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Testing the 20' tomorrow!
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Testing the 20' for a second time tomorrow with different prop. New heads and valve springs! Motors running great! Running 75mph with 23 3 blade at 4500 rpms so dropping to 21 3 blade. Should be running around 5600 rpms. Still have to getting her trimmed out. Supposed to be only 50 degrees tomorrow so should hit a good number!!
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Originally Posted by cfischer
(Post 3088768)
Testing the 20' for a second time tomorrow with different prop. New heads and valve springs! Motors running great! Running 75mph with 23 3 blade at 4500 rpms so dropping to 21 3 blade. Should be running around 5600 rpms. Still have to getting her trimmed out. Supposed to be only 50 degrees tomorrow so should hit a good number!!
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Originally Posted by cfischer
(Post 3088768)
Testing the 20' for a second time tomorrow with different prop. New heads and valve springs! Motors running great! Running 75mph with 23 3 blade at 4500 rpms so dropping to 21 3 blade. Should be running around 5600 rpms. Still have to getting her trimmed out. Supposed to be only 50 degrees tomorrow so should hit a good number!!
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Here are the #'s from the prop calc, you would have to be running a 1.25 ratio drive, with 4% prop slip, nearly impossible.
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Also, how does dropping one prop size(2") add 1100 RPM??
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Originally Posted by rchevelle71
(Post 3088848)
Also, how does dropping one prop size(2") add 1100 RPM??
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Originally Posted by rchevelle71
(Post 3088848)
Also, how does dropping one prop size(2") add 1100 RPM??
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I would assume the ratio is 1.5:1 with a 1:1 tranny.
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Originally Posted by cfischer
(Post 3088867)
Do I know you??
And that's a nice 20' my friend. |
Thanks Greg,
I just wanna know what his formula for getting his 20 to do 75 at 4500 RPM, cuz, I run 5400-5800, and can only get 60 with the same prop?? I realize my 24 may be a little heavier, and I run a 1:75 gear, but I have tried everything, and cant get this pig over 60, his slip seems awful low. Think about it, we only ran 78 on a GREAT day in Tims 28, with 830 horse at 5250 running 28 Bravo's. |
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