All That Glitters Is Not Gold: Solas Impellers

[swatski]

I have never been a huge fan of Solas in Yamaha JBs although I used to run SS 4-blade Solas o/b props all the time and loved them. That mirror SS finish is very enticing, but I found the impellers consistently under-performing when tested in various pump setups. Most of that testing was in my SX190, a great testing platform for Yamaha jet boat mods.

The Solas Concord may be slightly faster than the OEM Yamaha impellers, and also Skat Swirl, but at least in my hands seem more prone to cavitation on hole shot (when pitched to a similar max RPM). The lowly-looking OEM Yamaha impeller has the longest blades and tends to outperform the aftermarkets, overall. Funny thing is, those OEM imepellers can actually be brought up to the same luster/polish as the Solas, but there are no known performance benefits associated with mirror finish. Rather, the race finish offered by professional impelelr rebuilders such as Impros is "groovy", not shiny. But anyhow.

Unfortunately, these Solas also seem to be the only Yamaha jet boat impellers that suffer catastrophic failures, unlike the OEM or Skat. It is rare to have them fall apart but when it happens - it's UGLY. Just ask @dan144k... LOL.

Previously, it was thought that only a one large batch of those impellers has been affected. Well, maybe not so. It seems these issues may neither be isolated, nor resolved...

http://www.greenhulk.net/forums/showthread.php?t=267407

13/18 is in the range of impeller pitches that would be used in a 1.8l HO.

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[Speedling]

I guess if nothing else it would be good to at least inspect mine from time to time huh? I wonder what it might show before failure? Any cracks or wear?

 

[swatski]

I guess if nothing else it would be good to at least inspect mine from time to time huh? I wonder what it might show before failure? Any cracks or wear?

I think you should be fine, if I remember correctly you are running Dynaflys, rigth? These are all Concords that are exploding, from what I understand.
The most recent is kind of worrisome - basically all you can see is a hair line, but gave some vibrations the guy could feel. I doubt one would feel it in a twin boat.

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[J-RAD]

Great write-up @swatski. Great information for fist time JB owners as impellers are probably the first mods people think of for their boats without realizing the potential issues associated with the aftermarket products. Nor do they understand just how efficient the OEM impellers are. Granted there are applications where running as alternative pitched impeller may be the solution (example: extremes in elevation).
Information in this forum has convinced me that I'm not likely to see any worthwhile gains from changing. Although rumor has it the dealer here sells their boats equip with impellers pitched for higher elevation... I've never followed up on this and I'm not sure how common a thing it is among dealers. I'm near certain they're OEM, so I don't know if its a factory option...?

Anyway, I think what you've been doing recently with the Lucky 13 cones, intakes and tunes have been more effective all around performance enhancements...

I for one, certainly appreciate all of the trial research and feedback youu have graced us with here. Takes a lot of the guess work out of things for the rest of us followers. Thanks!

 

[swatski]

@J-RAD These are good points. Solas might be the ticket for elevation performance, as with their shorter blades they tend to spin faster relative to their pitch. Or at least that's the theory. Of course when you compare different impeller models, same pitch number will mean different performance! (and it gets really tricky). I think the best way to compare different impellers is to pitch them to get the same max RPM, regardless of what the actual pitch numbers are.*** In that context, the Solas tend to be the "fastest" as far as the top end, but the OEM are the "quickest" - as far as getting there. At least in general terms.****

If anyone does elevation well, it would be Impros. From what I have heard they tend to recommend Solas Concord in those applications, and I think I might actually go with that, basically taking calculated risk for performance sake. Unlike OEM impellers which can be adjusted at home (small changes to the trailing edge), bending Solas is best left to professionals and may require iterative sendouts/pitch adjustments. One thing I would insist upon (and pay extra if extra welding required) is bringing the OD back to specs as that has a big effect on cavitation prevention.

The Solas Concord and Dynafly are very similar looking, with the major difference being in the root construction. Both have relatively short blades, as compared to the new OEM (in 240s), but both are very similar to the old OEM (in 230s).

For comparison, here is a 230-style OEM (left) and a Solas Dynafly (right)
(pic courtesy of @DCB-270)


And here is a Skat Swirl (left), a Solas Concord (center - repitched, w/regular finish), and a new-style OEM (right - w/factory finish)


And here are some groovy new style OEMs (these were done by Skat's Glenn Perry - note the shine!)




*** Albeit that logic gets fuzzy with our impellers, too, as the pitch in our Yamaha boats is progressive. So, for example - I have had some impellers pitched very steep (with less differential in terms of the leading/trailing edge split) - and the results are vastly different from what you would get w/OEM split. It gets crazy.

**** Another issue which is kind of funny is - most new impellers will outperform (beat up) old ones, LOL. Regardless of the model.


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[J-RAD]

*** Albeit that logic gets fuzzy with our impellers, too, as the pitch in our Yamaha boats is progressive. So, for example - I have had some impellers pitched very steep (with less differential in terms of the leading/trailing edge split) - and the results are vastly different from what you would get w/OEM split. It gets crazy.

**** Another issue which is kind of funny is - most new impellers will outperform (beat up) old ones, LOL. Regardless of the model.
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Yeah, it's all of the "fuzzy" logic that turns me off from trying... there are just so many variables to it that I don't know that there is a silver bullet solution to answer all my desires... especially when I'm pretty content overall to begin with. I wouldn't mind a higher top speed, but what else will I be sacrificing? How much money and effort is it worth trying to pitch and repitch for minimal gains? (Not to mock your efforts in any way. Again it's knowledge gained from the efforts of guys like you having tested these things that lead me to these conclusions). But despite all you've tried on your 190 and now your 240, (if I'm not mistaken) here you are more content with running the OEM screws.

I trust that reputable companies, like Impros, know their craft and could probably swear to me up and down that they've got the solution for everything... but I don't know that I've ever read someone's review on here saying they've found a magical impeller that outperforms anything else... so for now, I'll just stick with what I've got and work on maximizing its efficiency in other aspects.

 

[tdonoughue]

I will add my thanks, as well.

Never really seriously considered changing my impellers. The ones I have work fine for me, have not given me any trouble, etc. But your write-ups and thoughtfulness in how you approach all of the changes you have made and experiments you have done has taught me loads about my boat. I admit I have never even pulled an impeller. With your write-ups and photos, I would not hesitate a moment to do so.

Then to learn that I already have impellers that are very close to the best that someone like you can find--that is pure gold to me.

So, thank you, @swatski .

 

[dan144k]

I had a local jetski speed shop tell me he suspects there by counterfeit Solar impellers available. His reason was it costs him $300 to buy one. How are people online able to sell them at $200.

Makes logical sense, kinda