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How fast is your 496 Mag HO boat?

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Old 03-15-2010, 07:10 PM
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Originally Posted by live wire View Post
I was getting 71-72 out of my 288 open bow w/496HO with a stock28 bravo .
Your numbers seem off. Either you are light on RPM or WAY high on slip.

You should prop for 5K rpms. A 28P @5000, with 14% slip still works out to 76pmh.
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Old 03-15-2010, 09:59 PM
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I believe he meant stock 496 425 HP?
Yup, stock 425hp
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Old 03-15-2010, 10:06 PM
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Originally Posted by Dave M View Post
Your numbers seem off. Either you are light on RPM or WAY high on slip.

You should prop for 5K rpms. A 28P @5000, with 14% slip still works out to 76pmh.
Same numbers as above but at 79 mph, what does the prop slip percent show?
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Old 03-15-2010, 10:52 PM
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Originally Posted by Dave M View Post
Your numbers seem off. Either you are light on RPM or WAY high on slip.

You should prop for 5K rpms. A 28P @5000, with 14% slip still works out to 76pmh.
Kevin was originally running a 26 bravo 1 with those numbers. That should work out better. I think he confused it with a prop he is running now.
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Old 03-16-2010, 05:16 AM
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Originally Posted by MahopacMarine View Post
Kevin was originally running a 26 bravo 1 with those numbers. That should work out better. I think he confused it with a prop he is running now.
Must have been a senior moment .I'm spinning a 30 now or was last season and thought I only went up one size when we did the Whipple. But yes... I stand corrected stock was a 26.
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Old 03-16-2010, 10:36 AM
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Everyone needs to keep in mind that where you boat has a tremendous impact on speeds. You can only compare performances accurately when tested at the same location and time. As a comparison I had the opportunity to upgrade a 28 Nordic Heat and a 288 Sunsation to new 525 engines last summer. Testing afterwards at our local lake under very similar weather conditions on gps, same driver, netted the Nordic at 72 and the Sunsation at 73. Both had stock props. These boats ran low to mid 60's with 496 power. Take these same boats to where you guys are testing and they would pick up 5-6 mph, maybe more. So, please keep that in mind when reading all these results.




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Originally Posted by live wire View Post
I'm far from being any king of expert or trying to be an a**hole , but those numbers seem a little light. I think you might be leaving some money on the table. What does the boat weigh and what kind of RPM's are you running ?

I was getting 71-72 out of my 288 open bow w/496HO with a stock28 bravo .
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Old 03-16-2010, 06:26 PM
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I'm getting 76-77 mph(gps) no matter with a 27 mirage+ or a 28 bravo 1....Fully stock in fresh water on the Chattahoochee River.
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Old 03-16-2010, 08:44 PM
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I'm getting 76-77 mph(gps) no matter with a 27 mirage+ or a 28 bravo 1....Fully stock in fresh water on the Chattahoochee River.
Not to hijack, but how does the boat hook up and handle between the 2? Shoot me a PM if you would. I have a customer with a similar boat.
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Old 03-16-2010, 10:22 PM
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I wonder how far into the triple digits a pair would push a new Shadow 30? Too bad we will never find out , Boat was far ahead of the available power and drive packages of its time.
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Old 03-16-2010, 10:40 PM
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I saw 77 once early in the am by myself with less that 1/2 tank of fuel. usually 75.
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