle angle is in relation to the bottom of the boat. A half degree or one and a half degree wedge means nothing you must know the nozzle angle. A good starting point for your nozzle would be around -2 degrees. What type of shoe are you running flat, tapered, back cut?

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    Quote Originally Posted by Red Rocket View Post
    Move the motor to at least 34" from the transom. You need to know where the nozzle angle is in relation to the bottom of the boat. A half degree or one and a half degree wedge means nothing you must know the nozzle angle. A good starting point for your nozzle would be around -2 degrees. What type of shoe are you running flat, tapered, back cut?
    Good point. Got to get the baseline established; start with the basics.
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