New Props NEEDED!
 

Im Looking For A Set Of New Props!currently Im Running Mirage 3 Blade 25 On My 1998 38 Scarab Powered By 525sc's,I Do Have Smaller Pulleys And Am Running Superchillers And 1.5 Gear Ratio!mid 70s At Wide Open Throttle!whats The Next Pitch I Should Try And How Many Blades?Would A 25 Four Blade Be Better For More Top Or Maybe 26/27??My Set Up Should Get Me 80 With The Right Prop But What Would That Right Prop Be?

Re: New Props NEEDED!
 

Any Body Have Any Ideas??

Re: New Props NEEDED!
 

I was hitting 5800 with a set of 25 P Mirages. Switched to 26 four blade Bravo1's and turned 55-5600. That's all I've got for ya....but should get you started. Call Throttle Up, they will help you out!!

Re: New Props NEEDED!
 

What gears do you have?

With 1.36 you have 15% slip and with 1.5 you would have 6% which is unlikely. With the 525's you need to run at 5380 at WOT. So you need to drop down in pitch or perform some prop adjustments, such as labbing , pitch change and cup adjustment to increase your RPM.

Julie

Re: New Props NEEDED!
 

I Have 1.5 Gears,when Starting Off To Get On Plain,the Props Brake Loose Fairly Easily And I Have To Back Off The Throttles,cruise Is Good But It Does Take Some Time To Get Max Speed And When Trimmed I Do Have Quite A Roost!my Props Now Are 25mirage Plus 3 Blade,just Seems Like I Need More Bit!now With My New Set Up(pulleys And Chillers)im Wondering What Will Happen!

Re: New Props NEEDED!
 

Justin

I can only give advice based on experience. I have a '91 Top Gun with Hawk 525's. Came with labbed 27 Mirage plus 3 blades. I had the same problem coming on plane. I switched to a 26 pitch 4 blade as I need more bite for flying ocean swells. I need to lab mine as I can only spin 5100 RPM. If you would like to try the the labbed 27's, let me know.

Hugh

Re: New Props NEEDED!
 

HUGH,THAT MIGHT BE A GOOD IDEA,I AM VERY CLOSE TO YOU,I ACCUALY KEEP MY BOAT IN COSTA MESA!E MAIL ME AN ILL GIVE YOU A CALL [email protected]

Re: New Props NEEDED!
 

JJones,

I am re-reading this thread and I am not seeing your WOT RPM...Maybe I calculated your slip wrong. What is your WOT RPM? I think I got it off of the thread you deleted.

I am afraid to say that 6% is to good to be true with 3B props but if indeed this is true I WOULD NOT TOUCH those props...golden. So that being said I would verify all of your data. I would also encourage you to try some 4B props. They will carry your boat much better than the 3B props.

Julie

Re: New Props NEEDED!
 

Juile,my Wot Is About 5000 At 72mph On Flat Water!this Is Before My New Setup,i Havnt Run The New Setup Yet But With Smaller Pulleys And Chillers A Good Guess Would Be 75/76 At Maybe 5100/5200 Rpm!im Going To Lake Havasu For A Full Week And I Realy Want To Play With The Props,need A Good Direction Though! Thanks For Answering

Re: New Props NEEDED!
 

Safe Testing! Get back with us on your weekend and we can start from there.

Julie

Re: New Props NEEDED!
 

Just Got Back From Lake Havasu From A Weeks Vacation!my 25mirage Plus Would Take For Ever To Get Up On Plain!never Had Such A Problem Before!i Barley Gave It Throttle And They Would Brake Free!once I Got On Plain I Was Able To Get 5200 Rpm But Not Any More Top End Speed!a Local Boating Buddy Loaned Me Some Other Props,the First Set Was 26 Bravo1 Four Blades,they Were Brand New Still In The Box,with These Props Top End Was The Same As Well As Wot At 5200 But Getting On Plain Was Much Better,infact My Boat Has Never Plained So Easily!i Still Think I Need To Go Bigger Though!tell Me If Im Wrong But More Power Means The Ability To Spin More Prop,move More Water Faster,hence Gain More Speed!i Did Have 27labbed But They Did Not Fit,i Think They Are Trs Props!whats Next!29,30 4blades?help? Thanks!

Re: New Props NEEDED!
 

Justin
I am glad that the 26's worked for ya. I was always thinking that the labbed 28's would be best for your application You can try my Bronson Hill labbed 26's with +200 RPM someday. That should put you at your goal. Are you trimmed out?

Hugh

Re: New Props NEEDED!
 

hugh,i was trimmed out as much as i wanted to go!take off was great with the 26p,i called to bring them back,they are still in new condition,did not hit the bottom!lol,i cleaned them all up and put them back in the boxes,fresh ater tends to leave lime on stainless,so i bought some lime away and cleaned them up,i really appriciate the use of them!when can i bring them back to you?

Re: New Props NEEDED!
 

1998 Scarab With 525sc's With 7psi And Chillers/25 Mirage Plus 74mph @ 5200 Wot,Took For Ever To Plain,Never Done That Before ,kind Of Like A 357 I Had With Kammas,Infact The Surface Drives Plained Better! ......
26 4 Blade Bravo1 5200 Wot,Got On Plain Like My Jet Boat But Still Only 73/74 Mph
Fresh Water With Wind Chop
The Three Blade Mirage Felt As Is I Could Brake Them Free If Going Full Stick Rapidly While Crusing!
Engine Maximum Rpm Is 4800/5200,
Do I Need To Go Big??
The 4 Blades Worked Great But I Think The Top Should Be Alot More Or Am I At The Best With What I Have?Im Guessing The Power Out Put Is 600hp Now!
Thanks

Re: New Props NEEDED!
 

You will need to prop for peak HP, dynos will help. You have stated:

4800 / 5200 what does this mean? What is 4800?

Julie

Re: New Props NEEDED!
 

Julie, My Motors Are Rated For 4800 To 5200 Rpm, Maximum,at Wide Open Throttle,this Is What By Engine Capabilities Are Per Owners Manual Thanks

Re: New Props NEEDED!
 

Are they stock or modified motors. If you have added the superchillers and changed the pullys then you have most likely moved the peak HP. Where does your engine builder believe the peak HP is now? The peak HP is of course were your peak speeds will be.

Julie

Re: New Props NEEDED!
 

They Are Basicaly Stock Merc 525sc's With The Addition Of Pulleys And Chillers Which Should Make About 600 Hp. With Out The Pulleys And Chillers The Motors I Believe Make 500 Prop Shaft Hp!with Out The Pulleys And Chillers My 25 Mirage Plus Worked Fairley Well,getting On Plain Was Ok And Top Speed Was About 72/73
Now The 25mirage Just Spin,i Have To Be Very Patient To Even Get On Plain!the Motors Just Screem But The Boat Hardley Moved!

Re: New Props NEEDED!
 

I would say you need to run 4B props to give you better bite, or to have another blade assiting as obviously the 25P is just blowing out. I wuld recommend that you start testing with some Bravo I propellers.


Julie

Re: New Props NEEDED!
 

On My Trip I Was Able To Use Bravo1 4 Blade 26p,getting On Plain Was Much Better,best Ever But Top End Never Chainge!still In Max Rpm The Engines Allow For About 5200 And Same Top End Of About 73/75 ! Do I Need To Try Bigger Blade Props And Witch Would Be A Good Prop To Go With Next?THANKS FOR YOUR HELP SO FAR!

Re: New Props NEEDED!
 

The natural progression here is to go to 28 Bravo 1's if you can turn them.

You're missing a key question here. Besides the old recommended operating range, is your rev limiter still at stock merc setting? If so, your slip is 11%, your in the meat of the power band and you are all set. If your hitting the rev limiter, we have a whole different issue. Since the merc setting is 5400, I assume your can only pull the props to 5200?

The other consideration is Lab Finished 28's to get you the same rpm and some more cruise and top end.

Let us know if you wish to test 28 B1's.

Re: New Props NEEDED!
 

Ok Now I See ,yes I Am Pulling The Bravo 26p 4blade To 5200rpm But Not Hitting The Rev Limiter!the Rev Limiter Is Stock Setting !with 5200 Rpm Though,souldnt The Top End Change With The Addition Of More Prop?before I Added The New Goodies,my Boat Ran About The Same Top With The Mirage Plus 25 But About 300 Rpm Less!

Original Config/4800,4900 Rpm At Roughly 72/74 Mph With Mirage Plus 25p

New Engine Config With Chillers And Pulleys/5200 Rpm And 72/74 Mph With Mirage Plus 25p


Last/new Engine Config With Bravo1 26p 4 Blade Is 5200rpm And Once Again 72/74 Mph!

I Guess I Thought The Top End Would Change But It Hasnt,well Not Enough To Realy Notice, Im Always Around The 72/74 Mph Range!

Is This Just The Way Its Going To Be?? Thanks

Re: New Props NEEDED!
 

Some boats actually do have a wall they run into that requires mega hp to get through. It could be due to hook, rocker, CG or combinations of those and others.

Certain boats like certain props better. The Mirage carries the bow better and although it is "slightly" smaller in pitch it has less drag and less stern lift to it than the B1.

Both propellers are working quite well as far as the numbers go. The seat of the pants stuff, planing, cornering, quartering seas, etc. are what you need to decide the boat likes best.

My biggest question now would be, how many ponies do we actually have? If rpm verses pitch matches the speed pretty well, and it does. Hum?

The first numbers are almost too good. 73@4850 rpm 4.63%