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5 blade for midrange performance?

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Old 07-16-2012, 04:17 PM
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Originally Posted by miwettig
going to 5 blades cost you a drive??
Likely......you never know when one will let loose but I ran about 100 hours on 32P Bravos without issue. Within about 40 hours of installing 5 blades the boat broke both XR's. (keep in mind I was running more TQ than the XR was rated for) Slip is what keeps the drive from grabbing too much water at once......but that also means you will be slower.
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Old 07-16-2012, 08:47 PM
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Originally Posted by miwettig
keep me in the loop w/your results. How do work 'slip' numbers?
Will do
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Old 07-16-2012, 09:23 PM
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Originally Posted by miwettig
going to 5 blades cost you a drive??
Less slip equals more stress, no way around it. A few years ago I installed a stelling ext box on my boat , while trying different props I tried a 5 blade Maximus and almost immediately ( the same day I was testing the prop) sheared off a billet prop shaft, I had just inspected that shaft a few days before that too, my slip numbers were around 10 % or so with the 5 and 20% or so with the 4 blade labbed. I replaced the shaft and have ran the same amount of hp/tq (1000+ ft lbs) since then without accelerated failure, 5 blades can really torque load a drive with big hp, Smitty
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Old 07-17-2012, 05:54 AM
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Originally Posted by miwettig
Maximus?
Mine are Hydromotives.
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Old 07-17-2012, 03:03 PM
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Are Hydro's still available?
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Old 07-17-2012, 05:23 PM
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Originally Posted by mrquad1
agreed,i run 5 blades love them.little off of top end but never blow them out,also they hook up great when re-entering water!

What pitch are you running on your 38? Was going to try a Merc Maximus 24 pitch on my 42.
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Old 07-18-2012, 12:22 PM
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Mercury recommends dropping down 2" if going from Bravo I to the Maximus 5 blade...agree or disagree?
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Old 07-18-2012, 02:18 PM
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2 inches sounds right IF your using the same diameter (Maximus come 15 5/8 vs Bravos at 15 1/4)

for my application 30P Bravos were the fastest, running 86 at 5,600 rpms and 48 at 3,500. 32P Bravos were 83 at 5,300 rpms and 54 at 3,500. 28P 15 5/8 maximus were 83 at 5,250 rpms and 58 at 3,500 rpms.
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Old 07-18-2012, 02:49 PM
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Thanks for the test results. What boat, length and motor?
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Old 07-18-2012, 03:16 PM
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Originally Posted by miwettig
Thanks for the test results. What boat, length and motor?
Formula 382 fastech. 630hp/700tq motors (dyno'ed fully dressed with ALL accessories-not dyno headers and water hose in the front)


As I said in an earlier post.....the 5 blades tore up the drives IMO.
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