I know the prop options in 2020 for the 400/1.76 was a 16x17 and 16x15, looks like there is a new option 16x13.9
Anyone running the ACME 3591 16x13.9? Sounds like an absolute stump puller.
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I know the prop options in 2020 for the 400/1.76 was a 16x17 and 16x15, looks like there is a new option 16x13.9
Anyone running the ACME 3591 16x13.9? Sounds like an absolute stump puller.
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That’s what I’m running on my SEQuote:
Originally Posted by larry_arizona
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I run the 16x15 on my 400 with 1.76 and it does fine fully loaded and tops out at 38.
The 13.9 assuming the same prop slip would only drop the top speed to 35 and would likely be significantly torquier down low.
Seems like a good option to me.
35 top speed is plenty, I will order the 16x13.9
The fastest I go is wakeboard speeds 22-23mph
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I have the 16x15, and have considered trying the 16x17. There are no issues launching, but the rpms are a little higher at surf and wakeboard speeds. Anything taller would be nuts.Quote:
Originally Posted by larry_arizona
What RPM does the 16x15 give at wake and surf speeds?Quote:
Originally Posted by Shoebox
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Full ballast surfing 11.2-11.4 I'm about 3700-3800 rpm, with lead and maybe a little water ballast at 22 is about the same. I do have the 450 though.Quote:
Originally Posted by larry_arizona
@Shoebox what's your drive ratio?
I'm 1.76 : 1 and run about 3200-3400 at surf speed on the 16x15 prop full ballast
That’s nice and low for Rpm’s
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Curious how much RPM would increase with the 16x13.9?Quote:
Originally Posted by SONIC
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Probably +8% all round if slip I the same.
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The prop calculator I use is showing about 200-250 rpm increase with the same slip.
That’s 8%. [emoji851]
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Pretty much yep :D
1.76. I also have 1k lead.Quote:
Originally Posted by SONIC
I would be happy surfing at 3600rpm with a 16x13.9
Do you have the prop slip calculator?
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https://www.rbbi.com/folders/prop/propcalc.htm
Here you go, good to play around with.
I thought lower Pitch was supposed to produce lower RPM, and lower Top Speed.
I was just up at Tahoe with 3k of people and lead and running 3800 rpm at 11.4.
I would think the 16x15 would be sufficient. I run the 16x17 now and all 100% full ballast+ 500 lbs lead distributed evenly side to side + crew of 4-5 adults and I have not experienced any lag pulling a surfer. 400 engine. I thought it would be necessary to go down to 16x15 but have not been hurting for it. I do plan to get a second prop and it'll be 16x15 but frankly, not out of necessity. Just my 2 cents.
I just cant imagine what I'm gaining by moving down to a 13"pitch. Loose speed, increased RPM. Considering how my boat handles it now, I just don't see the payoff for what I'd be giving up.
Supra no longer offers the 16x15.
Choices are
Standard 16x17
Optional 16x13.9, 16x12.5
My dealer recommends the 16x13.9, 80% take rate.
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No. It will produce a lower speed at the same rpm as before, but more torque/thrust. So if you have a top engine speed of 5000rpm, your top speed will be lower at that rpm the it was was with a higher pitched prop.Quote:
Originally Posted by DNIXD99
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The 16x13.9 sounds weird AF—must have a lot of cup to make up for the pitch. Any idea what cup is?Quote:
Originally Posted by larry_arizona
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Well that makes sense then. I guess my 2943 (10.5 pitch) was operating properly. I had more torque, but higher RPMs at the same surf speed. I see a lot of people doing the exact same thing, and expecting lower RPMs at the same surf speed. I went back to my 2419 (12 pitch). It has just enough power for my setup, and runs about 300-500 less RPMs. Ideally, I think Id want an 11.5, but Acme doesnt sell it. Thanks for the clarification. It makes sense.Quote:
Originally Posted by Stazi
Cup is .105”Quote:
Originally Posted by dakota4ce
Here is the link:
https://acmemarine.com/products/acme...-13-90-4-blade
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Seem to remember that .025 cup sort of acts like 1” of pitch, or at least can. This makes sense if my recall is on.Quote:
Originally Posted by larry_arizona
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Seems like someone designed a very specific prop..... perhaps SC custom designed this prop for the 1.76 trans? The 13.9 is a very specific pitch.Quote:
Originally Posted by dakota4ce
It appears to have replaced the 16x15 prop option.
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I did just chat with Jim at Acme two days ago and he did not mention it. Oddly enough. And I called specifically to discuss 16 X 15.Quote:
Originally Posted by larry_arizona
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To clarify, SC no longer offers the 16x15 option, at least not on the Supras.Quote:
Originally Posted by dakota4ce
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Moombas are all OJ props from the factory. Always strikes me as peculiar. The factory 15.5x16.5 may be just fine, too.Quote:
Originally Posted by larry_arizona
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I guess people were still looking for a bit more from the 16x15 so they dropped it to the 16x13.9 (agreed odd number there, they are usually in increments of .25)
I'd go that route personally, when I need a spare I'll probably grab one.
Except is has enough more cup to act like the 15” in a basic sense. It must offer an advantage for hooking up better.Quote:
Originally Posted by SONIC
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I ran my 16x15 heavy as a MF in my SL and it was plenty of grunt. 5100# of water plus 300 lead on wakeboard plane like a rocket.
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16x13.9 with heavy cup may be more efficient than a 16x15
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It's my understanding that more cup has more holding power in the water so it should hook up better with less slip out of the hole.
More cup also can increase top speed.
how the hell any of the physics work on a propeller Is over my head haha
I'm waiting on one of these to become available for the wake boat segment:
https://www.sharrowmarine.com/
Lol, for $5000 I will wait. Also would not run a Stainless steel prop on a V drive unless it had some form of engineered sheer pin.Quote:
Originally Posted by SONIC
https://uploads.tapatalk-cdn.com/202...fa2d4e0258.jpg
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I agree it's probably still years out from being affordable but the tech is very cool and apparently it really works and reduces fuel usage and plane speed considerably which would be awesome on a wake boat. They also have videos showing it essentially eliminates cavitation at the prop edges.Quote:
Originally Posted by larry_arizona
if they can CNC it from stainless they can do the same from Nibral.
They started them for tankers where a 1% increase in fuel economy is millions of dollars
I was running the 3337 (16x15 with 0.075 cup) on my 2020 SL400. We run full ballast, 500 lbs of lead (all towards the back to get the nose up to about 9.5 degrees), and a crew of 6-8 adults. Had no problems surfing 11.4 mph at 3k feet of elevation (3750 RPM +/-150 at depending on load and pitch), but fully weighted on a hot day we could not plane out. We don't wakeboard so this is not usually a problem for us. But, we took the boat up to 5k feet of elevation and it could barely hold 10.0 mph fully weighted. We came prepared and pulled the boat out to put on a 3409 prop (16x13 with 0.150 cup) and it solved all of our problems! Shockingly surf RPM is exactly the same but we have more holeshot, it gets up to speed faster, is much more responsive, and if we hit a wave it can easily temporarily rev above 4k to maintain speed (something the 3337 could not do). We can even slowly plane out fully loaded at 5k feet now. I was not expecting that out of the 400 motor - thank you Supra Launch! Fuel efficiency for surfing is also slightly improved - went from averaging 7 gph to 6.5 gph. Even though it's running the same surf RPM, the motor sounds like it's not working as hard and is slightly quieter. Top speed dropped from 37 to 34 mph so fuel efficiency while cruising at 25 mph (3800 RPM vs. 4100 RPM) has gone down but it's a small price to pay for a WAY better set-up. I highly recommend the 3409 for anyone with the 400 motor and 1.76 transmisison. I was originally planning to only use this prop when we were boating at elevation but we're leaving it on all the time now. Even at 3k feet it's a noticeable difference and much better.
Awesome feedback.
This is awesome, sounds like the 16x13.9 .105 cup will be a good choice under 2000 feetQuote:
Originally Posted by mmmkay
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