260 prop question
#1
Thread Starter
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Joined: May 2007
Posts: 780
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From: Staten Island, NY
hey guys i'm finally getting comfortable enough to run my boat in the upper end more often. i noticed now that i'm only getting 4400-4500 rpm out of the boat. it is a 375hp 496, its supposed to be good for 4800 i've. i'm running a 28"p 4 blade bravo, i was under the impression it was a 26"p. if i switched to a 26"p would this affect it the way i think? (extra 400 rpm and maybe a couple mph) also how would it affect midrange performance?
thanks in advance
thanks in advance
#2
Crazy Energy
Joined: Aug 2007
Posts: 4,334
Likes: 1
From: Oklahoma God's country no one else wants it.
hey guys i'm finally getting comfortable enough to run my boat in the upper end more often. i noticed now that i'm only getting 4400-4500 rpm out of the boat. it is a 375hp 496, its supposed to be good for 4800 i've. i'm running a 28"p 4 blade bravo, i was under the impression it was a 26"p. if i switched to a 26"p would this affect it the way i think? (extra 400 rpm and maybe a couple mph) also how would it affect midrange performance?
thanks in advance
thanks in advance
I will have to do the same thing on mine but I'm starting at 34 Pitch 4 blade Bravo one.
Last edited by Velocity Vector; 09-15-2008 at 12:14 PM.
#4
Crazy Energy
Joined: Aug 2007
Posts: 4,334
Likes: 1
From: Oklahoma God's country no one else wants it.
A 26 P is actually a 25P 4800 RPM 14% slip shows 65 MPH 12% slip is showing 67 MPH
Your 28P is actually a 27P so @ 4400 RPM and 12% slip you should be going 66 MPH now and 68 MPH @ 4500 RPM
I would call a blade co and get the 28 labbed instead of buying the 26.
Your 28P is actually a 27P so @ 4400 RPM and 12% slip you should be going 66 MPH now and 68 MPH @ 4500 RPM
I would call a blade co and get the 28 labbed instead of buying the 26.
Last edited by Velocity Vector; 09-15-2008 at 03:17 PM.
#5
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Joined: May 2007
Posts: 780
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From: Staten Island, NY
another member may lend me a 26p (thanks in advance bill!
)....... my 28 is supposed to be lab finished (by merc. i guess).... i've gotten 68.1 on the gps with my current setup and the tach was at 4400.... i think i'm going to try the 26 and see how it changes performance....
thanks vec.
by the way how do you calculate this stuff?
)....... my 28 is supposed to be lab finished (by merc. i guess).... i've gotten 68.1 on the gps with my current setup and the tach was at 4400.... i think i'm going to try the 26 and see how it changes performance....thanks vec.
by the way how do you calculate this stuff?
#6
Crazy Energy
Joined: Aug 2007
Posts: 4,334
Likes: 1
From: Oklahoma God's country no one else wants it.
another member may lend me a 26p (thanks in advance bill!
)....... my 28 is supposed to be lab finished (by merc. i guess).... i've gotten 68.1 on the gps with my current setup and the tach was at 4400.... i think i'm going to try the 26 and see how it changes performance....
thanks vec.
by the way how do you calculate this stuff?
)....... my 28 is supposed to be lab finished (by merc. i guess).... i've gotten 68.1 on the gps with my current setup and the tach was at 4400.... i think i'm going to try the 26 and see how it changes performance....thanks vec.
by the way how do you calculate this stuff?
http://www.go-fast.com/Prop_Slip_Calculator.htm
If I can turn my 34P act a 33P @ 5800 and 12% slip I'm looking @ 106 MPH.
Last edited by Velocity Vector; 09-15-2008 at 03:53 PM.
#7
Registered
Joined: Nov 2003
Posts: 302
Likes: 0
From: Little Silver,NJ
another member may lend me a 26p (thanks in advance bill!
)....... my 28 is supposed to be lab finished (by merc. i guess).... i've gotten 68.1 on the gps with my current setup and the tach was at 4400.... i think i'm going to try the 26 and see how it changes performance....
thanks vec.
by the way how do you calculate this stuff?
)....... my 28 is supposed to be lab finished (by merc. i guess).... i've gotten 68.1 on the gps with my current setup and the tach was at 4400.... i think i'm going to try the 26 and see how it changes performance....thanks vec.
by the way how do you calculate this stuff?




