Results of 5 Blade Maximus on my 2007 Daytona
04-23-2007, 01:21 PM
#1
Registered
Platinum MemberThread Starter
Join Date: Jul 2006
Location: Rochester, NY
Posts: 610
Likes: 0
Received 0 Likes
on
0 Posts
Results of 5 Blade Maximus on my 2007 Daytona
The season has begun!
I took delivery of my '07 28 in Sept of last year that came w/stock 4 blade merc 32's. I have twin 496HO's (stock) with Bravo drives 1.36 gear ratio.
With the 4 blade props, I was able to squeeze 100mph out of it in ideal conditions - but depending upon load, it would run anywhere from 92-98 consistently.
The center of my prop appears to be about 1" lower than the bottom of my hull. No cavitation plates. No stand off boxes.
I started the season off on Sat, and put on 5 blade 30's.
The extremely obvious difference was the hole shot. With the 4 blade and full tanks of gas, it took some serious finess to get on plane...with the 5 blade - I am up on plane easily at around 2400 RPM's and fullt anks of gas with 5 guys in the boat....with the 4 blade, I would have to move people up front to get on plane with full tanks of gas.
With full tanks of gas, I was able to get 94mph with the 5 blade - 65 degree air temp, less than 1 foot of chop.
With 1/2 tank of gas I was able to get 96mph - I have a feeling, I'll gain another 1-2 mph once I consume more fuel and get down to about 1/4 tank.
Some other interesting observations:
1. My port RPM's are about 200 higher than my starboard engine. So at WOT and trimmed up to about 3.5, my port engine will be running at 5100 while my starboard engine runs about 4900. I manually trim out the starboard, or trim in the port engine to try and synch them up, but I found this curious - any thoughts why this may be occurring?
2. Boat pulls slightly to Port at certain speeds - I notice that I have to slightly continually steer to starboard while under way at certain speeds - what do you think explains this?
I've seen other posts where people seem to be consistently breaking the 100mph mark w/496's on 28's....what do I need to do to achieve similar results - wll standoff boxes help? What kind of gains would boxes provide?
I am concerned about doing any engine mods like CMI headrers, because I just have the Bravo drives which are only rated for 450 hp I believe.
I took delivery of my '07 28 in Sept of last year that came w/stock 4 blade merc 32's. I have twin 496HO's (stock) with Bravo drives 1.36 gear ratio.
With the 4 blade props, I was able to squeeze 100mph out of it in ideal conditions - but depending upon load, it would run anywhere from 92-98 consistently.
The center of my prop appears to be about 1" lower than the bottom of my hull. No cavitation plates. No stand off boxes.
I started the season off on Sat, and put on 5 blade 30's.
The extremely obvious difference was the hole shot. With the 4 blade and full tanks of gas, it took some serious finess to get on plane...with the 5 blade - I am up on plane easily at around 2400 RPM's and fullt anks of gas with 5 guys in the boat....with the 4 blade, I would have to move people up front to get on plane with full tanks of gas.
With full tanks of gas, I was able to get 94mph with the 5 blade - 65 degree air temp, less than 1 foot of chop.
With 1/2 tank of gas I was able to get 96mph - I have a feeling, I'll gain another 1-2 mph once I consume more fuel and get down to about 1/4 tank.
Some other interesting observations:
1. My port RPM's are about 200 higher than my starboard engine. So at WOT and trimmed up to about 3.5, my port engine will be running at 5100 while my starboard engine runs about 4900. I manually trim out the starboard, or trim in the port engine to try and synch them up, but I found this curious - any thoughts why this may be occurring?
2. Boat pulls slightly to Port at certain speeds - I notice that I have to slightly continually steer to starboard while under way at certain speeds - what do you think explains this?
I've seen other posts where people seem to be consistently breaking the 100mph mark w/496's on 28's....what do I need to do to achieve similar results - wll standoff boxes help? What kind of gains would boxes provide?
I am concerned about doing any engine mods like CMI headrers, because I just have the Bravo drives which are only rated for 450 hp I believe.
04-23-2007, 04:13 PM
#2
Registered
Join Date: Jun 2001
Location: Tulsa, OK, Grand, Beaver, LOTO
Posts: 1,213
Likes: 0
Received 0 Likes
on
0 Posts
IMHO- you are right there- there are "best speeds" and everyday speeds, especially in cats- lots of variables. My old 25 Daytona had a best of 99.0, mid summer pigged out might hit 90 but usually mid-high 80's. cool temps, 93-95 any time with light load. I'ts going to take more engine if you want 100 every day
04-24-2007, 10:44 AM
#4
Seeing how the 4 blades would get you on plane I would use 1" shorter lowers and the 5 blades and see, maybe ever 2" shorties. You might have stamped 30p but if they are off slightly compared to each other can account for your rpm and pulling findings i.e. one is 30.5p and the other is 29.5p. Send them out to be checked and 'trued' and matched with or without full labbing of the props.
04-24-2007, 02:58 PM
#6
Registered
Join Date: Jun 2001
Location: Tulsa, OK, Grand, Beaver, LOTO
Posts: 1,213
Likes: 0
Received 0 Likes
on
0 Posts
FWIW- when I had my 25, thjought I was pretty easy on it, gentle planing, no air time, about 625/650 ish whippled 454 mag, lost a stock bravo upper gear at about 60 hrs, bought the boat new, not an x1/xz/xr but stock 2001 bravo, I'd hesitate to go more than 550 N/A
04-24-2007, 04:37 PM
#7
Registered
Join Date: Sep 2004
Location: LOTO 1.5mm grandglaze arm
Posts: 172
Likes: 0
Received 0 Likes
on
0 Posts
I concur with this statement. I also had 25 . 502efi/Procharger and was easy as I could be on it at LOTO and it lasted about 50 hours. after that it was all down hill.
04-24-2007, 05:24 PM
#8
Registered
iTrader: (2)
The center of my prop appears to be about 1" lower than the bottom of my hull. No cavitation plates. No stand off boxes.
Get out a long straight edge and confirm if this is true, if it is you will get more speed from a box. Buy pair of stellings boxes and you won't have to buy a shorty lower, it will put you up 2" and back about 12"
With 1/2 tank of gas I was able to get 96mph - I have a feeling, I'll gain another 1-2 mph once I consume more fuel and get down to about 1/4 tank.
Less weight = more speed no question. You should do your top speed testing on cold dry days with around 1/8 tank of fuel. As long as you can do it somewhere near a gas dock no more than 1/4. Take everything out of the boat you don't have to have by law and no passengers!
Some other interesting observations:
1. My port RPM's are about 200 higher than my starboard engine. So at WOT and trimmed up to about 3.5, my port engine will be running at 5100 while my starboard engine runs about 4900. I manually trim out the starboard, or trim in the port engine to try and synch them up, but I found this curious - any thoughts why this may be occurring?
Are the drives at the same level at 3.5 or are your indicators off? What kind of tachs do you have? Besides that i'm stumped
2. Boat pulls slightly to Port at certain speeds - I notice that I have to slightly continually steer to starboard while under way at certain speeds - what do you think explains this?
You're drives may be out of alingment or your tachs are reading incorrectly.
I've seen other posts where people seem to be consistently breaking the 100mph mark w/496's on 28's....what do I need to do to achieve similar results - wll standoff boxes help? What kind of gains would boxes provide?
See above, also if you don't mind spending the money if you switch to Raylar heads you will gain a little bit of power but you will also save a lot of weight the same may be true for changing the exhaust but I don't know what the 07 manifolds and risers weigh. The weight savings alone could be good for another 2-3 mph.
I am concerned about doing any engine mods like CMI headrers, because I just have the Bravo drives which are only rated for 450 hp I believe.
Get out a long straight edge and confirm if this is true, if it is you will get more speed from a box. Buy pair of stellings boxes and you won't have to buy a shorty lower, it will put you up 2" and back about 12"
With 1/2 tank of gas I was able to get 96mph - I have a feeling, I'll gain another 1-2 mph once I consume more fuel and get down to about 1/4 tank.
Less weight = more speed no question. You should do your top speed testing on cold dry days with around 1/8 tank of fuel. As long as you can do it somewhere near a gas dock no more than 1/4. Take everything out of the boat you don't have to have by law and no passengers!
Some other interesting observations:
1. My port RPM's are about 200 higher than my starboard engine. So at WOT and trimmed up to about 3.5, my port engine will be running at 5100 while my starboard engine runs about 4900. I manually trim out the starboard, or trim in the port engine to try and synch them up, but I found this curious - any thoughts why this may be occurring?
Are the drives at the same level at 3.5 or are your indicators off? What kind of tachs do you have? Besides that i'm stumped
2. Boat pulls slightly to Port at certain speeds - I notice that I have to slightly continually steer to starboard while under way at certain speeds - what do you think explains this?
You're drives may be out of alingment or your tachs are reading incorrectly.
I've seen other posts where people seem to be consistently breaking the 100mph mark w/496's on 28's....what do I need to do to achieve similar results - wll standoff boxes help? What kind of gains would boxes provide?
See above, also if you don't mind spending the money if you switch to Raylar heads you will gain a little bit of power but you will also save a lot of weight the same may be true for changing the exhaust but I don't know what the 07 manifolds and risers weigh. The weight savings alone could be good for another 2-3 mph.
I am concerned about doing any engine mods like CMI headrers, because I just have the Bravo drives which are only rated for 450 hp I believe.
04-24-2007, 10:11 PM
#9
SeaRay Sundancer
Gold Member
Join Date: Nov 2005
Location: SW Missouri
Posts: 2,914
Likes: 0
Received 0 Likes
on
0 Posts
I wouldnt run 650 or 625 on a bravo of any type. But i think 500 is a safe number. IMO
04-24-2007, 10:52 PM
#10
Platinum Member
Platinum Member
The season has begun!
I took delivery of my '07 28 in Sept of last year that came w/stock 4 blade merc 32's. I have twin 496HO's (stock) with Bravo drives 1.36 gear ratio.
With the 4 blade props, I was able to squeeze 100mph out of it in ideal conditions - but depending upon load, it would run anywhere from 92-98 consistently.
The center of my prop appears to be about 1" lower than the bottom of my hull. No cavitation plates. No stand off boxes.
I started the season off on Sat, and put on 5 blade 30's.
The extremely obvious difference was the hole shot. With the 4 blade and full tanks of gas, it took some serious finess to get on plane...with the 5 blade - I am up on plane easily at around 2400 RPM's and fullt anks of gas with 5 guys in the boat....with the 4 blade, I would have to move people up front to get on plane with full tanks of gas.
With full tanks of gas, I was able to get 94mph with the 5 blade - 65 degree air temp, less than 1 foot of chop.
With 1/2 tank of gas I was able to get 96mph - I have a feeling, I'll gain another 1-2 mph once I consume more fuel and get down to about 1/4 tank.
Some other interesting observations:
1. My port RPM's are about 200 higher than my starboard engine. So at WOT and trimmed up to about 3.5, my port engine will be running at 5100 while my starboard engine runs about 4900. I manually trim out the starboard, or trim in the port engine to try and synch them up, but I found this curious - any thoughts why this may be occurring?
2. Boat pulls slightly to Port at certain speeds - I notice that I have to slightly continually steer to starboard while under way at certain speeds - what do you think explains this?
I've seen other posts where people seem to be consistently breaking the 100mph mark w/496's on 28's....what do I need to do to achieve similar results - wll standoff boxes help? What kind of gains would boxes provide?
I am concerned about doing any engine mods like CMI headrers, because I just have the Bravo drives which are only rated for 450 hp I believe.
I took delivery of my '07 28 in Sept of last year that came w/stock 4 blade merc 32's. I have twin 496HO's (stock) with Bravo drives 1.36 gear ratio.
With the 4 blade props, I was able to squeeze 100mph out of it in ideal conditions - but depending upon load, it would run anywhere from 92-98 consistently.
The center of my prop appears to be about 1" lower than the bottom of my hull. No cavitation plates. No stand off boxes.
I started the season off on Sat, and put on 5 blade 30's.
The extremely obvious difference was the hole shot. With the 4 blade and full tanks of gas, it took some serious finess to get on plane...with the 5 blade - I am up on plane easily at around 2400 RPM's and fullt anks of gas with 5 guys in the boat....with the 4 blade, I would have to move people up front to get on plane with full tanks of gas.
With full tanks of gas, I was able to get 94mph with the 5 blade - 65 degree air temp, less than 1 foot of chop.
With 1/2 tank of gas I was able to get 96mph - I have a feeling, I'll gain another 1-2 mph once I consume more fuel and get down to about 1/4 tank.
Some other interesting observations:
1. My port RPM's are about 200 higher than my starboard engine. So at WOT and trimmed up to about 3.5, my port engine will be running at 5100 while my starboard engine runs about 4900. I manually trim out the starboard, or trim in the port engine to try and synch them up, but I found this curious - any thoughts why this may be occurring?
2. Boat pulls slightly to Port at certain speeds - I notice that I have to slightly continually steer to starboard while under way at certain speeds - what do you think explains this?
I've seen other posts where people seem to be consistently breaking the 100mph mark w/496's on 28's....what do I need to do to achieve similar results - wll standoff boxes help? What kind of gains would boxes provide?
I am concerned about doing any engine mods like CMI headrers, because I just have the Bravo drives which are only rated for 450 hp I believe.
