38 special
09-11-2013 | 04:48 PM
#2
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Joined: Oct 2008
Posts: 1,689
Likes: 115
From: Slidell, La.
what drives to you have? 1.5 or 1.35? either way, something is wrong, you can not be running 68-70 at 4300 with 23p props. Is that GPS speeds?
Slip #'s on 1.5 drives are -9% at 68 and 2% with 1.35 drives.
seems like your rpm gauges are way off..
Using 1.5 drives and 23p props w/ 9.4% slip (which I get in my 33ol) would put your rpms at close to 5200??
>>>To answer your original question, 25p 3 blades will bring your rpms down lower. Rule of thumb: going from 3 to 4 blade in same pitch should bring you down about 100 rpms where as going from up 2 inches in pitch will bring you down 400 rpms. So in your case bring you down another 300.
if your not using gps for speeds and rpm gauges are correct, you need to try 21p mirage plus (3blade) or 22p bravo 1's (4b)
I will be testing some 24p b1's this sat coming down from 25p M+ to get some more rpms.
Slip #'s on 1.5 drives are -9% at 68 and 2% with 1.35 drives.
seems like your rpm gauges are way off..
Using 1.5 drives and 23p props w/ 9.4% slip (which I get in my 33ol) would put your rpms at close to 5200??
>>>To answer your original question, 25p 3 blades will bring your rpms down lower. Rule of thumb: going from 3 to 4 blade in same pitch should bring you down about 100 rpms where as going from up 2 inches in pitch will bring you down 400 rpms. So in your case bring you down another 300.
if your not using gps for speeds and rpm gauges are correct, you need to try 21p mirage plus (3blade) or 22p bravo 1's (4b)
I will be testing some 24p b1's this sat coming down from 25p M+ to get some more rpms.
Last edited by nailit; 09-11-2013 at 04:53 PM.
