Go Back  Offshoreonly.com > Technical > General Q & A
Estimated HP output - Build Sheet attached >

Estimated HP output - Build Sheet attached

Notices

Estimated HP output - Build Sheet attached

Old 04-10-2018, 10:43 PM
  #11  
Registered
iTrader: (1)
 
Join Date: Oct 2013
Location: SF Bay Area
Posts: 2,885
Received 142 Likes on 94 Posts
Default

Originally Posted by Tinkerer
I got 650 HP out of my 509's with 10 to 1 compression, ported Dart heads, hyd. roller Crane 741 cam and Lightning headers. lots of other tweaks " TINKERING "
Nice! At what rpm?
Baja Rooster is offline  
Old 04-10-2018, 11:17 PM
  #12  
Gold Member
Gold Member
 
Join Date: Jul 2008
Location: Delray Beach, FL
Posts: 3,747
Received 866 Likes on 325 Posts
Default

Originally Posted by JRider
If you are going to spin the motors higher there may not be a need for different props.

+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.
Keith Atlanta is offline  
Old 04-11-2018, 10:05 AM
  #13  
Registered
Thread Starter
 
Join Date: May 2014
Location: Buffalo NY
Posts: 206
Likes: 0
Received 3 Likes on 2 Posts
Default

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).
AWOL is offline  
Old 04-11-2018, 10:16 AM
  #14  
Platinum Member
Platinum Member
iTrader: (6)
 
F-2 Speedy's Avatar
 
Join Date: May 2012
Location: Midwest & T-Rock
Posts: 10,388
Received 3,029 Likes on 1,347 Posts
Default

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 +
F-2 Speedy is offline  
Old 04-11-2018, 11:36 AM
  #15  
Platinum Member
Platinum Member
iTrader: (1)
 
articfriends's Avatar
 
Join Date: Jun 2004
Location: frankenmuth michigan
Posts: 7,130
Received 798 Likes on 366 Posts
Default

I personally think youd have to gain a bunch of tq to spin 28s if you were previously spinning 24s. Try to borrow props before you buy any if possible, smitty
articfriends is offline  
Old 04-11-2018, 01:34 PM
  #16  
Registered
 
convincor's Avatar
 
Join Date: Nov 2002
Location: CT
Posts: 532
Received 3 Likes on 1 Post
Default

You can test drive props with BBlades
convincor is offline  
Old 04-11-2018, 01:35 PM
  #17  
Registered
iTrader: (3)
 
cigrocket's Avatar
 
Join Date: Feb 2004
Location: Endicott, NY
Posts: 2,574
Received 158 Likes on 77 Posts
Default

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
cigrocket is offline  
Old 04-11-2018, 06:49 PM
  #18  
Registered
 
Join Date: Jan 2006
Location: St. Pete Beach, FL
Posts: 3,566
Received 559 Likes on 335 Posts
Default

Originally Posted by AWOL
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).
👌good boat
hogie roll is offline  
Old 04-11-2018, 08:39 PM
  #19  
Registered
 
Tinkerer's Avatar
 
Join Date: Jan 2002
Location: ALTO, MI
Posts: 4,612
Received 7 Likes on 6 Posts
Default

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.

Last edited by Tinkerer; 04-11-2018 at 08:42 PM.
Tinkerer is offline  
Old 04-11-2018, 09:20 PM
  #20  
Registered
Thread Starter
 
Join Date: May 2014
Location: Buffalo NY
Posts: 206
Likes: 0
Received 3 Likes on 2 Posts
Default

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.

AWOL is offline  

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.