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Need opinions on prop/gears

Need opinions on prop/gears

Old 09-30-2019, 04:05 PM
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Default Need opinions on prop/gears

I'm kinda at a crossroads with tuning in my boat...

28 Nordic heat with estimated 750-800 hp

Part of my build was to put a shorty lower unit on it and I found a great deal on a sportmaster lower on here, purchased it, and put it on..now here's the kicker..it was a 1.36 ratio as opposed to my 1.50 I had prior

My thoughts were that with the extra horsepower I might be able to get away without a prop change with the gear change which is slightly true...here's my findings...

26 pitch bravo....5000-5100 rpm trimmed to the moon 81 mph chine walked BAADDD
28 pitch bravo(was on the boat prior to build)...4800-4900 also trimmed to the moon 79-80 bouncing right on 80
Labbed 30 pitch bravo....45-4600 trim didn't matter too much 72-73 mph and felt like I was dragging an elephant obviously too much prop

I'd like to see RPM's in the 56-5700 range WOT as the motor says that will be peak HP with my current cam which is fine because it makes me a little uneasy twisting a blower motor much higher than that....so...options/opinions

1. Swap lower gears over the winter back to 1.50 and hope that the 3 current props I have will put me in the ballpark
2. Find/buy a 24 pitch bravo and hope it brings my rpm's up where I want them and have it labbed to tweak it in
3. Have the 26 labbed and see where that puts me

My concern is the amount of chine walk I saw on the 26...the 26 and 28 are both box stock unlabbed props and there was a night and day difference between the two as far as handling goes...so I'm wondering if the smaller pitch is causing me some issues or if it's because I have to trim the thing to the moon to get the heavy nose up with such a big single engine boat

My research has found that the hydro p-5x is the prop of choice for other Nordic heat guys however those reports were on stepped hull heats and mine is the non stepped pad version of the hull so I don't want to drop that kind of coin on a prop just to try it especially until I get a better idea on what pitch I would need....also hydromotive props are getting harder and harder to get due to some kind of issues at hydromotive....next step would be either herring or maximus but again until I get the motor in the RPM range I'm looking for I really don't want to make guesses on what I would need pitch wise so I think taking the variable of switching to a 5 blade off the table right now I'll just stick with bravo props...

What's everyone's thoughts/opinions??

Thanks!!
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Old 09-30-2019, 08:08 PM
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I would try a 25 Mirage or Mirage + to get the bow up with less trim and a little less stern lift. You can find one on Craigslist for around $100 quite inexpensive trial. Sell it if it doesn't work.
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Old 10-01-2019, 07:02 AM
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Really? I would have thought a 3 blade would hurt me more than help...may have to give it a shot...I def need more bow lift as the boat runs pretty "wet" at speed...if anything it will give me a cheap baseline of which way I need to go I suppose....thanks!

Any other opinions out there?
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Old 10-01-2019, 03:06 PM
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Anyone else??
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Old 10-01-2019, 05:21 PM
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How deep is the propshaft below the bottom? On a extension box?
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Old 10-01-2019, 05:26 PM
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No box and I will have to measure to get an exact measurement but I would guess with the shorty it's 5 inches or so below the bottom of the boat...the non stepped heats were pretty deep from the factory
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Old 10-01-2019, 06:06 PM
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I think you’d have too much slip with a 3 blade at just 5” below without a box. The Rev4 prop carried my boat very well, but I’ve heard they don’t lab very well. I never had good results with a bravo1. In my opinion they’re an old design that’s good for pushing a boat straight but not much lift. I think a 5 blade would creat too much stern lift at that depth. Prop testing gets old fast but it’s very hard to know what’s going to work without trying it.
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Old 10-02-2019, 06:52 AM
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It was hard to get a 100% accurate measurement as I can't drop the drive fully on the trailer...however I got it down close to level with the bottom and it was between 4 and 5 inches propshaft center below the bottom of the boat

I agree prop testing is already getting old that's why I was seeking a little advice on which direction I should head...Like I said before I do know that the stepped bottom guys almost exclusively use the hydro P-5X but I'm not sure about my non step pad bottom....I'd like to get my hands on a 24 bravo just to try it and see if my RPM's come up and how that relates to speed considering how high I have to trim it to get the speed I get...If the RPM's come up and I don't gain any speed then that will show me that I am just creating more slip with no gain correct? So then I would try something with more bite like a 5 blade maybe? I'm pretty new to this prop testing game so any advice would help...I called brett at bblades like 2 months ago and never got a call back...was thinking of trying him again today and picking his brain a little on which direction I should head as well
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Old 10-19-2019, 08:52 AM
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I think you need to get the bow up without so much positive trim. We use a box stock 29 Bravo FS on our rage walk through BR. Picked up 2.5mph over stock Bravo 1 26. We are running a 520 so I propped the boat to run 5050 rpm at 80.
Your 26 is the right prop to use. Get 5/8 of the diffuser cut off and get it labbed. That will put you around 5400rpm give or take. If you want to get to your 5700rpm range start with a 25 or 25.5 Bravo 1 FS. Then tune as needed. They are the best deal around only about $40 more then a box stock bravo 1
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Old 10-19-2019, 08:54 AM
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Bob Teague swears the Max 5 is the bomb on the heat. Only problem is its $2700 to find out.
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