prop for 16 classic

[ATLDONZI]

i know its been beaten to death but what is going to be the best all around prop for my 4.3lx 16. i currently have a vengence 23p and it spins way to high when trimmed out way over 5k and only shows 46 on the speedo.... this definatley dosent seem right. i would like a higher top ens but have good cruising as well...


thanks in advance

[CrackerJack]

If you are turning 5k rpm's with a 23pp and a 1.84 drive ratio, you should be going approx. 54 mph with 8% prop slip. To get an accurate speed you will need a gps unit. For a 16' Donzi, the 23p mirage plus is probably the best prop for all around performance. I believe the prop you have is a smaller diameter prop than the mirage and that may be why your top end is low, even though you are at 5k rpm's.

[ATLDONZI]

anyone had any experience with a laser prop?

[CrackerJack]

Yes, but the Mirage plus 23p has better performance.

[ATLDONZI]

ok so i double checked today on the lake and at 4900-5000 rpms on the GPS i was going 53.5-54.1 mph but i still had throttle left but i didnt want to bounce the rev limiter. i checked again today my prop is actually a 19P vengence not 23( i feel retarded)... again its a 4.3 lx merc with an alpha everyone i have talked to said the 23p mirage plus is for bravo drives, try a 21p laser II

[CrackerJack]

The Mirage plus 23p is what came on our 16', 4.3l LX Gen+ with an alpha drive and a ratio of 1.84. Do you know what drive ratio your alpha is? Because, when I use the prop formula the numbers you have don't calculate correctly for a 1.84 drive ratio, and that is what comes with a
V6.

That may be why you have a 19pp and not the 23pp. If your drive ratio is lower you would not be able to spin the higher rpm's with the larger pitch prop. Also, for each single size increase in prop pitch your rpm's will decrease 150-200 rpm's.

This is the prop formula.
http://www.rbbi.com/folders/prop/propcalc.htm

[Sam]

Try a Turbo, very stable and good perfomance from top to bottom. From my experience the M+ was very unstable at high speeds.

[Rootsy]

Try a Turbo, very stable and good perfomance from top to bottom. From my experience the M+ was very unstable at high speeds.

you can say that again....

[smokediver]

the laser2 is ok with the v6 ... i will say that there is way too much slip as the horsepower is increased ... the mirage plus has better slip numbers as the diameter is bigger ... the laser2 is only 13 3/4 diameter ... my 25 mirage is faster in every range compared to my labbed 27 laser ... i did have a 24 turbo on my v6 and liked it but i prefer the mirage plus ...

[ATLDONZI]

what diameter miarge plus, and on the turbo what pitch and diameter and where to get one? thanks in advance

[CrackerJack]

Do you know what drive ratio you have?

[ATLDONZI]

1.81 ratio...thanks for your patience... i have searched and found lots on the subject but little definitive answers

[Mr X]

Using the numbers you posted in post 5. It is impossible for your drive ratio to be 1.81 to 1

It calculates to a 1.50 to 1, with an 8% slip factor

Exactly what Crackerjack was saying in post #6 above.

[RedDog]

Using the numbers you posted in post 5. It is impossible for your drive ratio to be 1.81 to 1
It calculates to a 1.50 to 1, with an 8% slip factor
Exactly what Crackerjack was saying in post #6 above.

physics give most a problem.

Each variable must be confirmed and then an intellegent answer or suggestion can be provided.
1 - what drive and ratio
2 - what exact prop brand, pitch and diameter
3 - actual RPM (correct) and speed (GPS or radar verified)
4- and one that isn't usually thought of - is there a current in the water you are running

Without firm establishment of the above it's all a guess

[BigGrizzly]

STOP, What matters is the right prop regardless, we know he has a 19 Vengence, we know it is too small. What we don't know is if the prop has been messed with. If the lower unit says 1:81 than it should be. however Ted's numbers are good except I have found that prop to have about 10-12% slip on that application. I prefer the Turbo, or the Solas Lexor. Try a 23 M+ or a Turbo or Lexor and go from there. Rember "Theory is good but honest testing is truth"! This way we know where we are nd which way to go from here. Ted and I have had a little more experience in the prop area than most and we still don't have all the answers. So lets not confuse the situation lets get the solution. Pressure uses a 23 on his 16, Jack what did you use on your stock V6? get these answers and go test WITH a GPS.

[ATLDONZI]

STOP, What matters is the right prop regardless, we know he has a 19 Vengence, we know it is too small. What we don't know is if the prop has been messed with. If the lower unit says 1:81 than it should be. however Ted's numbers are good except I have found that prop to have about 10-12% slip on that application. I prefer the Turbo, or the Solas Lexor. Try a 23 M+ or a Turbo or Lexor and go from there. Rember "Theory is good but honest testing is truth"! This way we know where we are nd which way to go from here. Ted and I have had a little more experience in the prop area than most and we still don't have all the answers. So lets not confuse the situation lets get the solution. Pressure uses a 23 on his 16, Jack what did you use on your stock V6? get these answers and go test WITH a GPS.


thanks, also do you know of any good prop exchange programs in GA

[BigGrizzly]

I'm him as of Saturday I'm the largest stocking dealer in GA for Turbo. you can come up with your boat and we can test. I live on lake lanier. 770-318-1136

[CrackerJack]

Randy, if you take the numbers he has in post #5, and use a 12% slip factor he should be doing around 44 mph not 54+mph. I have found that the prop formula is pretty accurate for the 16'. If he tries the Mirage Plus 23p, which I had on my 16' when it had the V6 and he can still turn 5000 rpm's he should be doing around 55 mph (we could only turn 4800 rpm's). I agree that this is not an exact science, but props cost $$$$$$$, so maybe he can hook up with you and try some different props. I have used the Mirage Plus 23p, and I believe a Laser 21p or 23p. The Mirage worked good in both fresh & salt water except the Laser, and it caused problems in fresh water.:confused: I now have a V8, and the Mirage Plus 23p starts chin walking over 60, the Vengence 23p is better. I now am trying a Turbo 23p I got from some guy (BG) that had a bunch of props in his SUV in Sarasota.:cool:

[BigGrizzly]

Trying props is where it is at. otherwise your guessing. Remember my boat with aTRS and a nice motor, flat flys and the prop does it as much as the engine! I made the invitation. Now it is up to the Donzi-ites.

[ATLDONZI]

I'm him as of Saturday I'm the largest stocking dealer in GA for Turbo. you can come up with your boat and we can test. I live on lake lanier. 770-318-1136


where abouts on lanier are you... i am on the south end near holiday.. i will be on hartwell this weekend but after that i would be forever in debt if you could help me out. thanks


chris