Imco Sc lower which one?
08-26-2017 | 08:42 PM
#11
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Joined: Jan 2002
Posts: 4,612
Likes: 7
From: ALTO, MI
With the prop down 7.5 inches I can't see how a shorty wouldn't help.
The fact that you don't have to trim much just means that your hull doesn't need much bow lift.
You are basically trimming to get the prop to suck in some air to loosen it up.
A shorty should cause a noticeable gain.
I still say to go with a -3 and shim it down IF you have to.
The fact that you don't have to trim much just means that your hull doesn't need much bow lift.
You are basically trimming to get the prop to suck in some air to loosen it up.
A shorty should cause a noticeable gain.
I still say to go with a -3 and shim it down IF you have to.
08-27-2017 | 07:54 PM
#13
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Joined: Jan 2002
Posts: 4,612
Likes: 7
From: ALTO, MI
How bad do you want to break 100 MPH.
7.5 inches down is real deep.
I had handling issues when my drives were that deep.
I raised the drives on my 34 Scarab with -2 IMCO shorties and it helped handling.
I used to have a 18 ft Glastron Carlson and I installed an Alpha SS drive that is 2.5 inches shorter than stock and gained 10 mph.
the next year I replaced the transom and raised the drive height another 2 inches and again gained 10 mph.
The drive on that boat was installed too low and the cavitation plate above the prop was actually 1/2 inch below the bottom of the boat.
Trimming the drive up for speed actually caused the cavitation plate to dig into the water and pull the transom down.
I am running a 4 blade Bravo prop on my Daytona but they are totally different boats.
I have the drive modified to allow more negative trim otherwise the boat would NEVER get on plane.
But as I said IMCO lowers are expensive so buy the shorter one and shim it down if needed.
The higher that you run the drive the more chance of blow out during turning.
Adding more cup to the prop can cure that problem and help with low speed planing.
7.5 inches down is real deep.
I had handling issues when my drives were that deep.
I raised the drives on my 34 Scarab with -2 IMCO shorties and it helped handling.
I used to have a 18 ft Glastron Carlson and I installed an Alpha SS drive that is 2.5 inches shorter than stock and gained 10 mph.
the next year I replaced the transom and raised the drive height another 2 inches and again gained 10 mph.
The drive on that boat was installed too low and the cavitation plate above the prop was actually 1/2 inch below the bottom of the boat.
Trimming the drive up for speed actually caused the cavitation plate to dig into the water and pull the transom down.
I am running a 4 blade Bravo prop on my Daytona but they are totally different boats.
I have the drive modified to allow more negative trim otherwise the boat would NEVER get on plane.
But as I said IMCO lowers are expensive so buy the shorter one and shim it down if needed.
The higher that you run the drive the more chance of blow out during turning.
Adding more cup to the prop can cure that problem and help with low speed planing.
08-28-2017 | 10:05 AM
#16
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Joined: Mar 2017
Posts: 23
Likes: 0
From: Albuquerque, NM
bigblockbill - Are you measuring from the bottom of the outer hull forward of the step or from the center pod.
That sounds a lot deeper than normal for a Daytona.
Stock mine was 2 inches lower than the lowest point on the hull.
I installed an IMCO neutral box with a -3 shorty and recut the transom up 1 inch for a total height of 2 inch above the lowest point of the hull.
That sounds a lot deeper than normal for a Daytona.
Stock mine was 2 inches lower than the lowest point on the hull.
I installed an IMCO neutral box with a -3 shorty and recut the transom up 1 inch for a total height of 2 inch above the lowest point of the hull.
