Performance Update

[Just Say N20]

It is a beautiful day in Western Michigan. It has been about a month since I bought the boat, and decided it was time to splash it.

Although I have owned two 18s, I have only ridden in one other 16, and that one has an H/M engine and a Volvo 270 with an e-drive.

Both the 18s ran 57/58. I was told the boat ran 62 with one of Grizz's secret special props. Grizz, I will be saving my pennies to buy one from you. The previous owner has had a change of heart about selling me the one from this boat. As I mentioned before, that didn't come with the boat.

I didn't know what to expect with the aluminum prop, but I figured low to mid-50s as that is what the HO 4.3 V6 does in the current 16s.

This boat has a Volvo 290 outdrive with trim (maybe all 290s have trim, I don't know).

If the TACH is right, here is what I got.

Sunny, 73 degrees.

23% relative humidity

30.06 barometric pressure

15 mph wind creating less than 1' of chop

725 feet above sea level

4,900 rpms @ WOT

47.2 mph GPS mph


This is not what I expected. This is my 15th boat, so I have a better than average understanding of running boats fast. The trim was working, as I would feel the boat freeing up as I trimmed up. At the "up" limit of the trim, the prop wasn't even close to breaking loose.

I believe the MAX rpm for the Volvo HO engine is a little higher, but I am going one what the previous owner told me. I have not checked for myself.

This is for information purposes, as I'm not looking to "solve" anything here, yet. The engine loves to start easily, but it misses (no back firing) when throttle is applied. If WOT is applied from rest, the engine labors some to get the boat on plane, and throttle response is sluggish.

After a 2 minute run, I checked the engine compartment, and there was a moderate amount of burning oil smoke coming from the port, transom side of the engine. Further inspection revealed I could move the entire port exhaust manifold (stock Volvo) ever so slightly, from side to side. This baffles me, because there was no leaking exhaust sounds, or "blown gasket" sounds.

I got to use my "tight quarters tow vehicle" to get it in the garage.

I almost got a self initiated Dumb A$$ of the day award. A while back there was a post regarding the proper set up of the winch, etc. at the front of the trailer. I contributed, commenting on how important it was to have the winch strap UNDER the bow stop, so in the case of a panic stop, the boat wouldn't be able to run forward, possible up into the tow vehicle.

So, MY trailer is not yet set up this way. AND it is a roller trailer. So today when the guy in front of me decided to literally slam on his brakes, so he could make an illegal U-turn (to the point that the anti-lock brakes on the Magnum were doing their thing big time), I got to watch in horror as the boat came about a foot forward, riding up the bow stop. :eek: :eek:

Then, as I accelerated away, I watched the boat gently roll backwards on the trailer until the winch strap was again tight.

I will be fixing that immediately.

[Sweet Cheekz]

Glad to see you got it out Bill
I just ran from Grand Haven to Port Sheldon and back making about ten passes by the Grand Haven peir. What a day!
Where did you run today?
Was this speed from the speedo or gps? How long did you stay in it at wot?
I assume although I don't know for sure that the aluminum prop is not going to give you the top end you need Also the bottom paint has to be scrubbibng speed. My freinds 95 with the 4.3 and Alpha runs 49-52 tops
Just fyi I am sure the board gods will have way more and better info Glad you got out How did it feel compared to the 18's

Parnell

[Donziweasel]

What hp is the Volvo engine? Got to remember, the original 16's only ran in the mid-upper 40's.

[Planetwarmer]

I was looking at your strap setup. It would be easy to just mount a safety strap under the bow stop and simply connect it to the bow eye after you get the boat properly loaded.

[BigGrizzly]

remember the 290 likes a lot of trim. I am not sure what prop Earl got but I think it was a 19, but that does not compute to 62 mph. The good part Is I keep them in stock and I have no intention of stopping. For now go out and have fun.

[MOP]

Bill every winch stand I have fooled like that one had a double roller that had a pivot where yours has the bolt for your roller, the strap or cable was between the rollers the stand was set to nest the bow eye under the top roller making it solid no movement winched it.

Wait until you get some of this years fuel in and Randy prop, it should jump up a bit.

Enjoy

[Just Say N20]

Thanks for the advice.

I think the winch will be an easy fix.. I can slide the whole stand forward, and then raise the "craddle" part so it is just above the bow eye. Both of these adjustments can be made easily, by the design of the trailer. I have some fine tuning of the trailer to do anyway. The nose of the bow doesn't fit into the middle of the trailer. I have to move the roller racks on the bow to the right a little so the boat will be centered on the trailer.

Been a while since I used a roller trailer. Yikes! The boats really come off of them easily.

Parnell, the speed was GPS. Because the exhaust manifold was loose, and there was oil from somewhere creating continuous smoke, I opted not to push it too hard. I ran it in Reeds Lake, and went from the far end to the ramp at WOT to get the max speed reading. Glad you had some fun running yours today. I think you pretty much convinced me to split the boat to do the repairs. Now that it appears the engine needs some attention, I would much rather pull it with the deck off. Be easier to "de-rust" and repaint as well as check things out. 16 vs 18? I didn't run it anywhere near enough to make any judgment, just from the ramp to the other end and back. That's it. At it was very calm, just a slight wind chop. Sucker is LOUD though.

I ran the drive up until it hit the limit switch before the trailering tilt kicked in. Hard to tell for sure, because the digital drive trim indicator was all over the map, from -8 to +16, at the same setting.

I was told the Grizz prop was a 21" pitch, but I'm not really trusting much from the source any more. Each new "fact" I get to personally test turns out to be, well, not factual. I'm having a hard time believing a prop change would increase top speed from 47 to 62. I would love to be surprised that way. That would be the cheapest 15 mph speed increase anyone ever bought!

MOP, I'm thinking the double roller setup you mention is the way to go. They pivot in the middle, and the winch strap runs between the upper and lower rollers. I'd love to get some ideas about securing the transom. I have always had bunk trailers, and would use tie down straps at each corner. On this trailer, the body of the trailer stops about 2 feet forward of the transom. The rollers come out almost to the transom, but not the trailer frame. I would also have to add the hardware to the transom as it is bare except for the outdrive. No biggie.

DW, I was told the engine/Volvo 290 Drive package was installed around 1984, and was supposed to be right around 300 hp. That is more than either of my 18s had, and they both run 10 mph faster. I have heard people say that with equal power, for some reason the 18 is faster than the 16, but this seems like too wide of a margin.

[mattyboy]

welcome to the world of old volvo driven 16's


if you felt in control at all times and the boat did not become squirrely or down right awnry you are not pushing the boat.

the old 16's at around 52 mph took on a life and mind of their own using the technology of the time best put by Brownie "they don't chine walk they gunwale walk!"

now with trim and newer prop technology the 16 would break it's old service envelope.


yes a prop can make up 10 mph or more on a volvo setup. I have a garage full of props that do different things and have different top ends and handling characteristics


the 16 is no 18


run the numbers I have for your setup and if all is right tach motor ,running a 21" prop with 10% slip 60 is attainable at the standard 4800 rpm limit


Grizz i think it was a 19 i don't think that setup will turn one of your 21's


and a note to all who use one of grizz's props you have to add 2 inches of pitch or your slip numbers will not jive they are actually grip numbers if you don't ;)

[mattyboy]

http://www.donzi.org/forums/showthread.php?t=191

my 16 was almost the same setup less the trim I bet the nose cone closed that gap a little mine was a 310hp motor

[MDonziM]

Thanks for the advice.

I think the winch will be an easy fix.. I can slide the whole stand forward, and then raise the "craddle" part so it is just above the bow eye. Both of these adjustments can be made easily, by the design of the trailer. I have some fine tuning of the trailer to do anyway. The nose of the bow doesn't fit into the middle of the trailer. I have to move the roller racks on the bow to the right a little so the boat will be centered on the trailer.

Been a while since I used a roller trailer. Yikes! The boats really come off of them easily.

Parnell, the speed was GPS. Because the exhaust manifold was loose, and there was oil from somewhere creating continuous smoke, I opted not to push it too hard. I ran it in Reeds Lake, and went from the far end to the ramp at WOT to get the max speed reading. Glad you had some fun running yours today. I think you pretty much convinced me to split the boat to do the repairs. Now that it appears the engine needs some attention, I would much rather pull it with the deck off. Be easier to "de-rust" and repaint as well as check things out. 16 vs 18? I didn't run it anywhere near enough to make any judgment, just from the ramp to the other end and back. That's it. At it was very calm, just a slight wind chop. Sucker is LOUD though.

I ran the drive up until it hit the limit switch before the trailering tilt kicked in. Hard to tell for sure, because the digital drive trim indicator was all over the map, from -8 to +16, at the same setting.

I was told the Grizz prop was a 21" pitch, but I'm not really trusting much from the source any more. Each new "fact" I get to personally test turns out to be, well, not factual. I'm having a hard time believing a prop change would increase top speed from 47 to 62. I would love to be surprised that way. That would be the cheapest 15 mph speed increase anyone ever bought!

MOP, I'm thinking the double roller setup you mention is the way to go. They pivot in the middle, and the winch strap runs between the upper and lower rollers. I'd love to get some ideas about securing the transom. I have always had bunk trailers, and would use tie down straps at each corner. On this trailer, the body of the trailer stops about 2 feet forward of the transom. The rollers come out almost to the transom, but not the trailer frame. I would also have to add the hardware to the transom as it is bare except for the outdrive. No biggie.

DW, The engine/Volvo 290 Drive package was installed around 1984, and was supposed to be right around 300 hp. That is more than either of my 18s had, and they both run 10 mph faster. I have heard people say that with equal power, for some reason the 18 is faster than the 16, but this seems like too wide of a margin.


Its been a long time since I owned her but it was a Volvo 311/290. stock 311 hp. 5200 redline. I spun a 27" stainless prop with a nose cone to 5200. Had no gps then, but it was every bit of 60mph and was very much on the edge.

[Just Say N20]

if you felt in control at all times and the boat did not become squirrely or down right awnry you are not pushing the boat. the old 16's at around 52 mph took on a life and mind of their own using the technology of the time best put by Brownie "they don't chine walk they gunwale walk!"


I am asking in a sincere, humble manner. If the drive is trimmed to the limit, and the throttle is wide open, what should I be doing to "push the boat?" I didn't try, but I could have probably let go of the wheel and continued happily down the lake, so there was definitely no bad behavior.





now with trim and newer prop technology the 16 would break it's old service envelope.

yes a prop can make up 10 mph or more on a volvo setup. I have a garage full of props that do different things and have different top ends and handling characteristics

I look forward to experiencing this. My only experience with the Volvo outdrive was with the 270 (no trim) on my X-18. The boat ran 57 with a prop that looked very similar to the one on this 16. I expected similar performance with this set up. I'm not sure I can put how the boat felt into words, but it felt "wrong." It felt like the prop was actually fighting the engine, trying NOT to convert engine rotation into forward thrust. The prop appears to be in good condition with no nicks, bends, folds or irregularities that would suggest it shouldn't perform well.




remember the 290 likes a lot of trim. I am not sure what prop Earl got but I think it was a 19, but that does not compute to 62 mph. The good part Is I keep them in stock and I have no intention of stopping. For now go out and have fun.

There have been a couple of suggestions to really trim this drive. I don't believe there is anything beyond trimming until the limit switch kicks in. I went out and trimmed the outdrive to this point with the boat on the trailer, and it has a decent amount of trim.

I will have to conclude that this prop doesn't have the bite to actually provide much lift. I could feel the hull loosen up, but it never achieved enough lift to cause the hull to porpoise.

I will have to get a substantially different prop before I can go out and enjoy the boat. :frown: The little jet I just sold had better acceleration and a higher top speed than this, as well as a higher comfortable crusing speed. Another thing that suggests to me this prop isn't doing the job, is that the rpm/speed numbers don't seem right. To cruise at 35 mph, I had to be running 3,700 rpms. Again, I don't know if the TACH is accurate, but this is the best information I have at the moment.

[Just Say N20]

Marshall,

I believe you are the person who selected the color scheme when the boat was repainted. It is very unusual, and I'm really starting to like it. :cool!:

Bill

[MDonziM]

Marshall,

I believe you are the person who selected the color scheme when the boat was repainted. It is very unusual, and I'm really starting to like it. :cool!:

Bill

I can't really take credit. It was supposed to be a more typical Donzi yellow....just didnt turn out that way. It is unique.

[Tony]

Your prop sounds like the big-old aluminum tug-boat style, with a pitch of 19 or maybe even less. Strong hole-shot, but no top end, and very high rpm's.

My '67 Ski Sporter had similar power, and ran best (for top-end) with a cupped 23" Volvo Ultra. (I sold it before trying any of Randy's props.) Topped out just north of 60 mph, and it was definitely a white-knuckle experience! :shocking:

There's a boat/sport shop in Grand Rapids, on Alpine south of I-96 I think, that sometimes has used Volvo props. Can't think of their name right now but it may come to me. Maybe you can try an aluminum 21", or even a 23", for pretty cheap money, to see how much propping is the problem.

:beer:

[Just Say N20]

I can't really take credit. It was supposed to be a more typical Donzi yellow....just didnt turn out that way. It is unique.

The best laid plans. . . . :yes:

[Just Say N20]

Your prop sounds like the big-old aluminum tug-boat style, with a pitch of 19 or maybe even less. Strong hole-shot, but no top end, and very high rpm's.

My '67 Ski Sporter had similar power, and ran best (for top-end) with a cupped 23" Volvo Ultra. (I sold it before trying any of Randy's props.) Topped out just north of 60 mph, and it was definitely a white-knuckle experience! :shocking:

There's a boat/sport shop in Grand Rapids, on Alpine south of I-96 I think, that sometimes has used Volvo props. Can't think of their name right now but it may come to me. Maybe you can try an aluminum 21", or even a 23", for pretty cheap money, to see how much propping is the problem.

:beer:

Tony, I think you are referring to Van's. Great place. They actually installed the nitrous on my second 18. Very honest people. Tom Sr. sold the business, but the new owner seems to be carrying on in the same tradition.

When I went to pick the boat up after the nitrous installation (we had developed a relationship by this point, as I had a constant stream of boats I had been taking to them), the bill was less than I expected. I asked why, and he told me he didn't feel right charging me their full labor rate, as they had never done a nitrous install before, and he felt it took longer than it should. I could go on and on with examples like this. I recommend them to EVERYONE.

Thanks for the suggestion, but I think I'm going to just wait until I can get one of Grizz's props. If it is known to work well, you know, buy the best and you won't be disappointed.

[mattyboy]

If I recall correctly the drive didn't have a nose cone, the drive i looked at on that boat was a 1.3 ratio which would be very hard to spin a 27 to 5200 and if it could it would be well north of 70 never mind 60.
so some time after Marshall had the boat the drive or lower must have changed.

I believe Earl had one of the 27 or 28 pitch SS props and couldn't get on plane with them

Marshall's descritpion is dead on once the 16 hull is up and aired out it feels on the edge, loose, demands every bit of attention the furthest thing from your mind would be the I can just let the wheel go. you will know once you get there. and the 16 is going to scare you it happens to everyone going along fast hit a wake or a roque wave and it it will get out of shape. I told this to the guy I sold mine to he laughed and shrugged it off it happened to him about 2 weeks later almost tossed a passenger . i saw him at the quickie mart sometime after and said did it scare you yet, his wife's face went white as said I told you it would. the 16 is a very capable boat but it does have some bad manners at times

running your numbers it is probaly like a 16 or 17 pitch prop that is on there now you need to confirm tach, motor , drive ratio and what prop you have

[Just Say N20]

running your numbers it is probaly like a 16 or 17 pitch prop that is on there now you need to confirm tach, motor , and what prop you have

Where do I find prop numbers on a Volvo prop?

There is no nosecone on the lower unit now. Marshall noticed this in some of the first pictures I posted, and wondered about it too. The funny thing is that I can't see any evidence that there ever was a nose cone on this particular unit.

You had mentioned before that you thought this was a 1.3:1 ration drive. If the lower unit had been replaced/changed since Marshall owned the boat, could the ratio be different than what was on there when he was spinning the big prop. I guess the real question is are the gears that determine the ratio in the lower unit, or the upper?

[mattyboy]

lower, they make 2 ratio for 8 cyl apps

1.6

and 1.3


with a 1.6 you can turn bigger pitched props and Marshall description is in the ball park a 27 pitch at 5000 or so rpms and you are in the 60's

[Just Say N20]

Found the number.

C 854980

14 X 23

Something isn't making sense.

[MDonziM]

I still have a lot of the engine/ drive package paperwork from the 87' install but nothing on the drive ratio. I agree with Matty, I think it was a 1:6 because I am certain my memory is correct on the prop ( ss "ear shaped chopper") and the rpm. I dont know why the drive ratio would have been changed unless spinning a smaller pitch prop faster made the boat behave better. Again, it was a serious handfull the way I had it setup.

[mattyboy]

I still have a lot of the engine/ drive package paperwork from the 87' install but nothing on the drive ratio. I agree with Matty, I think it was a 1:6 because I am certain my memory is correct on the prop ( ss "ear shaped chopper") and the rpm. I dont know why the drive ratio would have been changed unless spinning a smaller pitch prop faster made the boat behave better. Again, it was a serious handfull the way I had it setup.


yes it it was an ear shaped chopper Earl had , I had the same prop but in a 25 pitch with me when i looked at the boat for him, i think he might have even run my 25 that weekend as i recall the serial number on the drive said it was a 1.3 and it behaved like it



they have not made a michigan 23 pitch prop in sometime now I would bet it has had some work done to it over the years, the decreased diameter makes sense for the lower ratio but working the numbers the pitch on the prop is off an inch ot two or your tach is off by a grand

[Just Say N20]

they have not made a michigan 23 pitch prop in sometime now I would bet it has had some work done to it over the years, the decreased diameter makes sense for the lower ratio but working the numbers the pitch on the prop is off an inch ot two or your tach is off by a grand

I got the diameter/pitch number from a Volvo link. Are you saying the prop was made for Volvo by Michigan Wheel? It is an aluminum prop that was coated with what feels like a thick teflon type coating that is flaking off.

If the lower unit was replaced, then the number on the drive doesn't matter.

Is there a way to mechanically measure the ratio without pulling the drive?

I will have to test the accuracy of the TACH.

[mattyboy]

I got the diameter/pitch number from a Volvo link. Are you saying the prop was made for Volvo by Michigan Wheel? It is an aluminum prop that was coated with what feels like a thick teflon type coating that is flaking off.
If the lower unit was replaced, then the number on the drive doesn't matter.
Is there a way to mechanically measure the ratio without pulling the drive?
I will have to test the accuracy of the TACH.


Michigan did alot of work for the aquamatics,whats the number on the drive??? last time i saw it it had newer volvo graphics on it, newer than 87, does it have the angled cap on the upper???

mark a spline on the prop shaft then get the motor to turn over once then see how far the mark traveled, not sure of an easy way to do this without pulling the drive, the plugs, or getting stuck in the bilge,, the testing on all the lowers I had was done by pulling the drive and turning the input shaft once and then seeing how far the prop shaft spun 1 and a 3rd or 1 and a little more than half or 1 and a little more than 3/4 or over 2

I would find a known prop run it get the numbers once you verfy the tach and run thru a calculator to get you ratio on a volvo michigan alum prop I would use 15% slip


this is handy

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


using your numbers if it is a 23 pitch prop and 15% slip you have a 1.93 drive ratio give or take a few digits in slip could mean a 1.8 or a 2 something drive with 300 ponies you would be redlining that sucker would be screaming with a 6 cyl or 4 cyl outdrive ratio

[Just Say N20]

Matty, I appreciate all your input/help.

Thanks for the link to the prop calculator. IF the tach is correct, and the listed outdrive ratio is correct, and my GPS is accurate, I have to be at about 27% slip.

Pictures. I don't know how you would describe the top of this drive. A picture is worth a 1,000 words.

Drive plate says:

Volvo 290A

Serial # 853086

I'm guessing drive ratio: 1,61

And I included pictures of the lower unit. You see things I don't, but I don't see any evidence that there was a nose cone on this lower unit.

[mattyboy]

usually the A denotes a ratio of 1.3
A 1.3
B 1.6
C 1.8
D 2.1

but Volvo did make some 4 cyl only drives with "5" like a 275A drive
not sure if that is the case with the 290

as I said it behaved very much like a 1.3 drive when I saw it

does the motor have a rev limiter? I ask cause if would need to have one if it was a 1.8 or 2.1 drive as the motor would be able to spin way past 4900 rpm with a 23 pitch prop. if it does have a rev limiter and you go with 10% slip , 23 pitch and a 2.1 drive ratio your numbers work but with this scenario the motor would wind up fast . but if it were a 2.1 drive with that motor it should have been able to get a 27 pitch up on plane???

the numbers are also in the ball park for a 1.3 with a 18 or a 19 pitch and 15% slip.

volvo props are not very effecient so I think 12-15% slip is being conservative they are more like 15-18% slip

[Just Say N20]

The engine didn't run like it was hitting a rev-limiter. Marshall remembers running it to 5,200.

I have asked BigGrizz to see if he can find records of what was on it before, as that is what worked.

[mattyboy]

if you are only spinning what we think is a 23 to 4900 and you want to be up at 5000 or 5100 take your ego and check it at the door you will have trouble spinning anything but a 19 from grizzly that fast , but a 19 is really more of a 21 , 21 is more of a 23, and the 23 is more of a 25

the solas don't suffer from the lack of efficiency like the other volvo props they are around 5-8 % slip, on larger V bottoms they are a tad slower than an ultra but only a tick or 2 but they handle much much better especially in a 16 they don't give alot of lift but carry the boat at a very flat angle and give you a little more wetted surface for better handling manners

[Kirbyvv]

I was testing Grizz's props at Lake George at the same time as Earl. I think he went with a Solas 19". I'm spinning a Solas 21 to 5000 rpms with a stock 350 on my X-18. 1.6 ratio.

[Tony]

If it's the 1.3:1 ratio drive...therein lies the problem.

:beer:

[Just Say N20]

I was testing Grizz's props at Lake George at the same time as Earl. I think he went with a Solas 19". I'm spinning a Solas 21 to 5000 rpms with a stock 350 on my X-18. 1.6 ratio.

I'm hoping Grizz has records of what he sold. Then all this other stuff becomes unimportant.

Time for a new thread I think. This horse is about dead. :yes:

[DonziJon]

pulling the drive and turning the input shaft once and then seeing how far the prop shaft spun 1 and a 3rd or 1 and a little more than half or 1 and a little more than 3/4 or over 2




Matty: I keep getting confused with gear ratios. Are you saying that the gear ratio (whatever it is) in an outdrive will always spin the prop Faster than the engine RPMs?

ie; With a 1.5:1 ratio,... the prop will spin 1500 RPM when the motor is spinning 1000 RPM. Is that correct or do I have it backwards? Just trying to understand. John

[Just Say N20]

Matty: I keep getting confused with gear ratios. Are you saying that the gear ratio (whatever it is) in an outdrive will always spin the prop Faster than the engine RPMs?
ie; With a 1.5:1 ratio,... the prop will spin 1500 RPM when the motor is spinning 1000 RPM. Is that correct or do I have it backwards? Just trying to understand. John

That is backwards.

1.5:1 = 1500 engine rpms will turn the prop shaft 1000 rpms.

1.61:1 = 1.61 engine rotation will turn the prop shaft 1 rotation, etc.

That is why if my set up is 1.3:1 it will have a harder time with a larger pitch prop.

[mattyboy]

Jon, sorry can't answer that the horse is dead. :horse:


you have it bassackwards


a 1.3 drive ratio means the motor turns 1.3 times and the prop once

[DonziJon]

Thanks guys. I got it now. Prop turns Slower than the engine. :yes: John

[DonziJon]

the testing on all the lowers I had was done by pulling the drive and turning the input shaft once and then seeing how far the prop shaft spun 1 and a 3rd or 1 and a little more than half or 1 and a little more than 3/4 or over 2

So Matty, did I get it Wrong .....or is YOUR Description Bassakwards? :nilly:
.............................Just pullin your chain Matty. :yes: John

[mattyboy]

yeah I meant to say turn prop shaft once and see how far the input shaft travels or a guees you could turn the input shaft too until the prop shaft turns once


you pulled my chain now go talk politics or go sailing