04' 36 Spectre ?'s
#21
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My motors have 260 hours on them. Compresion is good, within 6% from best to worst cylinder.
Most of my boating is done on smaller water, with lots of boat traffic, so top speed is not a huge issue. My boat is 1.50 ratio, so I was wondering if I could effectively pull a 36 P Bravo One prop for the times I would like more top speed? With the 34 P Bravos my RPM is way too high.....past 6000 rpms if I pushed it. I really dont want to change the ratio at this time. My Hydromotive 33 P5 X's currently run me to 104 mph at 5800 RPMs on fairly flat water. I think it is possible to hit 110mph with 34 P5 X's at a lower RPM (5300-5400???), but I wonder how I will come out of the hole/plane. I really hate to struggle planning, just to get a better top end.
It seems that most of these boats have 1.36 ratios, and maybe that is what I should go to, but at this time I would rather just swap props........? Anybody have any experience with 1.50 ratios in their 36 Spectre PR?
Most of my boating is done on smaller water, with lots of boat traffic, so top speed is not a huge issue. My boat is 1.50 ratio, so I was wondering if I could effectively pull a 36 P Bravo One prop for the times I would like more top speed? With the 34 P Bravos my RPM is way too high.....past 6000 rpms if I pushed it. I really dont want to change the ratio at this time. My Hydromotive 33 P5 X's currently run me to 104 mph at 5800 RPMs on fairly flat water. I think it is possible to hit 110mph with 34 P5 X's at a lower RPM (5300-5400???), but I wonder how I will come out of the hole/plane. I really hate to struggle planning, just to get a better top end.
It seems that most of these boats have 1.36 ratios, and maybe that is what I should go to, but at this time I would rather just swap props........? Anybody have any experience with 1.50 ratios in their 36 Spectre PR?
#22
something doesn't seem right with your combo. You should be running in the 105 range at about 5200 with your set up. either your tachs are way off, gear ratio is not right or the props are not 34's. only other thing is you could be over trimming the boat.
#23
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The props are stamped on the barrel 34's, and the numbers match Mercury part numbers for 34's. They were on the boat when I purchased it recently. They could have been tweaked, or something.....I don't know for sure. They Hydromotive props are brand new. I know they have not been altered. Both tach's read even with each other, but maybe they could be off as well. It just seems with the 34's on, that the boat is really reving up, that I think the 6000 rpms is accurate....or close. With the hydromotives WOT is 5500-5800 at 103-104mph....definately not as many RPM's as the Bravo 34's. The side of my drives are stamped 1.5 ratio......however they could have been changed......I have not had them apart to verify the internals. I was just thinking that maybe a set of Bravo 36 would be the ticket to 110 mph at resonable RPM's. I currently have NO trouble planning with either of my current sets of props....even with me easing into the throttles. The 34's will blow out if I am not gentle, but really no issue getting up and going. Now if I could just get rid of some of that mid range porpoise.............!
#24
With a pair of 1.36 drives and 36" bravo props Zipp express ran 114-115 with 500 efi's. But those driver had tighter centers than your boat most likely has. When you get a chance, measure your drive centers, and then also take a straight edge from your running surface to the drive and measure how high that prop shaft is above the running surface. Zipp ran the best at 1.5", but the majority of the boats that went out were in the 1" range. If possible see if you can get your tach's checked for accuracy. The easiest way to determine your drive ratio would be to rotate the input of the drive until you get one full rotation on the prop shaft. Its possible that the drives could have been rebuilt with the wrong ratio. I would also have the props put on a pitch block just to verify what they really are. Most of the Bravo 1 props that I have seen measure about 2" less pitch then what they are stamped. (unless they are labbed)
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cigarette275
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02-27-2006 11:39 PM