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Re: Mhale00 & Raylar Kit
Originally Posted by Indy
Sorry Paul...I went through all my back issues and didn't find the one article I really wanted to save LOL!! I sent a note to PRA asking for the issue that it was in and I'll let you know after they respond.
Let me know if you hear back from them. |
Re: Mhale00 & Raylar Kit
Thanks for the insight on the Heat. We were talking about that last night and what to do to get one to run 80mph.
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Re: Mhale00 & Raylar Kit
Originally Posted by Nordicflame
Rage, here is some very reliable info...
http://www.offshoreonly.com/forums/s...d.php?t=107960 |
Re: Mhale00 & Raylar Kit
1 Attachment(s)
Originally Posted by Steve Zuckerman
Rage:
Keep in mind that all this begins and ends with the propeller. There is more performance to be lost or found here than on any other component on our boats. Propellers are our version of tires on race cars. The best chassis/engine combo won't work unless it can transmit it's forces to the pavement. It has always been my theory to build the "propeller to the boat", not build the boat to the propeller(s). Propeller technology continues to evolve, just as hull, engine, and drive technologies do. In some cases, propeller technology is catching up to drive and hull technology. Again, I would let Matt and Julie work their magic on your prop(s) before resorting to a lower XD. The other alternative, though expensive, is also preferable in trying/building a 5 blade. What the 5 blade does is add enough blade area, with that extra blade, to carry your hull, even with an elevated XD. An elevated XD, isn't a bad thing. It's a response by the factory to advancing drive and propeller technology. Also keep in mind that some of this is compromise.........sometimes mods that deliver extra top end, give up some bottom end, and vice versa. My best friend has a 29' Fountain with the same motor (575SCi) I have. Since I've done my recent round of mods, I can blister him out of the hole, and at pretty much any on plane punch, but he still has 2 or 3 MPH on me top end. His boat slips and cavitates coming on plane (like mine used to). His boat won't plane off without using tabs. Mine will. They are both great boats, but I've fixed my bottom end and acelleration issues and he hasn't. He doesn't care because he has great top end, and these aren't drag boats. My point is it's hard to have everything, even though we all want it. Good luck with your Rage and keeps us posted on your progress. Steve Attached PDF file explains my problem better than words. It seems to me something is wrong with my 2005 Nordic Rage setup particularly versus that of two other Nordic Rage boats, 2001 and 2003, with the same 496HO and Bravo1 drive. They both run 75+mph at~5000 rpm with a 26P Bravo (the 2001 is labbed the 2003 is unknown) and I run 68mph at 5000 rpm with the stock 26P Bravo under the best of water conditions. The difference is my rig displays 3 times the prop slip at WOT i.e. 14% versus 3%-4% slip. When one of these other boats runs a stock 32P Bravo ("with some nicks on the leading edge") after adding a supercharger the slip goes up to 11% but at the same time my rig with a 28P Bravo (labbed) jumps up to 20% slip. I also took a look at the before and after boat test data on a super charger manufacturer's web site. Out of 42 boat tests with everything from 24 to 42 foot performance boats with 21P to 30P props only nine tests were more than 10% slip. Only one 38 foot and one 40 foot boat test recorded slip at 20% or greater (21%). I assumed that the prop pitch posted was in fact the actual pitch of the prop. I am in a rare club! If you have any suggestions how I can get to the WOT performance level displayed by the two other Nordic Rage boats let me know! If you are aware of any additional detailed boat test data on WOT performance and prop slip I am also definitely interested in that as well! Thanks for all the help !! |
Re: Mhale00 & Raylar Kit
Hey Rage,
Sounds like your stressing a bit :( I'm not sure how you derived your slip numbers but just using the stated prop pitch and in reading order I get 8.5%, 7%, 20% and 28%. The 8.5 and 7 percent numbers are really like cat numbers especially when considering that Bravo props are actually ~1" smaller than advertised. But tachs can be and often are off. It's possible you may be off substantially with your tach and in turn you may have an engine issue. Can you have someone hook a scan tool to it? When my buddy's runs ~74 GPS at sea level, it's on or near the rev limiter 5150 with a 26 which is about 14% (10% when using true pitch) When running the 24 here at 5000 feet he sees ~68 GPS on or near the rev limiter with a 24 which is 14.7% slip (10% when using true pitch) A true 10 percent slip number on a V hull is considered very good and generally speaking the Rage hull is very good in that department. Dave |
Re: Mhale00 & Raylar Kit
Hey guys I'm using the prop slip calculator on the go-fast.com site to get my slip numbers. Aren't the formula's the same? I know that the tach can vary a little so I plug in 5050 rpm into the table. I knew I was at or over 5000 rpms because of the warning buzzer.
Rage, what are you using for your speed readings? Do you have a gps speedo or handheld unit? My factory speedo, a Gaffrig II at the time was erratic/malfuntioning/leaking after 10 hours. They sent me a new one and all was good. Just a thought ! |
Re: Mhale00 & Raylar Kit
Originally Posted by Nordicflame
Hey Rage,
Sounds like your stressing a bit :( I'm not sure how you derived your slip numbers but just using the stated prop pitch and in reading order I get 8.5%, 7%, 20% and 28%. The 8.5 and 7 percent numbers are really like cat numbers especially when considering that Bravo props are actually ~1" smaller than advertised. But tachs can be and often are off. It's possible you may be off substantially with your tach and in turn you may have an engine issue. Can you have someone hook a scan tool to it? When my buddy's runs ~74 GPS at sea level, it's on or near the rev limiter 5150 with a 26 which is about 14% (10% when using true pitch) When running the 24 here at 5000 feet he sees ~68 GPS on or near the rev limiter with a 24 which is 14.7% slip (10% when using true pitch) A true 10 percent slip number on a V hull is considered very good and generally speaking the Rage hull is very good in that department. Dave Your 1st 2 slip #s sound impossibly low, and the next 2 sound incredibly high. Then you have the lack of consistency between the props. If they are both B1s, even of differing pitches (and consequently RPMs), their slip #s should be more consistent. I would definitely get a shop tach, Merc or Rinda scan tool on your motor to see if any codes are showing up, or if your tach is off. What altitude are you running at? Your location isn't indicated on your avatar. Regards, Steve |
Re: Mhale00 & Raylar Kit
Originally Posted by Nordicflame
Hey Rage,
Sounds like your stressing a bit :( I'm not sure how you derived your slip numbers but just using the stated prop pitch and in reading order I get 8.5%, 7%, 20% and 28%. The 8.5 and 7 percent numbers are really like cat numbers especially when considering that Bravo props are actually ~1" smaller than advertised. But tachs can be and often are off. It's possible you may be off substantially with your tach and in turn you may have an engine issue. Can you have someone hook a scan tool to it? When my buddy's runs ~74 GPS at sea level, it's on or near the rev limiter 5150 with a 26 which is about 14% (10% when using true pitch) When running the 24 here at 5000 feet he sees ~68 GPS on or near the rev limiter with a 24 which is 14.7% slip (10% when using true pitch) A true 10 percent slip number on a V hull is considered very good and generally speaking the Rage hull is very good in that department. Dave Thanks for your and the others feed back and information. I truely appreciate it! I am a rookie and want to understand what is actually going on to get a handle on whether my Rage is correctly set up or not. The 2001 and 2003 Nordic Rage tests that I used for comparison are both from Power Boat Mag tests during those years. Their speed numbers are from radar /GPS. I have to assume that they got the rpms correct and correctly reported the prop used. I did use the true prop pitch for the Bravo1 props in the slip calc i.e. 25 true pitch for the "26P Bravo1", 27 true pitch for the "28P Bravo1" and 31 true pitch for the "32P Bravo1". Julie clued me into that aspect of the Bravo1 props a couple of weeks ago. Part of my learning curve. I have my Rage at a Mercruiser shop now to have the tach calibrated. That may well may be the answer. However if my tach is accurate then I am running 14% slip with a stock 26P Bravo1 and 20% with a labbed 28P Bravo1. Would that sound reasonable to you? My data is from several tests under good to ideal water and atmospheric conditions 3" to 6" chop, 60F temperature, 60% relative humidity, 5-10mph wind, at 916 elevation in fresh water. The loading was two people ~ in the console seats and full gas (56 gal / 330 pounds) with the 3700 pound dry weight Rage which is the same as the Power Boat Mag tests. I even obtained the labbed 28P Bravo1 from the same prop shop that made the labbed 26P Bravo1 for the 2001 Nordic Power Boat Mag test. My mph numbers are from a laptop gps unit that I confirmed as accurate with radar so I feel confident there. I am also asking the Mercruiser shop to check for any fault codes as well. Is there anything else I should ask them to check out? They do not have an engine dyno. Would the Mercruiser diagnostic software be able to give me anything useful to help sort this out? The fact is that two totally different Power Boat Mag tests conducted two years apart on two different bodies of water and two different Nordic Rages both with 496HO and Bravo1 drives, one an open bow like mine, gave 75.6mph at 5000 rpms WOT and 75.9 mph at 4950 rpms WOT. This would seem to be a relatively solid bench mark for that configuration. Am I missing some thing? If I was running 74mph GPS with my Rage at 5150 rpms I would be very happy. With Just my self and 50% gas in perfect conditions, 12" chop I once saw 69 mph at 5000 rpms with the labbed 28P Bravo1 (18% slip). I guess that is why I am stressing a bit. Sorry to ramble on! Any additional guidance would be greatly appreciated. |
Re: Mhale00 & Raylar Kit
1 Attachment(s)
Originally Posted by Steve Zuckerman
Yeah, what Dave said ;) : ................................
Your 1st 2 slip #s sound impossibly low, and the next 2 sound incredibly high. Then you have the lack of consistency between the props. If they are both B1s, even of differing pitches (and consequently RPMs), their slip #s should be more consistent. I would definitely get a shop tach, Merc or Rinda scan tool on your motor to see if any codes are showing up, or if your tach is off. What altitude are you running at? Your location isn't indicated on your avatar. Regards, Steve Thanks for the input. I answered your questions in my response to Dave. Let me know what you think. Attached is the web site data on the 42 boat tests I mentioned. It is interesting but does not have suffficient detail to hang your hat on. But still interesting. Thanks! |
Re: Mhale00 & Raylar Kit
Originally Posted by ComfortablyNumb
Hey guys I'm using the prop slip calculator on the go-fast.com site to get my slip numbers. Aren't the formula's the same? I know that the tach can vary a little so I plug in 5050 rpm into the table. I knew I was at or over 5000 rpms because of the warning buzzer.
Rage, what are you using for your speed readings? Do you have a gps speedo or handheld unit? My factory speedo, a Gaffrig II at the time was erratic/malfuntioning/leaking after 10 hours. They sent me a new one and all was good. Just a thought ! ComfortablyNumb, Thanks for you suggestions. I answered your questions in my reponse to Dave. Let me know what you think. Thanks! |
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