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Gerk
04-21-2015, 02:00 PM
So I am looking at the Volvo Drive and water jet sheet of all of the drives and I am not seeing this lower unit on there.
It has the cone, but I really don't think it is a speedmaster.

I am not seeing an illustration of this lower end.

Thanks

82026

Morgan's Cloud
04-21-2015, 03:38 PM
It's a 280 that someone's put an aftermarket cone kit on by the look of it .

mattyboy
04-21-2015, 04:45 PM
+1 280 or 90 lower with a hydromotive nosecone added

Gerk
04-21-2015, 05:45 PM
Is that a bad thing or a good thing?
How does one even go about adding a cone?

I bought another Donzi 18 and it came with a regular 280 setup and this lower end.

I had never seen one like that.

smidgen too
04-21-2015, 07:31 PM
I bought this set of Volvo's for one my boat projects, the nose cones look cool but the performance gains my not be much.

mattyboy
04-21-2015, 08:10 PM
agree with what Smidgen said I had one and got about a mph or two but mine covered the water pick up . they need to be installed dead on balls perfect or they can cause problems. If there is any play or slop in the steering the nose cone is going to magnify it.
if your plans are for flat out speed and want 70 plus as your mph mark go to a modern power plant if the original performance envelope of mid 50s to low 60s and reliability go for the Volvo AQ.

they stopped making the nose cones so if you want one you will need to find one on the secondary market

boatnut
04-22-2015, 11:44 AM
In the early 70's I rode in an 18 at the Donzi factory and it had a sbc and a Volvo speedmaster lower unit. I guess this was just prior to the TRS drive taking Volvo out of the equation for performance. It was fast (I think close to 80) and was going to be shipped to Italy. Assuming one had or could get a speedmaster. Are there any downsides (handling etc.)? Are props available? Are there different gear ratios? I need not ask about parts availability :).

Morgan's Cloud
04-22-2015, 12:28 PM
In the early 70's I rode in an 18 at the Donzi factory and it had a sbc and a Volvo speedmaster lower unit. I guess this was just prior to the TRS drive taking Volvo out of the equation for performance. It was fast (I think close to 80) and was going to be shipped to Italy. Assuming one had or could get a speedmaster. Are there any downsides (handling etc.)? Are props available? Are there different gear ratios? I need not ask about parts availability :).


Don't know about handling down sides , and we all know about parts availability , but I think I've read from a few people who have run them that the lowers have a penchant for blowing up .

mattyboy
04-22-2015, 12:35 PM
The volvo E Drive shorty speedmaster. They ran merc racing props Mazco also made props but a different spline than a Standard AQ .They had a very slim profile which means the gears were slim as well making them weak, parts are almost non existent, cases can be found but expensive, the gears shafts and other parts good luck. We had a club member who was an engineer tool his own gears he made a couple sets for his use he thought he would need them down the road. It was a good 7-10 mph pick up on a Volvo classic and usually handled better than the standard AQ lower

Ralph Savarese
04-25-2015, 08:29 PM
Hydraulic steering on mine ans a Solas 23 5200 rpm I am seeing the edge of 70 with my aq280 no cone
Ralph

mattyboy
04-25-2015, 08:35 PM
you'd be mid 70s with an edrive

mattyboy
04-26-2015, 08:55 AM
I am trying to find the video of Brian's x18 with the edrive and stout SBC, last I remember he was still tuning but he was running high's 70s

boatnut
05-02-2015, 11:34 AM
Hydraulic steering on mine ans a Solas 23 5200 rpm I am seeing the edge of 70 with my aq280 no cone
Ralph
I have lots of experience using 250/270/280 stock drives including racing offshore production in the early 70's. With the props we had available (Volvo, Michigan, OJ/Johnson, etc) the volvo lower units seemed to work well as governor and pretty much limited the speed to the range between 55 and 60 -- seldom 60. We were running two CC marined Z28 sbc's that produced a solid 300 hp each with a 24' Magnum hull and 57 was about all we could get (salt water). Fortunately our competition had the same limitation (until the TRS surfaced) so we won lots of races. The E lower units were not legal in production but they would add about 10+mph with the same engines in modified classes. Similar experience with single engine Donzi boats. These props ran out of water in that speed range. So obviously the solas props and work done by Grizzley resulted in significant gains. We will soon be putting our 18 back together with a 250 stock lower unit. Are any of these Solas-type props still available, new, used?? Thanks, Ed

mattyboy
05-02-2015, 01:45 PM
I have lots of experience using 250/270/280 stock drives including racing offshore production in the early 70's. With the props we had available (Volvo, Michigan, OJ/Johnson, etc) the volvo lower units seemed to work well as governor and pretty much limited the speed to the range between 55 and 60 -- seldom 60. We were running two CC marined Z28 sbc's that produced a solid 300 hp each with a 24' Magnum hull and 57 was about all we could get (salt water). Fortunately our competition had the same limitation (until the TRS surfaced) so we won lots of races. The E lower units were not legal in production but they would add about 10+mph with the same engines in modified classes. Similar experience with single engine Donzi boats. These props ran out of water in that speed range. So obviously the solas props and work done by Grizzley resulted in significant gains. We will soon be putting our 18 back together with a 250 stock lower unit. Are any of these Solas-type props still available, new, used?? Thanks, Ed


yes on ebay or from any solas dealer you are looking for the Titan for the VP AQ they make the Titan for other drives and motors. Looks like the prices have come down were up around 400

http://www.getaprop.com/content-product_info/product_id-7621/solas_titan_3_long_hub_propeller_volvo.html

rule of thumb given to me by Big Grizz that was for the props he designed which acted 1-2 inches bigger in pitch now they are more like 1 inch in pitch bigger as mass production props from Solas.

less than 300 HP = 19
300-350 ish =21
350+ =23

my 16 ran a solid 60 with 310 hp day in day out with a 21 solas at 4900-5000 rpm on 1.6 gears
the Hornet runs right to 50 with stock sbf hp with a 19 solas at 4800 on 1.6 gears

Gerk
05-04-2015, 05:00 PM
So one of these Solas props will give significant gains on an unmodified 270 or 280?

I could be into that.

My buddys '77 with sbc 350 and stock 270 runs a cupped 14x19 and it is good for Tahoe altitude. Could be a 14x21 but not 100%
He would like more speed if possible.

If it is good, I will buy one too

mattyboy
05-04-2015, 08:09 PM
So one of these Solas props will give significant gains on an unmodified 270 or 280?

I could be into that.

My buddys '77 with sbc 350 and stock 270 runs a cupped 14x19 and it is good for Tahoe altitude. Could be a 14x21 but not 100%
He would like more speed if possible.

If it is good, I will buy one too

If he is turning a 14x19 now a Solas 19 will drop his rpms at least 200 rpms and will probably be slower probably a lot slower in the thin air

Need the exact numbers rpm drive ratio pitch and a speed GPS if possible than it can be evaluated

Gerk
05-04-2015, 09:50 PM
Thanks Matt, You are always a big help.

He is turning a 14x21 cupped. Max RPMs at full throttle is 5100 and max speed seen on GPS is 53 but most of the time 50 MPH.

I hope I am answering that question right. He would love to get a few more MPH. He does not want to change the drive yet as the boat runs.

I am running almost the same setup except ford, so this prop is for me too.

mattyboy
05-05-2015, 07:50 AM
altitude aside I am much closer to the sea and don't know thin air.

with the increased diameter and grip of the solas spinning a 19 would keep his rpms near 5000 maybe a little less and in the area of 54-55 mph

with a 21 solas his rpms are going to be down to around 4700-4800 if he can spin it to 4800 he is at 55-56 I think he will be more at 4700 and back at 54-55 mph

remember this is not an exact science these numbers may be a bit high but the solas will give you good performance and handling and should get the boat moving near the speed he has now but the motor and drive will be happy with the lower rpms. If his prop is over marked and it is a 19 that was repitched and a flexed back towards it's original pitch he is going to lose more rpms than I estimated

mattyboy
05-05-2015, 09:16 AM
forgot to mention running the numbers you've given us on his current prop he is at approx 16% slip which is not uncommon in a volvo AQ prop
the solas will be down at around 7-8% slip.

Again you have to check your motor's ego at the door I was running a 25 pitch and 26 pitch modified merc props near 5000 rpm they were high in slip I could not turn a 23 solas I went down to a 21 solas to get in the 4900-5000 rpm

the props are around 300 dollars I would say start with a 19 you can split it between you and your friend test it and see where you are it is always good to have a spare prop if needed

Gerk
05-05-2015, 10:50 AM
Excellent. I think we will give it a try.
Does anyone know anything about cupping? Will this still be OK as his runs much better with the cupping on his Volvo prop.

Also, if hes running a 21, a 19 you think is best?

Thanks, just don't want to buy the wrong one and spend extra money

Gerk
05-05-2015, 11:06 AM
Also, on the website, it says the Solas Titan is for the 280/290.

Will this not work on a 270?

mattyboy
05-05-2015, 11:20 AM
the rules of thumb for every inch of pitch or diameter it is 200 rpms up in pitch or diameter down in rpm and vice versa

the solas is almost an inch wider and the blade area is much larger and has cupping . so a solas acts larger than the posted number so a 19 acts more like a 20-21 and a 21 acts like a 22-23. the prop he is running now is at 15-16% slip which means it is inefficient the solas is twice as efficient at 7-8% which means it is hooked to the water.

The point being there is more likely chance that the 21 will be harder to turn and drop his rpm too low and be disappointed in performance. In thicker air with 310 hp I could barely get a 21 solas to 4900-5000 rpm on 1.6 gears.

props are never cut and dry what works for one setup might not work as well on another setup, my 16 ran great with a solas 21 Jay's 16 did not with similar power but slightly different drive Jay's boat liked the 19 more.

knowing the solas and not knowing exactly the type, make and design of his existing prop, with stock power at high altitude I would try the 19 first.
Again if he can spin the solas 19 to 5100 ( which I don't think he will be able to) he is at 55 mph

selling spare volvo props has never been an issue make a post in wanted someone may have a 19 that they are willing to part with and a decent price. You may need to buy and test

I have about 240 ish HP coming out of a SBF i can get a 19 to about 4800 what is a stock 350 SBC 260 ish hp ?

mattyboy
05-05-2015, 11:33 AM
Also, on the website, it says the Solas Titan is for the 280/290.

Will this not work on a 270?

yes I have seen or run a solas on a 200-250-270-280 and 290

you may need (as does every AQ owner) an assortment of thrust washers and may need to tap and drill the shaft for a backing bolt but with off the shelf parts I ran many short and long hub props on my 250.

I wrote a test thread for Rootsy and Big Grizzly over on .org years back not sure if the thread is still there but it listed how to get it to fit on a 250-270 and what mods I made on my 250 ( which is the same lower as a 270) think I used an OB torque tab which in hindsight I didn't really need

if he has the exhaust torque tab combo the solas won't fit the exhaust port tab needs to go.

Gerk
05-05-2015, 01:19 PM
Sorry for asking so many questions.

Is the titan the way to go?
There is the Amita, the saturn, etc....

I am only looking at the titan as that is what is linked.

Props can be very confusing to get the right one and seems extremely easy to get the wrong one.

mattyboy
05-05-2015, 03:50 PM
No need to apologize for questions
Yes you are looking for the Titan not the others the Titan is well worth the money. It was developed for rhe aq drive the others are sx drives with the old hub I tried a ton of props I had an inventory of about 10 props at one time alum bronze SS choppers cleavers round ears stop switching when I got a Volvo ultra when I got my Solas Titan I sold everything including the ultra it is the best all around prop I ever used on a Volvo no blowout no ventilation no handling quirks

Everyone that has tried one has thought they were a good prop

Gerk
05-05-2015, 09:58 PM
Ok so I am ready to purchase one of these Titans.

Now the question is RH or LH.

I will be running Right hand drive with 351 and my buddy has the 350 and Left hand drive.

I think Volvo can run either one, but I am not sure how that works.

Much appreciated on the help

mattyboy
05-05-2015, 10:04 PM
what ever side your helm( steering wheel) is on left side LH right side RH

visit our club site( click on the club logo in my signature at the bottom of this post) look at the resources page under the restoration radio bar we have some Volvo owners manuals there will help


changing rotation is on page 23 page this manual

http://www.lgdonziclassic.com/pdfs/HM200.pdf


not sure what you mean by a RH drive most of the ford volvo setups were standard automotive rotation not reverse rotation

Gerk
05-05-2015, 10:23 PM
Sorry Matt. What I mean is the helm is on the right. Same with my buddys when I said LH drive, his helm is on the left.

Gerk
05-05-2015, 10:25 PM
I find it interesting that it makes much difference on the LH or RH prop where the helm is located.

Time to go to prop school

mattyboy
05-05-2015, 10:35 PM
for the most part the helm was located on the side of prop rotation to counter act prop torque rolling the boat the early classics were the only boats at the time that had left hand helm due to the fact that the volvo could spin left no merc product did that a marketing plan for Jim Wynne who had a monetary interest in volvo . thats why the 16 outboard is right hand helm most if not all outboards at the time spun RH. build a standard rotation ford set the volvo to the side of the helm and forget it.

if you do a lh prop on rh helm you may need some trim tab to counter act the torque very common on merc driven restored classic that are lh helm

mattyboy
05-05-2015, 10:48 PM
here is a pic of the reaction of the boat to the rotation of the prop

the prop is spinning left torque causes the boat to roll to the right so put weight on the left side to counter act that, lh helm with the weight of the driver on the left side of the boat

Gerk
05-06-2015, 12:25 AM
That makes total sense.
I am going to try the 15x19 titan and see how we do.

My new donz is not going to be ready for a few weeks. Will this prop be OK to throw on my buddys boat to see if he should buy one too.
He does have trim tabs. Will it react a lot different in the long run? With both of us in the boat, maybe not huh?

Gerk
05-06-2015, 02:07 AM
OK. I bought a 19RH titan
Think I got a good deal
$200 brand new

mattyboy
05-06-2015, 06:37 AM
the solas titan for the AQ volvo is 15 and 5/8th not 15 make sure you are getting the right prop from the seller 200 bucks is a real deal if it is the right prop


15 sounds like the saturn not the titan use this page to get the part numbers the easy way to tell you are on the right page is the titan is the only stainless that comes in a 23 pitch for the AQ the saturn and new saturn don't


http://www.solas.com/newweb/propeller/search/volvo.asp?cat=E&SKindNo=S07&Skind=VOLVO%20PENTA%20AQUAMATIC%20SP%20STERN%20DRI VE

Gerk
05-06-2015, 10:48 AM
Matty, Sorry bout that.
it is the Titan

Solas Prop Volvo Penta 15 5/8'' 19'' Pitch Titan 3 Blade Right 8841-156-19

boatnut
05-11-2015, 08:43 PM
Matty, Sorry bout that.
it is the Titan

Solas Prop Volvo Penta 15 5/8'' 19'' Pitch Titan 3 Blade Right 8841-156-19

Thanks to all of you and especially Matty, we will also be heading in the Titan direction when we put the boat back together with the Volvo 250. This thread is very interesting in that I knew about and heard about the late great Griz's prop design work and how effective it was. However I didn't know you could still get the props. And secondly I didn't realize until this thread that the diameter was 15 5/8". That helps pull it all together for me. All of the props we tried and experimented with (cupping etc.) when we were racing the Volvo drives were 14" diameter. And we all realized that the lower unit shape at higher speeds was literally blowing the water out and starving the props of solid water to bite into. (nose cones and speedmasters mitigated this to some degree) Using a larger diameter prop is logical and brilliant as the tips of the prop get more water bite with a given amount of blow out from the "club-like" lower unit. Those of you that are of my vintage realize that the Volvo stock lower units were superior to the Mercruiser drive lower units until the TRS and Bravo drives came along (about 1975). Anyway, Titan here we come. We will likely be under 300hp so a 19" is probably a good starting point -- does the design allow repitching to something like a 20" pitch? Ed

mattyboy
05-12-2015, 10:22 PM
Grizz said the props were pretty much perfect out of the box and any money spent trying to tweak one would be a waste the early props acted much bigger than the number the 19 acted like a 21 the 21 acted like a 23 and the 23 like a 25
They are hooked to the water the newer production props are shaped slightly different but they are closer to the number so a 19 with 7% slip acts like a normal 20 with 10-12% slip and that is the key how much more can you tweak out of a prop that has single digit slip numbers???? You will find that the 19 on a 240-290 hp classic with 1.6 gears will be a good prop once you want more you need to figure out how to turn a 23 past 5000 rpm on 1.3 gears I think Bills work on his 16 pretty much sealed the fate of an AQ in my mind for running over 70 with 1960s tech

mattyboy
05-13-2015, 07:23 PM
from the archives think these are maddad's props

difference in size left solas right ultra

Gerk
07-12-2015, 12:02 PM
So I wanted to post my results with the Solas Titan 19 - Feel like this should be a start of a new thread but so much has already been written here.

My 18 got put on the backburner slightly, so we tested on my buddy's 18.
That is one wild prop. Still working on dialing it all in.

It was a rougher day on the water than I would have liked to test a prop, but not awful.
Starting out at a slower pace is terrible. Tons of cavitation. Felt like just spinning and not moving.
Eventually we got moving and it is a smother feeling ride. Feels like its going faster, but I think we lost 1 MPH
We were definitely airborn more than we are typically and we got a bit sideways on a few of those.

Toward the beginning of the testing his bennett trim switch broke (great timing) so we had no trim tabs other than at the all the way up possition

We ran 5000 RPMs at 49 MPH
We found that giving it a lot of throttle from idle get up and goes very fast so no cavitation there. Going from cruising speed to WOT throws you in the engine compartment. Fantastic acceleration.


The original 14 x 19 Volvo prop to use seemed like a safer and slightly faster prop although the titan was a more fun prop. We are still working on it.

Does this review sound right or should we have gotten a 21? We just can't seem to break that 50 MPH mark (without going Bravo) He was thinking maybe his engine runs between 300-350 HP


Thanks all

boatnut
07-12-2015, 01:08 PM
So I wanted to post my results with the Solas Titan 19 - Feel like this should be a start of a new thread but so much has already been written here.

My 18 got put on the backburner slightly, so we tested on my buddy's 18.
That is one wild prop. Still working on dialing it all in.

It was a rougher day on the water than I would have liked to test a prop, but not awful.
Starting out at a slower pace is terrible. Tons of cavitation. Felt like just spinning and not moving.
Eventually we got moving and it is a smother feeling ride. Feels like its going faster, but I think we lost 1 MPH
We were definitely airborn more than we are typically and we got a bit sideways on a few of those.

Toward the beginning of the testing his bennett trim switch broke (great timing) so we had no trim tabs other than at the all the way up possition

We ran 5000 RPMs at 49 MPH
We found that giving it a lot of throttle from idle get up and goes very fast so no cavitation there. Going from cruising speed to WOT throws you in the engine compartment. Fantastic acceleration.


The original 14 x 19 Volvo prop to use seemed like a safer and slightly faster prop although the titan was a more fun prop. We are still working on it.

Does this review sound right or should we have gotten a 21? We just can't seem to break that 50 MPH mark (without going Bravo) He was thinking maybe his engine runs between 300-350 HP


Thanks all

Thank you for keeping us in the loop. We are on a similar path. Although our 18 is not together yet we are making good progress. I just ordered a Titan (21"LH) as I need the prop to figure out how to mount it on the 250 drive. The 19 vs 21 decision was difficult and time will tell if we made the right choice. The data Matty provided indicated that the Titan seems to fit into the formulas as if it had about an additional inch of pitch so the 21 could be too much for us. There are so many variables. Coincidently with our 302 H&M engine (which was probably somewhere between 200-235 hp, I think closer to 200 based on lots of data) and with a 1.61 Volvo 250 drive using a Johnson 14x19 bronze prop (slightly modified Volvo design prop) we were running close to 5000 rpm and 49 gps. We did a lot of things to the engine (GT40 heads, stroker crank, hyd roller cam) and on the dyno we are seeing about 285 hp with a very flat torque curve between about 3000 and 5000.
We thought we would be over 300 hp but the dyno is calibrated and more like gps speed compared to our optimistic hp guesses. We are several months away from splashing the boat but the water testing will tell the story. Your comments on the boats handling with the Titan did not seem too good to me. We do not use tabs and use the middle adjustment for drive trim and this boat has always been a pleasure at all speeds with a good hole shot for skiing etc. Hopefully the Titan does not screw all of that up or we will be using it as a spare. Thks for the data, Ed

mattyboy
07-13-2015, 12:40 PM
Cavitation is one thing I have never seen on a Solas Titan they are usually hooked up to the water and love rough water no ventilation or cavitation
Are you sure you have the right prop and. Not another version for the AQ

woobs
07-13-2015, 04:46 PM
Here is the formula to see what your 1.6 looks like on paper at 19p and 21p at rpm.

mattyboy
07-13-2015, 06:03 PM
something else to think about if he is making 300-350 he should be spinning a 19 way past 5000 rpm

going from a solas 19 to a 21 is going to be more than a 200 rpm drop it will be north of 400 rpm


using http://www.rbbi.com/folders/prop/propcalc.htm


plug in your numbers the more accurate the better use 7-8% slip for the solas using 4600 1.6 21 and 7% i have you at around 52-53 mph

Gerk
07-13-2015, 09:39 PM
The prop I ordered is Solas Titan #8842-156-19

I have to remember that high altitude plays a huge role up here. Boats that can do 50 up here can easily do 60 down at sea level. I was expecting however to get more than the stock prop.

Are you guys saying to move to a 21? I'm not sure how many more props I can buy haha. Guess I should buy more Donzis to put these props on.

woobs
07-14-2015, 12:57 AM
You might want to look around and see if there is a prop specialist near your location.

We have a company near here that when you bring him your boat you can spend all day testing props with their "experts" to narrow down to just the right one. Then you buy it.... you're kinda committed to at that point. But, you get the right prop!

mattyboy
07-14-2015, 07:58 AM
having a prop or two on hand is all part of Donzi Classic ownership, the hulls are very prop sensitive. I forgot about your altitude you numbers are close to mine but I am around 240-250 ish HP and a much bigger boat. If you like fast and loose the 22 ultra may be a prop to look at Hill also makes a prop for the AQ .

Woobs has a good idea if there is a shop that will help you for a sale that is the way to go.

when looking for a prop your idea of handling and slip are the big factors. usually 10% slip is the target number I have run faster props than the solas but could only take advantage of that extra speed for seconds in the right conditions and could not keep tract of all the handling quirks.

run your numbers thru the prop calc the ultra runs at about 15% slip and can go higher the faster you spin it. I would think going up to a 22 ultra would keep you around the rpms you are now maybe a bit lower I would say no lower than 4800. the bow will come up it will ventilate in harder turns and rough water but when you can find calm flat water you can fly the boat it will be fast and loose. I ran a 22 and 24 ultra on my 16 and it wasn't a bad prop but was a handful when pushing it or when having to make quick adjustments.

not knowing your motor and the altitude going to a 21 solas may put your rpm down to low 4500 or so

mattyboy
07-14-2015, 08:26 AM
I know you are looking for a magic prop to give you 3-5 mph more but those gains are usually with a shorty drive or HP

take the worst case in going to an ultra 22 -600 rpm for the jump of 3 inches of pitch ( 200 per inch) + 200 for the smaller diameter puts you at -400 rpm to 4600 rpm on your setup with 15% slip guess what you are right back at 50 mph

take the worst case in going to an solas 21 -400 rpm for the jump up in pitch and a push on diameter, turning a more efficient prop that 4600 rpm at 8% slip gets you to 52

again just a guideline and not taking in the thin air

and this is all about WOT not taking into account for mid range cruise and ride.

Gerk
07-16-2015, 11:29 AM
I had my buddy talk with the shop that rebuilt his engine.
They said it was beefed up to 350 HP
I am guessing the 19 may have been too small?

I wish we had a prop shop close enough where we could test some different ones.

Just Say N20
07-16-2015, 01:22 PM
Assumptions; an 18 with the same drive/engine will be 2-3 mph faster than a 16.

I did extensive testing with Solas props, running a 19" and 21" on my 16 Ski-Sporter with a 260 hp 350 Chevy and a Volvo 290 with power trim.

Several things you said don't match my personal experience at all.

1. Both the Solas 19" and 21" functioned at around 3% slip.

2. The Solas prop was the most "hooked up" prop I have ever run.

3. Ventilation is NOT an issue, with 15-5/8" diameter, and huge blade surface, I would believe it virtually impossible to ventilate on a stern drive.

4. The Solas is the least sensitive to trim of any round ear prop I have run. Trimming the drive up makes very little difference in the boats actual ride attitude.

5. The Solas is designed to run the boat very flat, with very minimal bow rise.

My 260 hp engine turned to 19" Solas to 5,000 rpms, and 53.7 GPS mph. The 21" Solas brought the rpms down to 4,750.

When I replaced the engine with a 430+ hp 409 monster, it would turn the Solas 23" to 5,300 rpms at 65.3 GPS mph. I have heard that strong engines in 18 Donzis running over 5,000 rpms with the Solas 23" put them over 70 mph. I ran an Ultra 26" with this engine, which ran to 5,800, but 64.7 mph.

The Ultra 24" prop also ran the 260 hp engine to 5,000 rpms and 57.3, but it was a total handful, with a ton of bow rise to minimize wetted surface. It was faster, but almost nowhere near as efficient at cruise.

Gerk
07-16-2015, 01:49 PM
you put a 409 430HP in a 16? Holy crap that must've been quite a ride.

I don't know what to say about it. That is the way it rode. I loved it, my buddy hated it. Part of this is for testing the prop for my boat as well. I will not be pushing 350 HP and my boat is a Barrelback (which I heard was lighter than the x18s.)

The outdrive trim bolt is in the 3rd position all the way out. Does that make a difference?
Holding the steering wheel also is a bit of a challenge. It cranks the boat to the left hard. You really gotta hold on.

He is afraid he is going to bury the nose as well as the prop really lifts the back end puts the bow down.


I guess we will keep trying to dial it in.

Just Say N20
07-16-2015, 03:50 PM
It was a handful only because of the inherent looseness of the Volvo helmet style steering, and because I had a traditional cable system, rather than hydraulic.

I suggest you try the Solas in the middle pin hole. The Solas is designed to make the boat run flat. They don't like to be trimmed up. That could be the source of the instability. They run very counter-intuitively. I have pretty decent seat time in many fast outboard and stern drive boats, and that experience made running the Solas MORE difficult for me to get the most out of because the "normal" rules don't seem to apply.

If your friend is used to having to trim a drive out to the max to get the best top speed, he is going to have to erase that thinking with the Solas props. Part of the reason they made the 16 more manageable, is because they were designed to run the boat flat; there was more hull in the water, adding to the stability at perhaps a slight loss in top speed because of the increase in wetted surface.

Just Say N20
07-16-2015, 03:53 PM
One last thought regarding the steering wheel torque. I had an advantage because of the power trim. I found that at almost any speed, except wide open, I could tap the trim button and find a setting that resulted in no wheel torque. The drive trim was ever so slightly different at different speeds. What was perfect at say 40 mph, was not good at 30, or 50 mph.

Too much trim at WOT is going to create a torque monster at the steering wheel!

mattyboy
07-16-2015, 06:09 PM
kinda hard to test props on two different boats with different HP and Different bottoms

i would move closer to the sea 350 hp down here is a high 50s low 60s classic

Gerk
07-16-2015, 08:52 PM
I think we will try to move the trim pin to the middle and see how that goes. On my XK22 I just moved the trim bolt to the 3rd position and it now has a lot of wheel torque. I am going to move it back.

I know Matt you are right. Originally when I thought we had very similar HP motors is what I meant. I didn't know his was beefed up so much.

Tough to move away from the cleanest nicest lake in the world for a few MPH

mattyboy
07-18-2015, 01:36 PM
when I did most of my prop testing and purchasing/ collecting I used the donzi community as a resource plus I had a friend who had a 19 cig with a volvo 270 so we went partners on most of the props . he had a LT1 CC sbc putting out around 350 hp and I had a 351w and a 250 volvo at around 310 hp. so we were close the 16 and the cig 19 are basically the same bottom. when it came to the larger props 24-28 pitch my ford with its low end torque could get up on plane but couldn't turn them at higher rpm the LT1 seems to have more ballz at the higher rpm band. after testing all the round ear , clever ,chopper, and ultra props we settled on a 22 ultra for me and a 24 ultra for him then the solas came out in 2005 or so we had a prop fire sale and i went with a solas 21 and he went with a solas 23 which put both of us in the high 50's and would hit 60 in the right conditions

things to keep in mind like Bill said if there are any issues with slop in the steering the solas is going amplify them I never had a torque steering issue with my solas but my steering was pretty tight

I did run a 25 chopper that made my right arm twice as big as my left