Engine Shop
10-31-2006, 07:24 AM
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Re: Engine Shop
Originally Posted by RJBBC
Thanks Jeff, I am trying to justify the expense. The best I have come up with so far is less money to spend on the next power upgrade.
Are you thinking about supercharging? I have seen a few used procharger set ups for sale lately. Unfortunately, many of them were for carb set ups.
11-02-2006, 08:40 PM
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Re: Engine Shop
Originally Posted by Magic Medicine
Are you thinking about supercharging? I have seen a few used procharger set ups for sale lately. Unfortunately, many of them were for carb set ups.
11-03-2006, 05:02 AM
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Re: Engine Shop
Originally Posted by RJBBC
I am not sure what we will do. We may stay with our current short block, rebuild and supercharge. The other option would be to start fresh with a larger displacement NA motor. The good news is we have several years to think about it.
I would like to see my boat run faster, but I would rather have a bigger boat. I guess I will keep mine the way it is until I move up. You know you can never have too big of a boat for Lake Michigan.
11-03-2006, 09:07 PM
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Re: Engine Shop
Originally Posted by Magic Medicine
I would like to see my boat run faster, but I would rather have a bigger boat. I guess I will keep mine the way it is until I move up. You know you can never have too big of a boat for Lake Michigan.
11-04-2006, 07:16 AM
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Re: Engine Shop
Originally Posted by RJBBC
A smaller boat is easier on the retirement fund and takes more driver skill in rough water.
I hear ya, but NOTHING BEATS A CIGARETTE!
11-26-2006, 03:58 PM
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Re: Engine Shop
Originally Posted by checkmate454mag
Rob,
I dont understand those numbers either. More power to you if they are right but the facts are below.
(((pitch x rpm) / ratio)) / 1056= theoretical speed
Then add in slip.
your numbers are as follows, assuming a 1.5 ratio drive..
24.5 x 5000= 122500
122500 / 1.5 = 8166.66666
8166.666 / 1056 = 77.33
So 77.33 is theoretical speed without slip factored in. If you are actually running 72.3 then your slip is only 6.5% . That would be great . Unfortunetly, most likely impossible. Here is a for instance.. I am running a Hydromotive P5-X and am getting 9.5% slip.
I dont understand those numbers either. More power to you if they are right but the facts are below.
(((pitch x rpm) / ratio)) / 1056= theoretical speed
Then add in slip.
your numbers are as follows, assuming a 1.5 ratio drive..
24.5 x 5000= 122500
122500 / 1.5 = 8166.66666
8166.666 / 1056 = 77.33
So 77.33 is theoretical speed without slip factored in. If you are actually running 72.3 then your slip is only 6.5% . That would be great . Unfortunetly, most likely impossible. Here is a for instance.. I am running a Hydromotive P5-X and am getting 9.5% slip.
, Hallet 255 Open Bow 75.3mph@5000rpm=77.3mph theoretical speed or 2.6% slip, Laser 25 Fury 77.1mph@5200rpm=80.4mph theoretical speed or 4.1% slip and Shockwave 25 Tremor 79.8mph@5300rpm=82mph theoretical speed or 2.7% slip. The above four boats ran 525EFIs with Bravo XR drives with 1.5:1 gear ratios with Mercury Bravo One 15 1/4" x 26" props. Any ideas on what's going on? Go Bears 
Last edited by RJBBC; 11-26-2006 at 04:17 PM.
11-30-2006, 08:14 PM
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Re: Engine Shop
Originally Posted by checkmate454mag
Yeah, magazines lie like hell!! How can they claim to be on the positive side of slip???
11-30-2006, 10:20 PM
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Re: Engine Shop
While I have never had the opportunity to test in fresh water, I have not heard of any measurable difference in performance between fresh and salt water. Altitude is another story. As anyone would expect, the loss of horsepower attributed to altitude only increases the higher you go. I am sure that it exists, I dont know of any actual formulas that can measure the loss at specific altitudes.
