- Joined
- Mar 8, 2009
- Messages
- 40,754
Going to try and condense a year long rebuild and 12 pages of post for hopefully some fresh ideas.
http://forums.iboats.com/forum/engi...mula-27pc-complete-power-plant-rebuild/page12
A single engine Formula 27 foot cruiser with 9 foot beam, drafts 42 inches to bottom outdrive.
Drive ratio 2.0 with Bravo 3, all speeds are GPS readings, tach was checked with computer and is within 50 rpm at WOT
Originally 415HP 502 turning 5200 RPM at WOT doing 46 MPH.
New engine is 530 HP with 3x3 26 pitch prop set WOT 5050RPM doing 46 MPH
Same 530 HP with 4x4 24 pitch prop set WOT 5200 RPM doing 47 MPH
The 4x4 gives best whole shot but prop slip is staying around the 20% mark no matter what is changed. Only thing I cannot verify is the dyno sheet provided to me showed 545 HP (5200 RPM) and 617 TQ (3800 RPM). If I have more HP and more torque why am I unable to get more?
http://forums.iboats.com/forum/engi...mula-27pc-complete-power-plant-rebuild/page12
A single engine Formula 27 foot cruiser with 9 foot beam, drafts 42 inches to bottom outdrive.
Drive ratio 2.0 with Bravo 3, all speeds are GPS readings, tach was checked with computer and is within 50 rpm at WOT
Originally 415HP 502 turning 5200 RPM at WOT doing 46 MPH.
New engine is 530 HP with 3x3 26 pitch prop set WOT 5050RPM doing 46 MPH
Same 530 HP with 4x4 24 pitch prop set WOT 5200 RPM doing 47 MPH
The 4x4 gives best whole shot but prop slip is staying around the 20% mark no matter what is changed. Only thing I cannot verify is the dyno sheet provided to me showed 545 HP (5200 RPM) and 617 TQ (3800 RPM). If I have more HP and more torque why am I unable to get more?