Estimated HP output - Build Sheet attached
#12
Gold Member
Gold Member
+1
Sold my props on the last two builds. Then, after they were tuned, I paid money to have BBlades lab me a set of new props that were the same or similar to what I sold.
If anything, its worth running the old props with new power for a baseline. Your prop guy might be able to put a little more pitch or tune and achieve more than starting with new props.
#13
Registered
Thread Starter
The boat has/had 24P Bravo 1 props prior to rebuild/additional power. I was thinking jumping to a 28P Bravo 1 would be the play. This seems to be what most people run at this power level (500HP+) and this hull (33 powerplay).
#14
Platinum Member
Platinum Member
iTrader: (6)
I ran 28p four blade on my 33 OL but I was around 620 hp...........if the 28's are to much you might try the 25p mirage +
#15
#17
Registered
iTrader: (3)
I agree with Articfriends, Not necessarily the HP, but you need some good torque curve and power to go from 24s to 28s. The best way is to either to truly dyno the motors to know what you have, or borrow some props. I would start with some 26s. Just my opinion. Good luck on getting them dialed in
#19
The 509's were spun at 5700 on the SCARAB and 6000 on the Daytona with the 1.5 ratio drive.
I run labbed Bravo 28 four blades on my Daytona. But I am spinning them with a 1.36 ratio drive and 6100 RPM.
If it were my boat I would try the original props. You will want to spin the new engine faster anyways.
You create your HP in the heads on a BBC. If you just changed heads and didn't have them ported or bought them CNC'd then you will see an increase in HP but probably not as much as you think you are going to get.
Those engines had a LOT of tinkering done to them. So there was a lot more to them than the parts I listed.
Those engines and the 598 were put together with a LOT of expensive parts and machining.
I run labbed Bravo 28 four blades on my Daytona. But I am spinning them with a 1.36 ratio drive and 6100 RPM.
If it were my boat I would try the original props. You will want to spin the new engine faster anyways.
You create your HP in the heads on a BBC. If you just changed heads and didn't have them ported or bought them CNC'd then you will see an increase in HP but probably not as much as you think you are going to get.
Those engines had a LOT of tinkering done to them. So there was a lot more to them than the parts I listed.
Those engines and the 598 were put together with a LOT of expensive parts and machining.
Last edited by Tinkerer; 04-11-2018 at 08:42 PM.
#20
Registered
Thread Starter
I guess I'll have some playing around to do. I was just thinking an estimate on power would help.
The previous owner used both 1.35 and 1.5 gearing in the Bravo drives with the old power. 1.35 for fuel economy, then switched to 1.5 for better acceleration. It was spinning the 24p to 4600 with the 1.35 gearing and old power. It was spinning 25p Mirage+ to 5000 with the 1.35 gears as well.
All things being equal, I figured by the switch to the 1.5 gearing, a 26P 4 Blade would be in order. Add in the new power, that led me to the 28p as a starting point.
I haven't picked up the boat yet, I was just thinking of starting somewhere with the props since it hasn't really been tested WOT since the rebuild.
The previous owner used both 1.35 and 1.5 gearing in the Bravo drives with the old power. 1.35 for fuel economy, then switched to 1.5 for better acceleration. It was spinning the 24p to 4600 with the 1.35 gearing and old power. It was spinning 25p Mirage+ to 5000 with the 1.35 gears as well.
All things being equal, I figured by the switch to the 1.5 gearing, a 26P 4 Blade would be in order. Add in the new power, that led me to the 28p as a starting point.
I haven't picked up the boat yet, I was just thinking of starting somewhere with the props since it hasn't really been tested WOT since the rebuild.