Kalaazar

Can anyone help me here please.

I am running a handed pair of Mirage Plus 25" pitch props on Bravo 1 drive with an "X" -2" at 31" centres.

The engines are new 383ci based on new Dart blocks and heads.

All forged internals, stainless steel marine exhausts, Comp Hydraulic roller cams with a compression of 9.1 :1 plus 750 cfm Holley marine carbs.

Cam peak is 5500 rpm

Here is the issue.

With Spinelli over hub 3 blade 14 x 26" cleavers at 5800 RPM = 71.5 mph and easy out of the hole.

With Mirage plus 25" pitch 5100 RPM 75 MPH but beyond painful to come out of the hole.

Can Mirage Plus props be made to perform out of the hole with a high "X" diamention please and if so how ?

Many thanks

Kalaazar

Griff

I would try some 23 Mirage Plus props. They should spin about 400rpms faster to your 5500rpms and come out of the hole better.
Top speed should stay about the same with the 2" pitch decrease and 400 rpm increase.

Kalaazar

Appreciated, thanks.

Holy Smokes

iTrader: (2)

Try what Griff said and also call BBlades for their input.

http://bblades.com/

01scarab29

What's your prop shaft height ?

Kalaazar

My Bravo drives are 2.5" up on the X dim.

Kalaazar

Many thanks for your input, appreciated.

01scarab29

I'm not up on X dim. but I have done a lot of trial and error the past few months. with prop shaft parallel to bottom of boat, how many inches bellow or above is the prop shaft from bottom of boat. I have learned on 3 blade props they shouldn't pierce the water surface. Are you twin engines with V hull

Kalaazar

Hi, I will measure the shaft height from the bottom of the hull this weekend. This is a twin Bravo 1 installation in a Magnum27 Sport.

To date the very best overall propeller performance is with a pair of Spinneli 3 Blade outboard cleavers.

These are very easy to plane out, fair top speed, but have a high slip percentage and a few to many revs. Size 14" x 26" 1.5 : 1. 5850RPM = 71/72 MPH every day.

Kalaazar

My propeller shafts are 5" to the centre below the bottom of the hull on the drive fore and aft centre line.