Best prop for a 18 Classic

[Luca45]

Hi all:

Got my first donzi last week, a 1986 18 classic with a 1999 350 Magnum. Right now it has a Mirage SS prop, but to be honest, I don't know the other specs on it. If i was to go for a new one, what have you all found to be the best prop on this boat? thanks!

Luca

[tamburello]

Luca, congrats on the new ride! I'm by no means in the league of prop gurus on this board but I'll share what I know. I have a '94 18 with a 350 Mag and I am currently running a 24 Turbo 2+2 our blade wheel on my rig. I was previously running a 3 blade 23 QSS.

Three blade props will generally give you more top end speed than a four blade. However, the four blade dramatically improves rough water stability, balances the hull, and doesn't blow out as easily. I tested a number of different 3 and four blade props from Turbo at AOTH III and found the ride improvement to be a worthy exchange for an extra bump on the top end.

I have heard a lot of praise for the Hydromotive Quad IV on this board. Run a search of the archived articles for more insight. Have fun with your new toy!

[Rootsy]

Luca,

i run the quad IV on my 16... it is a great stability prop and i love it for that reason. Versus the mirage it is A LOT more prop to try to spin because of the extra diameter and blade. therefore you need to step down at least 1 inch in pitch when going to that 4 blade and expect to give up about 2 or 3 mph.

I have not given any of turbo's 4 blades a shot mainly due to lack of hubs installed at AOTH... otherwise i would have.

on my 16, other than the turbo 1 which runs "ok" and cleavers most other performance 3 blades are not fun to drive... the 18 handles them much better though with the extra length, etc...

Also,

if you look between the blades on the side of the mirage you should see a series of numbers stamped in the outer hub followed by a two digit number and a P... the last number and P stand for teh pitch of the prop. the first series is the model number.

[Budman]

Rootsy: what kind of top end speed do you get out of your Classic 16?

[Zinger]

Luca, that the same set-up as mine 86 classic with a 99 350 mag mpi alpha . The boat has a 23 mirage plus and runs greats with this set-up , but if I,am pulling a skier or a tube i need a smaller pitch the 23 is a dog. Just curious what a 86 with a 99 mag is worth. Jeff

[Rootsy]

Budman,

last year with the alpha GEN II and the 23 Cleaver spinning 5400 rpm i saw 68.0 GPS... that was on the ragged edge of fun... you had to DRIVE the boat...

anything other than WOT with a cleaver is way inefficient... and just plain blows generally.

This year with the Alpha SS and three tenths of a point in compression ratio boost i've seen a BEST with a BONE STOCK 27P quad IV O/T of 76.1 @ 5500 rpm and 75.8 GPS with a labbed 25 Cleaver spinning 6K... with the 25P quad IV i spin 5500 and i've seen 75.1 GPS... the quad IV is 3/4 inch larger in diameter than the O/T (15 1/2 vs 14 3/4).

the quad IV gives me 8 - 9% actual slip.. across the board.. from plane on up to WOT... i love the cruising part.. 3500 rpm and 49 mph...

my 350 IS NOT stock... and soon to be less stock still... so i will probably need a 27 quad IV next spring :D

Root - Mr. twister...