Best prop for tantrum with stock 454 mag with 365hp
03-21-2012, 05:01 PM
#1
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Best prop for tantrum with stock 454 mag with 365hp
Hey guys I want to get some input on what prop to go with. Last year I ran a 21p 4 blade which gave me a good mid range speed but on got around 4200 rpm out of it. Any other suggestions? I do most my riding in the LI sound so looking for something that is best for rough water.
03-21-2012, 06:28 PM
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Are you sure you have a mag motor or has your boat gained alot of weight? Your rpm's are way off from where you should be running (which is 4600-5000). Is your tach working correctly?
You might want to try a 19p Mirage + and see where that puts you. 4 blades typically reduce your rpm's too. Im guessing the 19p Mirage + will have you around 4800 which is where you want to be for a mag motor. If you dont have a mag motor then you are about right for rpms.
What is your top speed? I just ran your numbers in mercury's prop slip calculator and assuming 15% slip you are only running 47 mph. At 18% slip your down to 46 mph. Sounds low for a 25 foot boat with 365 hp.
http://www.mercuryracing.com/propell...calculator.php
You might want to try a 19p Mirage + and see where that puts you. 4 blades typically reduce your rpm's too. Im guessing the 19p Mirage + will have you around 4800 which is where you want to be for a mag motor. If you dont have a mag motor then you are about right for rpms.
What is your top speed? I just ran your numbers in mercury's prop slip calculator and assuming 15% slip you are only running 47 mph. At 18% slip your down to 46 mph. Sounds low for a 25 foot boat with 365 hp.
http://www.mercuryracing.com/propell...calculator.php
03-21-2012, 07:30 PM
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It's a 1996 with a bravo 1 drive. I thought for sure the rpm's seemed pretty low that why I was think to drop a blade. Is there any benefit to running a 4 blade over a three other then the whole shot and mid speed?
03-21-2012, 07:53 PM
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No...4 blades will get you on plane quicker and are better with cruising BUT they also come with more drag. A 3 blade will almost always be quicker for top speed and will increase your rpm's over the same pitch 4 blade prop.
Just verify you have a mag motor because a non mag shouldnt be running over 4600 rpm's.
Just verify you have a mag motor because a non mag shouldnt be running over 4600 rpm's.
03-22-2012, 02:18 AM
#8
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What make of 21" 4 blade???? Do you know the drive gear ratio????
Something sounds way off. You should be able to spin a 22-23 prop to the 4600-5000rpm range with a 1.50 ratio drive and 454mag.
I spun a 23 Mirage plus or 22 Bravo 1 to almost 5000rpms on my 24 Outlaw with a 454mag and the 25 AT is a faster hull.
Something sounds way off. You should be able to spin a 22-23 prop to the 4600-5000rpm range with a 1.50 ratio drive and 454mag.
I spun a 23 Mirage plus or 22 Bravo 1 to almost 5000rpms on my 24 Outlaw with a 454mag and the 25 AT is a faster hull.
03-22-2012, 07:54 AM
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We were not aggressive with the X-dimension back then. You need to go back to a 3 bladed Mirage. The pitch would have been a 23.
