Propeller for 18 Donzi

[Mitch Pixley]

I have an 18 2+3 Classic with a small block producing about 330hp and a Alfa out drive with a 1:50 to 1 gear ration. Currently I'm turning a 23 pitch cleaver with some added cupping from DAH Custom Propellers. Performance is nearly 60mph at about 4,700 RPM's. I keep hearing of other similar boats/HP that acheive top end speads of plus 70 MPH. Any propeller comments to improve top end performance is appreciated.

[BlownCrewCab]

Have you tried any round ear'd props? Like a mirage, or mirage plus? I think they'll carry the nose better and give more speed. try a stock one that hasn't been cupped allot and your rpm should go up a little as well as your speed.

[ky-donzi]

I agree with Blown CC. I have the same set up as you with the exception of a Bravo-1 drive which is suppost to be slower than an alpha. Im turning a mirage plus 25p. getting about 68 mph out of it GPS.

[BigGrizzly]

Actually a TurboI or a TXP will enhance both speed and handling. BTW without a shorty and 330 HP you won't break 70 mph

[mphatc]

Ky_Donzi, how much HP do you have ?

Grizzly, that's very valuable measurement point 330 HP in an 18 is just short of 70 mph, matches up with my past performance numbers .. a bit . . I ran a 71 GPS at 333 HP dyno numbers
Bravo 1, using Poodles 24P LH Labbed Hydromotive, but only for a short distance :(

With my new CMIs and AFR heads and compression raised 2 points . . . just what prop should I run???:confused:

Mario L.

[ky-donzi]

Mphatc

I've got a 350mpi mag. It is a 98' with 330hp at the crank.

[DickB]

I've got a '99 350 MAG. Pretty sure it is rated 300 HP. I run 62 anytime and 64.9 best ever with the stock Mirage Plus 23P at 5000 RPM. Perhaps I should try more pitch for a bit more speed?

[BigGrizzly]

Mario, knowing you and your dyno guy, I would like to see you try a TXP, 25, then work from there, if it doesn't work well. It all depends if you like the handling of the prop. I prefer them on 18.

[BigGrizzly]

People, just remember, handling goes hand in hand with speed. I have driven boats that handled so uncomfortable that I could not hold the throttle on long enough to obtain max RPMS. Most of the 18 I have driven like Turbos better than M+, However I have driven one that was the other way, and I don't know why, it just was. My Criterion hates the M+, even the passengers notice it.

[jstokes8407]

I will post when I get the boat out for the 1st time this year. I have a 350 with about 330hp , Alph SS outdrive and run a 25p 4 blade balistic. The boat moves good

[osur866]

Grizz say I have a 25p m+ turning 5100 rpms what would a 25p txp do in relation to the m+ higher or lower rpm's what do you think? And is the txp faster or just better handling than the m+ thanks

[tice652]

I have the 350mpi mag with a bravo and a 23 pitch Mirage. 68 -69 mph gps at 5100rpms. handles a little loose at that speed but I don't stay up there very long. I'd love to get her over 70 but I am having a tough time justifing boat upgrades when my pregnant wife wants new flooring and a nursery before september.

[The Hedgehog]

I have the 350mpi mag with a bravo and a 23 pitch Mirage. 68 -69 mph gps at 5100rpms. handles a little loose at that speed but I don't stay up there very long. I'd love to get her over 70 but I am having a tough time justifing boat upgrades when my pregnant wife wants new flooring and a nursery before september.

The nursery is important! The flooring on the other hand, should wait. Kids are hard on all types of floors (J/K). 68-69 is great speed out of the 350 mag. To really get that thing over 70 (and do it well), you will need a shorty.

[BigGrizzly]

Due to the the way the TXP performs and reduces the whetted surface it may go faster and actually raise the rpms due to the handling. Remember trim and balance of the boat play a big part. I can't give a solid answer to the question without leaving myself open to the "my boat does this statement". It all comes down to How you like it. If the M+ is what you like by all means use it. Don't say it is the best unless you have compared it to others props under the same conditions. After I got my Criterion sorted out I tried 15 different props on my boat and narrowed it down to 3. I prefer the TXP under most conditions. The funny part is all three are different pitches.

[tice652]

Hedghog, Im definatly a few years away from affording a shorty but I have considered having it bored to a 383 stroker - never heard of it done with an mpi though -