underpowered and frustrated

I don't think the 6.2L is considered a big block. I've heard it has more top end than the 5.7L, and about 320 hp. The big blocks, 7.4L and 8.1L, have more torque at the low end, and are 310hp and 375hp, respectively.
 
Alex F said:
..........You just lost your bet......
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Hey, I haven't lost yet. I said SOME 320 owners. Unless you're the Official Spokesperson of all 320 DA Owners Worldwide!
 
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I guess must mean you're not a 19-year-old!
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Nah, it just means I know enough to NOT enter a 3 legged horse in the Preakness!
 
The normally aspirated 5.7L makes 250HP, the Mag Horizon MPI makes 300HP and the 6.2L makes 320HP. They are all basically the same 350cubic inch GM engine.
 
I know what you mean. On Saturday I was on a friend's boat. At 3500 RPM we were getting just over 60 MPH. On the way back, he let her run to 4200 RPM and we were seeing speeds in the low 70s and the engines are rated to turn another 1500 RPM.

Then on Sunday we were on my boat. At 3500 RPM all I got was a lousy 26 knots.

But I know what I need to do. I just need to narrow the hull down to 8', increase the deadrise to 25 degrees, add steps, pad, notch the transom and drop 3,000 lbs. Then need to swap the engines for 800 hp Marine Innovation 677 cid big blocks, add Gil stainless dry headers and back them up with Arneson Surface Drives.

And a guy in the know said that it's a simple and cheap upgrade that I can do at home in my own garage.
 
billnpat said:
BOB, Please help me understand why SEARAY would put under propped props on one of there boats?? How does one know if he/she should should get biggger/more blades? props, if one is going to pay over 250 K on a boat he should have the right props, what am i missing???:huh:
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First, I asked if the OP had accurate tachometers because his rpm may indeed be within the acceptable range if the tachs are reading high. Second, he did not mention whether or not he factory props or not. If his tachometer was correct, he is outside the recommended WOT range for the 6.2L engine based upon what is on Mercruisers web site, what is stamped on my engine and what my prop shop told me of 4600-5000 rpm. The Mercruiser engine manuals that came with my boat had 4800-5200 as the WOT rpm range which was wrong. The Sea Ray 3 blade prop spec on their webside for a 2006 Sea Ray was LH 18x19 and RH 18x18.5. The MRIs that came from Mercruiser had both props as LH with 18x19 diameter and pitch. The prop book at Chicago Sea Ray had both props with the same pitch. When the damage props were removed, they had the different pitches but the RH prop had a different serial number than the MRI. So are you beginning to get the picture of how Sea Ray/Mercruiser could put the wrong props on a $250K boat?

Before I ran aground and tore up my props my WOT was in the mid 4500s for the port prop and mid 4600s for the starboard (smaller pitch) prop or at the bottom or below the spec. I have SmartCraft on my boat which my marina service manager says is almost alway spot on since it takes it readings from the engine computer. My props were toast so I worked with the prop shop to get a suitable 4 blade pro. Based upon the WOT data above they recommend going with a 18x18 4 blade prop. There rationale was to go with a smaller pitch to give me closer to the mid point of the range. They were unsure as to whether or not the starboard prop should have 1/2 inch less pitch but said try them out and they could adjust it down later. With new props, shafts, cutlass bearings, couplers and alignment the boat ran at 4841 port and 4714 starboard. I suspect something else was going on before I replace the underwater gear that was causing the port to run slower but I will never know since everything had been replaced. When the boat is pulled next week I will have them send the props back to the prop shop to have the pitch reduced on the starboard prop by 1/2" which they told me would increase the rpm by around 100 rpm.

So that is a long-winded explanation on how one knows whether or not they are over or underpropped. Hopefully this answered your question.
 
Four Suns said:
This is a f*cking joke... right?

Give me a break...

"Yeah... You should b!tch some more about that poor performance.. you are cool."

Did the "boating crowd" leave CSR? Are we just left with a bunch of 19 year old idiots now?
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Wow. Did it occur to you that the OP is not familiar with the typical performance of his boat/engine setup, and he sincerely believes he has a problem?

Maybe you should tell all of us exactly which posts deserve a response, and which ones should be ignored.
 
sea salt said:
I don't think so :smt018 you may want to find someone further "In The Know" for engine advise.
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My marina mate operates a marine transmission shop so he has some expertise in this area which is why I posted what he told me. If you have more knowledge in this area than he does, then I stand corrected.
 
Thank you Bob.....very good explanation....:thumbsup:
 
This thread started out as a complaint... the subject of "Underpowered and Frustrated" is a statement and not a question. Additionally this thread started after this thread:

http://clubsearay.com/forum/showthread.php?t=36292

Some guy complaining about performance of a newer 40' Sundancer because it won't go 40mph and then some dope head coming in and saying "Just run it WOT all the time."...

and then this thread pops up with a guy complaining because his Sundancer will only go 36 mph...

One has to wonder what kind of research or knowledge people obtain before buying a boat... Surely the operational envelope of a $100K+++ item is a basic thing someone would know before taking the boat out... or writing the check... maybe not...
 
320Bob said:
My marina mate operates a marine transmission shop so he has some expertise in this area which is why I posted what he told me. If you have more knowledge in this area than he does, then I stand corrected.
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You know that one of them runs in reverse, right? That is why they are pitched differently - they are geared differently. If you knew that, nevermind.
 
Hampton said:
You know that one of them runs in reverse, right? That is why they are pitched differently - they are geared differently. If you knew that, nevermind.
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Thats why i'm always playing with the sync gauge, if i see the port engine working harder then the starboard im always trying to center it.....but when there not centered i wonder why the boat still goes straight :huh:
 
Nope............The sync gauge is driven by the tach signal and has nothing to do with the prop rpms.

John's comment is relative only to some but not all ZF transmission where the design is such that the reverse gear has a slightly different final drive ratio than forward. The difference is minescule....like 2.48:1 one way and vs 2.476:1 the other and is easily handled by minor differences in prop pitch or cup between the port and stbd sides. You will never know there is a difference in the way the boat runs or handles and most people only find there is a difference when they have their props trued and balanced.
 
fwebster said:
Nope............The sync gauge is driven by the tach signal and has nothing to do with the prop rpms.

John's comment is relative only to some but not all ZF transmission where the design is such that the reverse gear has a slightly different final drive ratio than forward. The difference is minescule....like 2.48:1 one way and vs 2.476:1 the other and is easily handled by minor differences in prop pitch or cup between the port and stbd sides. You will never know there is a difference in the way the boat runs or handles and most people only find there is a difference when they have their props trued and balanced.
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Thanks Frank..
 
fc3 said:
But I know what I need to do. I just need to narrow the hull down to 8', increase the deadrise to 25 degrees, add steps, pad, notch the transom and drop 3,000 lbs. Then need to swap the engines for 800 hp Marine Innovation 677 cid big blocks, add Gil stainless dry headers and back them up with Arneson Surface Drives.

And a guy in the know said that it's a simple and cheap upgrade that I can do at home in my own garage.
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All you need to do is buy this boat. A good freind of mines latest venture. Only 3000HP and does 185mph.

http://www.youtube.com/watch?v=Wsc_qmnmKLw:thumbsup:
 
thanks Bob for actually understanding the question....the problem is not the top end speed but rather the poor responsiveness when I'm walking it around the marina. I'm looking into some bigger wheels right to gain some control. I've checked the tachs and they are correct. How are the 18x18 working out when you're moving it around.....ie. When you split the shifter sticks is there a long lag before you pivot?
 
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