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2015 23LSV w/ 555hp: Top Speed?


cashito

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what "calcs" are you using?

Some WAG or some algorithim known and used by others?

New to site, not sure how to ask THE HULK the above question(s)!

Edited by DOOFUSisaCAT
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Proceed cautiously on going with the high pitch prop. It may not perform the way you are thinking it will.

I ran a 16 x 15.5 prop on my G23 550 and while I did save gas and reduce RPMs I missed all of the low end hole shot. I also experienced cavitation too so you'll want to take off slower than normal. Maybe I just love power but I ended up going back to the stock prop which is a 15 x 14.25 if I recall correctly.

yea i appreciate the info... its a tough decision for trial and error when you cant swap props or try em out.

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I can tell you you wouldn't want to go any bigger than a 16x16 on 1:48:1 550. It's a big prop... right at the point where Rpms are so much lower that heavy 23mph performance starts to fade some.

I didn't experience the cavitation Joe did. I have 3 props right now: 16x16, 16x15.5 and the OEM 15x14.25. I probably have 60hrs on the OJ 16x16, absolutely love it.

If I were a 24mph wake pro fanatic pushing a 7000lb boat with 5000lbs total ballast up to 24mph, I'd have a 16x14.5 on there. Rpms and gph usage goes out the window, it'd be all about performance.

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I can tell you you wouldn't want to go any bigger than a 16x16 on 1:48:1 550. It's a big prop... right at the point where Rpms are so much lower that heavy 23mph performance starts to fade some.

I didn't experience the cavitation Joe did. I have 3 props right now: 16x16, 16x15.5 and the OEM 15x14.25. I probably have 60hrs on the OJ 16x16, absolutely love it.

If I were a 24mph wake pro fanatic pushing a 7000lb boat with 5000lbs total ballast up to 24mph, I'd have a 16x14.5 on there. Rpms and gph usage goes out the window, it'd be all about performance.

ryan, do you have any idea what the equal would be in a 15" diameter? 15x17 or 15x18 or other?

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2013 23lsv around 52-54mph 52 all day long but light on gas and ppl and no wind early in the morn and me only 54 with a 1235 prop (14.5x14.25)

granted a 2014-2015 boat is significantly heavier deeper boat "above rub rail" so not sure how the weight affects top speed but the prop will surely. many discussions on here with this.

i will be getting a 15x17 prop and expect to lower surf rpms by about 300rpms and gain about 4-5mph top end with stock LSA on a 2013 LSV

if you want another 5mph then you need to do a lingenfelter pulley upgrade and a street tune, which will raise your max RPMs along with give you an extra 74hp and a whopping 79 ft lbs more torque up to 630hp / 630 ft lbs. Cost $600 and you need someone who can street tune... the power isnt really whats needed other than the RPM increase to spin the prop faster to an extent.

going slightly higher pitch on the prop will make a difference but my guess is anything after a 15x17.5 or 15x18 then it will start negatively affecting the bottom end with a stock LSA, (we have learned on here than older Malibu with a LSA and 1.25:1 tranny spun a 15x16 without issues and was about just right, so with a 1.48:1 gear box (more torque lower prop rpms) a slight increase in pitch is desired so something along the 15x17 , 15x17.5 or 15x18 range. Also we learned a MasterCraft with the big boy NA engine comes equipped with a 15x17.5 and i think with the 1.48:1 if i recall and they said it was great. i was going to order a 15x16 but feel with the 1.48:1 i should go with a 15x17... For surfing we would all love to go 16x16 but not enough haul clearance on a bu. Nyryan is throwing a 16x16 on a G23 and says its great.

if you want to add some top end go with the lingenfelter pulley upgrade! haha... i do belive you could spin a 15x18 or 15x19 easily and knock another 100-150rpms off the bottom and increase top end roughly 10-12 mph over the stock LSA with 14.5x14.25 or 5mph more than stock LSA with a 15x17...rough estimates. The pulley upgrade is nice as it gains more power at lower rpms, but also is tuned for higher rpm max as well. Once warranty is up i'm going for it baby!! even if for no other reason than bragging rights of 630hp... you need some device to connect to a laptop and someone who knows how to tune the O2/fuel mixture etc.. I found someone =) cant wait, but will be another year haha. and will probably be old news since everyone could care less since the LSA is out of commission for new boats moving into the future.

rough calcs you would need to go with a 15x17, 15x17.5 or 15x18 but i fell you will be close with 17" pitch

what are your RPM's then its easier to calculate, say you reach 5400rpms

15x15.75 prop should in theory give you 54mph 'thrust" granted you cant hit 54mph because some of that force is downward nor horizontal so i'd say your about right at 46-47mph

15x17 prop should in theory give you 58-59mph thrust, so roughly 5mph thrust more than what you have but how much of that equates to fwd motion and prop/shaft angle i dont know, but i think you would pick up at a minimum half the difference and assuming rmps remain same with both props you should get 2-3 mph more is my guess

15x18 prop should give you about 62mph thrust. so perhaps another 2-3 mph fwd speed more yet which should get a solid 50-53mph is my guss if rpms can hold the same...big question there.

it would be so fun to try a 15x17 vs 15x18 but to be safe i'll be ordering a 15x17 but my guess is she'll handle the 15x18 i just wonder where the line gets crossed, i mean the MC has a 15x17.5 so it makes me wonder honestly if a 15x18 might be the ticket ahhhh decisions and $$$$$ and the unknown...

ahh decisions decisions 15x17, 15x17.5 , 15x 17.75, 15x18

now i'm wondering more and more! ahhh

i wish we could figure the calc based on nyryans 16x16. physics tells me that a slight decrease in diameter should result in much bigger pitch to equal same forces. the larger the diameter the bigger resistance leverage point and gets exponentially harder for the engine to turn that prop as the water has a bigger leverage point from the center of the shaft/prop.

i wish i could find some math of the force difference between diameter and pitch. if the 16x16 is in theory perfect according to the master than my guess is we may need to consider the 15x17.75 or 15x18. were stuck with 15" diameter so a few pitches up should be at a minimum the same or still less than a 16x16..

Hulk,

I don't see how you can hit 52 or 54 mph with your current prop. Yes, to max out your speed, steeper props move faster, but you're assuming you can still get the engine to wind all the way up. Either way, here's how I can prove you're not even seeing the performance you claim you are (ie, your speedo is off):

Assuming you hit even 5500 RPM (which you're likely not) and assuming your reduction is 1.46 (you cited 1.48 but elsewhere on here people say 1.48 is in the PCM in axis, 1.46 on late model indmars, but either way, 1.46 is in "your" favor for this exercise), the shaft is spinning 3767 revolutions per minute. With NO SLIPPAGE WHATSOEVER and PERFECT ENERGY TRANSFER ASSUMING YOUR PROP WAS RUNNING LEVEL (which its not), each revolution of a 14.25" prop moves the boat 1.1875 feet. We'll round to 1.19 giving you now the benefit of the doubt on RPM, no slippage, and rounding numbers in your favor. If you multiply 3767 by 1.19 you get 4482, which is the distance in feet you would travel in one minute. That's 50.1 mph. Again, that's assuming you're hitting 5500 and you have no slippage and perfect lateral force transfer, of which you have neither. I think your speedo is off or you're reading in RPMS. Do you see a mathematical flaw in the above?

The only thing not addressed is cup but cup can't mathematically overcome no slippage and perfect pitch.

Edited by 85 Barefoot
  • Like 2
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Joe,

I have 15x14.25 now, i would welcome less hole shot. I have to warn the driver not to rip my arms out of socket. For sure will be a balancing act. I have no interest in gaining top end, as i typically cruise 25 or so. I surf 95% so as long as i can get to ~11.3 with the boat slammed, i will be a happy guy.

My goal is to get through a full day on one tank of gas. That is the root of my issues. Do you spend the extra $100 for 25 gallons of marina gas, or do you go home? Plus the wasted 45 minutes going to the marina.

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Hulk,

I don't see how you can hit 52 or 54 mph with your current prop. Yes, to max out your speed, steeper props move faster, but you're assuming you can still get the engine to wind all the way up. Either way, here's how I can prove you're not even seeing the performance you claim you are (ie, your speedo is off):

Assuming you hit even 5500 RPM (which you're likely not) and assuming your reduction is 1.46 (you cited 1.48 but elsewhere on here people say 1.48 is in the PCM in axis, 1.46 on late model indmars, but either way, 1.46 is in "your" favor for this exercise), the shaft is spinning 3767 revolutions per minute. With NO SLIPPAGE WHATSOEVER and PERFECT ENERGY TRANSFER ASSUMING YOUR PROP WAS RUNNING LEVEL (which its not), each revolution of a 14.25" prop moves the boat 1.1875 feet. We'll round to 1.19 giving you now the benefit of the doubt on RPM, no slippage, and rounding numbers in your favor. If you multiply 3767 by 1.19 you get 4482, which is the distance in feet you would travel in one minute. That's 50.1 mph. Again, that's assuming you're hitting 5500 and you have no slippage and perfect lateral force transfer, of which you have neither. I think your speedo is off or you're reading in RPMS. Do you see a mathematical flaw in the above?

The only thing not addressed is cup but cup can't mathematically overcome no slippage and perfect pitch.

85, that is beautiful!

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Hulk,

I don't see how you can hit 52 or 54 mph with your current prop. Yes, to max out your speed, steeper props move faster, but you're assuming you can still get the engine to wind all the way up. Either way, here's how I can prove you're not even seeing the performance you claim you are (ie, your speedo is off):

Assuming you hit even 5500 RPM (which you're likely not) and assuming your reduction is 1.46 (you cited 1.48 but elsewhere on here people say 1.48 is in the PCM in axis, 1.46 on late model indmars, but either way, 1.46 is in "your" favor for this exercise), the shaft is spinning 3767 revolutions per minute. With NO SLIPPAGE WHATSOEVER and PERFECT ENERGY TRANSFER ASSUMING YOUR PROP WAS RUNNING LEVEL (which its not), each revolution of a 14.25" prop moves the boat 1.1875 feet. We'll round to 1.19 giving you now the benefit of the doubt on RPM, no slippage, and rounding numbers in your favor. If you multiply 3767 by 1.19 you get 4482, which is the distance in feet you would travel in one minute. That's 50.1 mph. Again, that's assuming you're hitting 5500 and you have no slippage and perfect lateral force transfer, of which you have neither. I think your speedo is off or you're reading in RPMS. Do you see a mathematical flaw in the above?

The only thing not addressed is cup but cup can't mathematically overcome no slippage and perfect pitch.

I misatake my tach for my speedo A LOT when doing quick glance checks.

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Hulk,

I don't see how you can hit 52 or 54 mph with your current prop. Yes, to max out your speed, steeper props move faster, but you're assuming you can still get the engine to wind all the way up. Either way, here's how I can prove you're not even seeing the performance you claim you are (ie, your speedo is off):

Assuming you hit even 5500 RPM (which you're likely not) and assuming your reduction is 1.46 (you cited 1.48 but elsewhere on here people say 1.48 is in the PCM in axis, 1.46 on late model indmars, but either way, 1.46 is in "your" favor for this exercise), the shaft is spinning 3767 revolutions per minute. With NO SLIPPAGE WHATSOEVER and PERFECT ENERGY TRANSFER ASSUMING YOUR PROP WAS RUNNING LEVEL (which its not), each revolution of a 14.25" prop moves the boat 1.1875 feet. We'll round to 1.19 giving you now the benefit of the doubt on RPM, no slippage, and rounding numbers in your favor. If you multiply 3767 by 1.19 you get 4482, which is the distance in feet you would travel in one minute. That's 50.1 mph. Again, that's assuming you're hitting 5500 and you have no slippage and perfect lateral force transfer, of which you have neither. I think your speedo is off or you're reading in RPMS. Do you see a mathematical flaw in the above?

The only thing not addressed is cup but cup can't mathematically overcome no slippage and perfect pitch.

Don't forget it's a Malibu, the only boat that takes the raptor from 400 to 410 and raptor 440 to 450 by just putting in a Malibu, so to see the speedo say 54 when a prop calculator with 10% slip says that 46 is the top speed is reasonable :)

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I don't disagree the gauge is off a few mph but it's all I have to go buy when I GPS on phone I have weak signal and it's close check the Calc I had on the other thread for theoretical "thrust speeds"

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Hulk,

I don't see how you can hit 52 or 54 mph with your current prop. Yes, to max out your speed, steeper props move faster, but you're assuming you can still get the engine to wind all the way up. Either way, here's how I can prove you're not even seeing the performance you claim you are (ie, your speedo is off):

Assuming you hit even 5500 RPM (which you're likely not) and assuming your reduction is 1.46 (you cited 1.48 but elsewhere on here people say 1.48 is in the PCM in axis, 1.46 on late model indmars, but either way, 1.46 is in "your" favor for this exercise), the shaft is spinning 3767 revolutions per minute. With NO SLIPPAGE WHATSOEVER and PERFECT ENERGY TRANSFER ASSUMING YOUR PROP WAS RUNNING LEVEL (which its not), each revolution of a 14.25" prop moves the boat 1.1875 feet. We'll round to 1.19 giving you now the benefit of the doubt on RPM, no slippage, and rounding numbers in your favor. If you multiply 3767 by 1.19 you get 4482, which is the distance in feet you would travel in one minute. That's 50.1 mph. Again, that's assuming you're hitting 5500 and you have no slippage and perfect lateral force transfer, of which you have neither. I think your speedo is off or you're reading in RPMS. Do you see a mathematical flaw in the above?

The only thing not addressed is cup but cup can't mathematically overcome no slippage and perfect pitch.

I agree, although I have a a22 with ls3, I still have the 1235 prop and at WOT, i am lucky if I hit 40mph. I think I may have seen 42 once. Unless you have the stock prop or something with more pitch, I doubt you can even get into the 50's and still have enough prop to wake surf weighted.

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1/1.48 x engine rpm X prop inch pitch /12 in = ft/min convert to mph = thrust mph .....only talking thrust mph

Have not been to lake in over 1 month was looking for feedback if anyone knows is a 2013 has a 1.48 or something else? With the LSA maybe is a 1.25? Mabel I'll get to lake this wkd to check what it really is or perhaps it's a 1.46?

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Joe,

I have 15x14.25 now, i would welcome less hole shot. I have to warn the driver not to rip my arms out of socket. For sure will be a balancing act. I have no interest in gaining top end, as i typically cruise 25 or so. I surf 95% so as long as i can get to ~11.3 with the boat slammed, i will be a happy guy.

My goal is to get through a full day on one tank of gas. That is the root of my issues. Do you spend the extra $100 for 25 gallons of marina gas, or do you go home? Plus the wasted 45 minutes going to the marina.

Dark

I'd say a higher pitch prop will definitely get you more time on the water while making that full tank of gas last longer.

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If i could get down to sub 8 GPH surfing i will be a very happy guy. 8 would get me 7.5 hours of water time. We kill engine between riders, so idle very little. Although our groups are frequently 7~8 i have been trying to limit my group to <5 riders so we get ~4 sets in each. Usually 7~8 hours run time is all we can take. But that is a FULL day on the water. 11 hours plus.

I am also done with full day trips for the year. Soccer season is now forcing weekday trips, and occasional Sunday afternoon trips. The good news is its FOOTBALL season, and people stay home too watch the game leaving good water for me. My next full day trip will likely not be until Christmas/New years.

  • Like 2
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8 GPH is attainable with the LSA. Nyryan and I have seen and experienced it this year. I look forward to seeing what prop you get and sharing the the results.

Edited by JoeA
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