Minx 20 with New Imco 2" Shortie
Hi. Saw some of these past posts and wanted to ask if anyone had issues when they put the 2" shortie on your Donzi classic. I am getting major slippage/cavitation since I put the shortie on. I have a small supercharger on a 350 SBC. Should be making around 400hp but still questioning that. I tried a Mirage 21p and a Rev 4 blade 19p and both where very bad. Boat handled real sloppy too. I do have a Rev 23p that I could try but wondering if something else is wrong. Appreciate any info you have on this..
check drive alignment and 1" spacer
Quote:
Originally Posted by
MinxRaider
I am running a Bravo drive with the 2" shortie (replaced the original Alpha at the same height). The standard Bravo was close to 8" below the bottom so I assume I should be around 6" now. Unfortunately didn't get a measurement before the boat went in the water. Just seems to have a real bad effect overall and not sure a prop can fix it.. Putting tabs down made things much worse..
A Bravo drive is a little longer than an Alpha and I'm guessing that a Bravo with 2" shorty is similar to an Alpha SS in length.
I would not think 6" below is too high but you could try a 1" spacer.
I would check drive alignment and make sure your steering is tight/not sloppy.
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Update Mercury Racing Max5 28p
Another update and improvement. I tried a Mercury Racing Max5 5-blade 28p prop and without really trying it ran 82.5mph @ 5,300 rpm, about 12% slip. I only trimmed it out about half way. The Max5 seems to really like to be trimmed out, you can really feel the boat respond to trim, but I didn't want to push it too much until I install Latham dual ram steering over the winter. The Max5 runs more efficiently (less slip) and also handles nicely. It steps right up on plane without tabs and turns nicely. This is my best prop so far. I hope this is helpful to someone out there.
http://www.mercuryracing.com/boat-pr...erndrive/max5/
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For posterity - 88 mph Merc Max5 29p
For posterity, I ended up liking the Mercury Max5 29p best. 88 mph at 5,400. We're done :)