X Dimension

[Chops]

I'm switching from Merc I drive to Bravo in my 18 2+3. Considering using IMCO lower which is 2" shorter. Worried about reducing X dimension too much- fears of poor steering, etc. I just read a post where CDMA will reduce X by 2" in a drive refit- this sounds cool to me. What is the magic X number?
Thanks in advance for any help-
Chops

[BigGrizzly]

Do it, there are many kits to make it longer.
It will affect handling, drive is not as low in the water, trim especially. Forrest and GeanD don't seem to have a problem, ask them. The Imco unit is more hydrodynamic. If I had a Bravo I would.

[This message has been edited by BigGrizzly (edited 01-03-2001).]

[BERTRAM BOY]

Chops,
I have a 2+3 that has a raised X dimension. 3 inches to be exact. It's hard for me to judge the difference between stock and a raised drive, because the boat was like that when I bought it. It seems to me though that it's harder to get out of the hole without cavitating the prop. It also seems that midrange throttle response is AWESOME..... also anything over 60 and she seems to get "squirrely"....but both my engine and drive are raised . I'm eventually going to bring it back down to where it's supposed to be. Hope this helps...
BERTRAM BOY

[GeneD]

We have an old post somewhere in the archives that talks about X dimension.
Some of us have raised X dimensions and we run with no problems. The less drag you have in the water, the faster you will run.
The magic number I can't remember. Check the old posts and you will find it.
Thing is, if you have the old Merc 1, and are going to replace it with the Bravo, you do realize the problems you will face right? First off, this is a good modification/upgrade, no doubting that. The big problem you are going to run into is that the Merc 1 gimbal and the Bravo drive are not compatible. You'll need a Bravo gimble. AND...the holes in the transom are not the same. No big problem there, if you are even the slightest bit mechanically inclined, you will be able to pull it off.
Using an Alpha drive would be your easiest way out of this.
X dimension modification:
Raising the motor/drive assy 2-3 inches would do it for you. I suggest 2.5 inches. The problems associated with raising the motor and drive assy are obvious I think.
Now...you talk about using the IMCO lower unit? If you have the money, that is the easiest way to raise the X dimension. And of course you are limited to the Bravo upper with that unit right?
But consider the cost of this mod.
$1855.00 for the case alone.
$3268.00 for a complete lower unit.
This, to me, is a ton of money to raise the X dimension.
The cheapest and easiest way to do this is to find an Alpha SS drive. In one fell swoop, you have a drive that fits on your present gimble (though your old gimble may need to be replaced or rebuilt), and you raise your X dimension by 2.75 inches.
These drives are hard to come by, but are available. In fact, if you were willing to lay out the money for the Bravo and the IMCO lower, you could afford a New Alpha SS.
GEOO has the source for those units, I am not sure of the price.
How 'bout it GEOO? Who makes those things?

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GeneD
007
Melbourne, Florida

[Scott Pearson]

Yes...Geoo. Do they make them still. I would be very interested.

Thanks (NJ)Scott

[Stromer]

Get the current X dim from Donzi factory. Talk to Steve (at Donzi) about how much higher you can go about the factory spec.

I have a Volvo Penta SX that is at 14 5/8" (approx) 2" above the Volvo HiPo engineers "stock" setting- this will not be the same for the black drives - but it will give you some ideas. Talk to the factory Donzi or Merc about the stock setting. It is usually based on transom angle - then go from there!

[GeneD]

Andy,
I have a great story about a prototype Sea Ray and transom angle. Near disaster.
Remind me to tell you about it when I see you in Orlando.

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GeneD
007
Melbourne, Florida

[Stromer]

Gene,

When is Orlando? I have been out for a while.

[Tom on Lanier]

Andy - check out the posts in "Talk to the Factory" re;Portofino, for the latest on that.

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Tom
"Tomahawk"

[GEOO]

Gene, Scott,
I called that outdrive company last month. They still show the drive on there web site but they stop making it last year. No part either. http://www.donzi.net/ubb/frown.gif GEOO

[Chops]

Thanks to all who replied, you guys are great.
Follow up: The Alpha SS is no doubt the best option, but will it handle HP over 400 and if so, does anyone know where a mortal like myself might get one? The search so far has been rough. Unfortunately, the Bravo does have a bunch of mod work to adapt to my boat but I'm prepared to do it to get the reliability. If I play buy and sell games on the used market with Bravo parts, I hope I can get into the IMCO lower for a net number less than retail. Besides, I'm prepared to eat mac & cheese from a can for a long time to get some wind burn.

[RickR]

Chops
If you plan on raising the X Dimension (smaller #) by raising the engine and drive package BEWARE of the hatch to engine(Flame arrestor and risers) clearence. You may need to install a hood scoop.
If your going over 300HP I'd use the Bravo, besides you'll prefer it's cone clutch.
I've heard the transom holes are very similar to the alpha(and Merc1)

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RICKR
mailto:riggerb@aol.comriggerb@aol.com</A>

[GEOO]

Chops,
Merc. and other companies make spacers in all different sizes to lower the drive. I would keep the engine in the stock height or lower the engine a little to lower the CG and get the shortest IMCO drive. If the drive ends up too short add a spacer to lower it. Ask IMCO if the sell spaces and/or if Merc's will work. GEOO

[Emmo]

Can you get this Bravo/IMCO setup in a LH rotation?

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Emmo mailto:emmette@emmette.comemmette@emmette.com</A>

[Scott Pearson]

Guy's
The transom hole is the same. Alpha VS Bravo.
The steel jig that you use to cut the hole in the transom is the same for both. Only the gimbel housing is different.

Get the bolt on JIG to cut the new hole its worth it.

(NJ)Scott

[GeneD]

Scott,
You are partially right.
The same jig is used, only the mounting holes are different for the two top holes I believe. Or it might be the two bottom holes? Or both? I forget, I have the jig and you are right now that I think of it. It's the TRS and the Alpha/Bravo that are different. But again, the mounting holes are different.

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GeneD
007
Melbourne, Florida

[RickR]

Emmo
The forward and reverse is in the upper unit on the Bravo. It's just a matter of the cone clutch going up or down. I believe the gears are straight cut.
You can see the detail in the microfiche on my 1/11 post "Microfiche"

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RICKR
mailto:riggerb@aol.comriggerb@aol.com</A>