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Whirlwind SW to Sensenich JX????

L

Lighten

Member
Iam looking for input on what rpms your turning at what pitch on Whirlwind SW blades. I feel like these are hard to turn blades, or i dont have the set right or a different prop would wake the boat up. Rite now i have mine pitch at 25* on the A mark at 4850 rpms on the trailer , i feel like it runs the best here at 3600 cruise and moves on dry at about 3900. I have had it pitched from 4900 up to 5250 rpms, testing on dry only, and it felt like it didnt have as much push, kinda like a loose converter that is slipping. Prop diameter is 84” and can not go any bigger. Thinking maybe i need to try the JX blade in same diameter? any input from your experiences would greatly be appreciated before i spend the money on a new prop. Thanks

16x8 3/4 deck, 540 bbc 2.67 CH4
 
Lighten said:
Iam looking for input on what rpms your turning at what pitch on Whirlwind SW blades. I feel like these are hard to turn blades, or i dont have the set right or a different prop would wake the boat up. Rite now i have mine pitch at 25* on the A mark at 4850 rpms on the trailer , i feel like it runs the best here at 3600 cruise and moves on dry at about 3900. I have had it pitched from 4900 up to 5250 rpms, testing on dry only, and it felt like it didnt have as much push, kinda like a loose converter that is slipping. Prop diameter is 84” and can not go any bigger. Thinking maybe i need to try the JX blade in same diameter? any input from your experiences would greatly be appreciated before i spend the money on a new prop. Thanks

16x8 3/4 deck, 540 bbc 2.67 CH4
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Is it a 3 blade 84” SW or a 4 blade? If it’s a 3 blade I’d suggest adding a blade and getting that pitch around 20° on 4 blades. If you’re running a 4 blade already I’d get a 5 blade SW and follow suit mentioned above. With that 2.67 ratio you need blades and diameter to get the push since you’re turning it only 1800rpm. Not really a good ratio for a bbc only turning 5000~. I’d have recommended a 2.3 or 2.52 max
 
I have the same blade on a 540BB (now a 555BB) with a 2.55 gearbox and love it. The best setup I've found with those blades is to stagger the pitch by 2°. So basically it's like having 2 2blades. So for instance set 2 blades that are in line with each other at 20° and the other 2 at 22°. I've tried every way possible with the blades and this way is by far the best and actually the smoothest blade I've run. The other thing I can tell you from selling and setting up many Whirlwind Props is even though there marks go past 20 on the prop once you get past that you really need more prop because the performance just isn't the same much past that 20 mark.
 
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I am new to aircraft engines I have a 0470 continental on a 13 laser hull I am wanting in to run the hill it has a 72 in whirlwind and it’s set at b 20 what can I set it to without going over 2900 rpm’s I am still learning so any advice would help
 
Coastslider said:
what rpm max HP/TQ ?
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I dont know that. I built the engine myself and never had it dynoed. It has 10.6-1 compression if i remember correctly and running Holley Sniper Xflow fuel injection. Iam guessing 650hp around there. Has a fairly small cam also
 
Gladesman06 said:
I have the same blade on a 540BB (now a 555BB) with a 2.55 gearbox and love it. The best setup I've found with those blades is to stagger the pitch by 2°. So basically it's like having 2 2blades. So for instance set 2 blades that are in line with each other at 20° and the other 2 at 22°. I've tried every way possible with the blades and this way is by far the best and actually the smoothest blade I've run. The other thing I can tell you from selling and setting up many Whirlwind Props is even though there marks go past 20 on the prop once you get past that you really need more prop because the performance just isn't the same much past that 20 mark.
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So adding another blade and staying same diameter, maybe get pitch down to 15-20 ?
 
If you over pitch the blades too much your just beating the air into submission. I am in a similar situation with adding over 100hp to current setup and I am already pitched pretty aggressive.

Call the manufacturer and advise them and they will probably want you to send the current blades so they can make sure to balance all 5 to prevent unwanted vibrations
 
Old post guys but we can wake it up.

There is just something magical about the 2.55 ratio on a Big Block Chevy. That said you would think a 2.68 pairing with a 540 would push better.

Seems like his pitch choice what we call “choking it back” has pulled the engine down into its peak torque range for cruise. You would think that it should have more in the higher rpm however. Maybe a mismatch of a component. 5,600 in a built 540 should be in most builds very attainable and where the power is. That said choking it can improve the quality of the ride but you to sacrifice that very top of the scale performance.

We run the Super Wide Sensenich blades and they perform very well choked with pitch.

I have run a set of JX carbon race blades and found them to spin up faster than the S blades and “hit” or have more snap. For a big heavy boat that spool and snap can help it to break ground. The JX still kept ride quality the same but let engine get into its power curve easier.
 
SWAMPHUNTER45 said:
Old post guys but we can wake it up.

There is just something magical about the 2.55 ratio on a Big Block Chevy. That said you would think a 2.68 pairing with a 540 would push better.

Seems like his pitch choice what we call “choking it back” has pulled the engine down into its peak torque range for cruise. You would think that it should have more in the higher rpm however. Maybe a mismatch of a component. 5,600 in a built 540 should be in most builds very attainable and where the power is. That said choking it can improve the quality of the ride but you to sacrifice that very top of the scale performance.

We run the Super Wide Sensenich blades and they perform very well choked with pitch.

I have run a set of JX carbon race blades and found them to spin up faster than the S blades and “hit” or have more snap. For a big heavy boat that spool and snap can help it to break ground. The JX still kept ride quality the same but let engine get into its power curve easier.
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Interesting what you say about the JX race prop was wondering also how they would do on a big block
 
Lighten said:
Iam looking for input on what rpms your turning at what pitch on Whirlwind SW blades. I feel like these are hard to turn blades, or i dont have the set right or a different prop would wake the boat up. Rite now i have mine pitch at 25* on the A mark at 4850 rpms on the trailer , i feel like it runs the best here at 3600 cruise and moves on dry at about 3900. I have had it pitched from 4900 up to 5250 rpms, testing on dry only, and it felt like it didnt have as much push, kinda like a loose converter that is slipping.
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Lighten said:
Its a 4 blade SW 84”. Had a 2.3 previously and sold it, the boat moves 10x better with the 2.67 box
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I have no experience with this prop or engine, but here is my read. The 2.55 box is probably the right move, but it would be cheaper to add a 5th blade to what you have. Regardless, everyone has told you that you are over pitched at 25 deg. The prop is losing steam at the high end, not the engine.

What RPM are you looking to turn the engine to at WOT? If you were to add 1 blade to what you have you would be able to decrease pitch in all blades, putting them more in the range of best efficiency at the high end

Lighten said:
Prop diameter is 84” and can not go any bigger. Thinking maybe i need to try the JX blade in same diameter? any input from your experiences would greatly be appreciated before i spend the money on a new prop. Thanks
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The original post stated 84" max, is that a hub limit or did you find some more cage clearance? The JX blades like RPM. If you have chosen those blades, you have chosen to turn that BBC towards 5,500 RPM. Make sure the head package and cam agree. Otherwise, you are heading in the wrong direction.

Lighten said:
I dont know that. I built the engine myself and never had it dynoed. It has 10.6-1 compression if i remember correctly and running Holley Sniper Xflow fuel injection. Iam guessing 650hp around there. Has a fairly small cam also
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Reads like a engine that makes plenty of power but runs out around 5K RPM. The 2.68 is too much gear for anything that doesn't run out in the high 5,000's. The best move would be a 2.55 ratio. A 5th (or even 6th) SW blade would be a second choice.

This would be my last choice.

Lighten said:
Iam gonna try a 4 blade JX at 86" and see what happens. Will update when i get them on
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I have a 4 blade 83" JX and as stated above it wants lots of RPM'S to do much. I'm looking to change to either the R blades or a 3 blade SW. My set up is 486hp / 618tq @ 5200.
 
Got the blades on, 4 jx's at 86" pitched at 22 degrees engine at 5000 on dry ground, may play with rpms after i put it in the water. It does have more push on dry than the WW SW blades had but ill have to see what it does it on the water to see if it was worth it.
 
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