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Effects of prop rotation on RPM

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Old 05-21-2002 | 06:24 PM
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From: Elizabethtown KY USA
Default Effects of prop rotation on RPM

99baja posted he turns more RPM with his props turning in than he does when he turns them out, a difference of 150 RPM for him.

For those of you that have tried turning them both ways, what has your experence been in regards to any difference in RPM?

I am aware of the bow lift - stern lift issues with turning them one way or the other, but have never heard of that much difference in RPM just from changing the prop rotation.

Any help and info on this will be appreciated.

Thanks,
Mark
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Old 05-21-2002 | 07:15 PM
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Default HEY Mark

Don't know too much about twins but maybe they are picking up r's when it lifts the transom up. I know when I put on my Imco 2" shortie I went up two pitches in prop.

See ya soon
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Old 05-22-2002 | 09:16 AM
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Mike,

You may be right. I just haven't heard of the RPM change up until now. May have to break down ant try it and see what happens. Adding 150 RPM would be nice. I have the room before the limiters.

Your 2" shorties will have somewhat the same effect as extension boxes, and I know that my boat with boxes and same power will turn more prop than I do. Should have done the boxes from the factory but the price scared me to much then. However if I had it to do over I would have them. They look cool as well!

Looking forward to your visit to Cumberland. Is it still going to be around July 4th? Anybody else comming with you?

Say hi to Denise for us.

See you soon and be careful.

Mark
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Old 05-22-2002 | 06:34 PM
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Default Wes and Leslie McAllister are coming too

we will be there the whole week of the 4th.
Wes has a 91 31 311SR1 Formula with twin carbed 502's, B1 drives with 1.50 gears, 24 labbed Bravo one props.
Attached Thumbnails Effects of prop rotation on RPM-wes-les.jpg  
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Old 05-23-2002 | 09:24 AM
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Mike,

Thats great. We will be there that week also. Are you planing to stay at Grider again? I believe we met Wes last year when you were here but don't think he had his boat with him. May be wrong though. Say high to Denise and all the people that we know in your area for us (Orson & Connie, Wes etc.).

See you soon, 38 days + - !!

Mark
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Old 05-23-2002 | 11:12 AM
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From: EGG HARBOR TOWNSHIP, NJ
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yes turning them in will give you more rpm hence more speed on most boats.

Treadwell
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Old 05-23-2002 | 04:31 PM
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Default Mark

roger that to everything
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Old 05-23-2002 | 11:17 PM
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My 34 SCARAB is 3 mph faster with the props turning out.
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