Dialing in the props...
#1
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Dialing in the props...
Long story short I'm ready to set up my props.
I'm running out of the box 26" Bravo 4 blades on 1.3 ratio drives, spinning out.
I calculated 9-10% slippage.
1993 42' Fountain Non step with drive boxes and -2 lower B-max's
Turning 5100rpm now and would like to see 5500...Loosing 80hp a motor with that missing 400rpm.
So...
How much rpm/mph could be gained from a lab job?
Do I need to pull an inch or so out of the pitch?
I also need more bow lift?...I over trim it now to get the bow up enough at WOT.
Does lift have to do with blade rake?...or spinning them in instead?
I'm running out of the box 26" Bravo 4 blades on 1.3 ratio drives, spinning out.
I calculated 9-10% slippage.
1993 42' Fountain Non step with drive boxes and -2 lower B-max's
Turning 5100rpm now and would like to see 5500...Loosing 80hp a motor with that missing 400rpm.
So...
How much rpm/mph could be gained from a lab job?
Do I need to pull an inch or so out of the pitch?
I also need more bow lift?...I over trim it now to get the bow up enough at WOT.
Does lift have to do with blade rake?...or spinning them in instead?
#2
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Re: Dialing in the props...
Never delt with a twin set-up, but trying many different things is the only way to really find out!! Labbing the 26's should give you 200 RPM or so. Will 3-blade props work? Some 25 Mirage's may help to get you some more bow lift. I'm really talking from my ass when it comes to getting a 42' twin engine Fountain propped. Good luck!!!
Craig
Craig
#3
Re: Dialing in the props...
Hi Mark,
Happy Holidays
Although my favorite holiday is July 4th.
The older Fountains seem to like Hydromotive props.
Guess I'd play with your Bravo props and see what you can get out of them.
If you have some time on your hands give Jim Hering a call - 360-659-4315
Fountain racing has since gone to Hering with excellent results.
Oh yeh, I have a few projects myself to attend to over the winter.
Dennis
Happy Holidays
Although my favorite holiday is July 4th.
The older Fountains seem to like Hydromotive props.
Guess I'd play with your Bravo props and see what you can get out of them.
If you have some time on your hands give Jim Hering a call - 360-659-4315
Fountain racing has since gone to Hering with excellent results.
Oh yeh, I have a few projects myself to attend to over the winter.
Dennis
Last edited by StrikinLightnin; 12-22-2004 at 09:27 PM.
#6
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Re: Dialing in the props...
You would do better by changing to 1.5 ratio drives, then dial in the props.
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Marc
www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
It's not alive -www.BoatStuffExpress.com - temporarily retired
#7
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Re: Dialing in the props...
Originally Posted by Mbam
You would do better by changing to 1.5 ratio drives, then dial in the props.
There are many considerations when making a prop selection and having prop work done. It's important to make sure that whomever you are working with understands your goals and works the prop or makes a prop suggestion that fits those goals.
Matt
#8
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Re: Dialing in the props...
Turning them in will give you more bow lift & usually a litle more speed on an older fountain. The hydromotive Q IV seems to work best. I have an old 10 meter & have played with many props.
#9
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Re: Dialing in the props...
Originally Posted by Back4More
Long story short I'm ready to set up my props.
I'm running out of the box 26" Bravo 4 blades on 1.3 ratio drives, spinning out.
I calculated 9-10% slippage.
1993 42' Fountain Non step with drive boxes and -2 lower B-max's
Turning 5100rpm now and would like to see 5500...Loosing 80hp a motor with that missing 400rpm.
So...
How much rpm/mph could be gained from a lab job?
Do I need to pull an inch or so out of the pitch?
I also need more bow lift?...I over trim it now to get the bow up enough at WOT.
Does lift have to do with blade rake?...or spinning them in instead?
I'm running out of the box 26" Bravo 4 blades on 1.3 ratio drives, spinning out.
I calculated 9-10% slippage.
1993 42' Fountain Non step with drive boxes and -2 lower B-max's
Turning 5100rpm now and would like to see 5500...Loosing 80hp a motor with that missing 400rpm.
So...
How much rpm/mph could be gained from a lab job?
Do I need to pull an inch or so out of the pitch?
I also need more bow lift?...I over trim it now to get the bow up enough at WOT.
Does lift have to do with blade rake?...or spinning them in instead?
Darin 281-580-7767
Last edited by HOUSTONPROP; 12-23-2004 at 09:25 AM.
#10
Ginger or Mary Ann?
Charter Member
Re: Dialing in the props...
Sorry to jump in ,
Darin, what would the cost be to repitch the 2) 26 hydro Q-IV's you labbed for me last spring up to 27".
Thanks
Darin, what would the cost be to repitch the 2) 26 hydro Q-IV's you labbed for me last spring up to 27".
Thanks