30p vs 28p ware on drives
#1
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Guys, I just had Wesco Racing Engines build me a pair of 575s out of my old hp500 blocks. The powerplants rock, but I'm now trying to dial in. Just ordered a set of 30 pitch four blade props to replace my 28s (need to lower the RPMs), but am concerned that this will put added stress on my stock bravo drives. How much harder will 30s be than 28s?
Before you answer – yes, I know that I am putting too much horsepower through these drives. You don't need to rag on me for that! I'm just interested in knowing the difference in ware and tear between the two.
Before you answer – yes, I know that I am putting too much horsepower through these drives. You don't need to rag on me for that! I'm just interested in knowing the difference in ware and tear between the two.
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I don't see either one being harder on the drives. You will have less acceleration with the 30P and may be out of your targeted RPM range. What I do is run the 28P and then have BBLADES tweak the 28's to align with your targeted RPM. It is not that many more $ if you buy a used set of Bravo 1 28p, and then use Brett to set them up to meet your goals. In a high preformance boat, used props and BBlades provides the best value to gain max preformance.
Last edited by BenPerfected; 06-09-2015 at 05:18 PM.
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Arcticfriends "Smitty" has some informative posts concerning his real life experiences with different pitch props on a Bravo drive. I believe he noticed a significant difference in wear going from a 30 pitch Bravo prop up to a 32 pitch Bravo prop. Do a search on his threads,
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Guys, I just had Wesco Racing Engines build me a pair of 575s out of my old hp500 blocks. The powerplants rock, but I'm now trying to dial in. Just ordered a set of 30 pitch four blade props to replace my 28s (need to lower the RPMs), but am concerned that this will put added stress on my stock bravo drives. How much harder will 30s be than 28s?
Before you answer – yes, I know that I am putting too much horsepower through these drives. You don't need to rag on me for that! I'm just interested in knowing the difference in ware and tear between the two.
Before you answer – yes, I know that I am putting too much horsepower through these drives. You don't need to rag on me for that! I'm just interested in knowing the difference in ware and tear between the two.
Also, i believe Merc stuck XRs behind 600sc motors
Last edited by JRider; 06-09-2015 at 10:02 PM.
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You're right about the torque and shock load. I'm very careful with it getting on plane and hammering down while running 3700 to 4000 RPMS or so, as that's where peak torque happens.
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I find it hard to believe that a 575 Merc would make peak HP at only 5000 RPM. I would think it would be at least 5400. Were these engines built using 575 parts or something close? If it was me I would raise the limiter to 5700 and see what it does.at 5400.
I spin my 509's 6000 RPM and they love it. I wouldn't worry about 575 HP going through a Bravo drive. I was using 28 Bravo props on my 34 SCARAB and the only part I broke on the drives was a design failure of the IMCO vertical shaft in the -2 shorty's.
I spin my 509's 6000 RPM and they love it. I wouldn't worry about 575 HP going through a Bravo drive. I was using 28 Bravo props on my 34 SCARAB and the only part I broke on the drives was a design failure of the IMCO vertical shaft in the -2 shorty's.