What Direction To Go?
 

I Have A 38 Scarab (1998) That Im Currently Running 27p Mirage Plus On!About 625hp Running Standard Bravo 1.5!I Broke A Couple Of Drives Last Year So I Am Installing Xrs With 2" Shorties That Are 1.36!What Direction Do I Need To Go With In In Prop Pitch And What Kind,i.e. Blade Number! Thanks For The Help!This might help,the boat weighs about 10k-the motors wot is 5200 at 75mph!The 27p work pretty good with good bow lift just braking the drives are the problem so with the xrs and shorties and gearing I hope to run less pitch which I hope will be less strain on the drives!Just which direction??THANKS AGAIN!!

Re: What Direction To Go?
 

Can you post your old set-up numbers, please.

Julie

Re: What Direction To Go?
 

old setup is (maximum wot of 5200rpm,according to owners guide) (motor are 525sc with pulleys and coolers which make about 625hp) (boat weighs about 11k) (drives are standard bravos with 1.5 gears 4" below hull) (props are mirage plus 27p) (boat runs 75 mph at wot of 5200 maximum)

new set up is(2" shorties with 1.36 gears)

now i just need to know what prop to go with on the new setup or atleast a starting point

THANKS AGAIN

Re: What Direction To Go?
 

With the old set up slip at over 15%, you will need 4 blades to control the efficiency at the elevated drive height. Changing gear ratio and drive height at the same time makes the learning process slower. You will gain rpm with the height and lose it with the gear ratio. Actually raising the drives can put more strain on them if you are surfacing the props. Distance between load can affect this even more with the Mirages.

Run t6he props you have and then let's discuss your findings.

Re: What Direction To Go?
 

That Sounds Good!the Only Problem I Have Now Though Is The Props I Have Now Have A Solid Hub And Are For The Smaller Shaft!the New Drives Have The Larger Shaft And Will Not Fit!im Going To Try And Borrow A Few Set Of Props To Find Out Which Works Best But I Have No Idea On What To Ask For!thanks For The Input Though!

Re: What Direction To Go?
 

Let us know if you need to test some props. We have a number of props in our test prop program that may work for you.

A good prop to start with may be a 28 Bravo 1 to get some baseline numbers to work with.

Matt

Re: What Direction To Go?
 

Took the boat out today with the new drives installed!

The set up is 625hp x2 with 1.36 gears,boat ways about 10-11k,air temp was about 66,120 gallons of gas,2 adults,prop shafts are 6" below hull,and finaly I was using bravo1 24 pitch props out of the box to get an idea of were i need to go!

It took little while to get on plane and at about 3000 rmp the nose would finaly fall over!Once moving we were doing 50 at 3400 rpm which seems like a good cruise,when we got to 60 the rpms were 4000 and when we hit 70 the rpms were 4800!

I could not go wot and fully trimmed because the Pacific was a little rough today !MY guess is when we would hit 5200 which was the max with my standard drives and 27 mirage plus we would be realy moving!

I feel i need to go bigger in pitch but what too?26 OR 28? thanks JUSTIN

Re: What Direction To Go?
 

Sorry I missed this earlier.

With the 24's trimmed out you may be at the right rpm. This would mean Lab Finished 26's may just be the ticket. Your slip % is good. If you liked the way they handled, stay with the Bravo 1's.