Engine gurus!!!!!!!!!!
#21
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Z Zuperboat,i don't know how much power he'd need to spin 29's with 1.36 gears at 5400 but i do know that his boatwould be going 96 mph at 12% slip at thoses rpm's,i don't think his upgraded hp500's could do it w/o something that creates BOOST. Any 32 fountain non-step hull owners out there who have 700-800 hp who can post some speeds? I am impresed that he can go 80 at 4300,he is geared like you'd gear a tunnel cat boat,Smitty
#22
Ginger or Mary Ann?
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just a thought,
Since this is a twin engine boat, what is the likely hood of both motors having the same issue? From the picture of even RPM's and the lack of stating 1 motor is pulling more than the other, wouldn't it have to be a shared problem such as too high of props or fuel venting/delivery?
Also, since the cams are advanced an additional 2 degrees, will that make for better low end and less top end as his condition seems to be or vise versa?
Question...... can a restricted or insuffucient vent line still allow for acceptable fuel pressure until it sucks the walls in?
Since this is a twin engine boat, what is the likely hood of both motors having the same issue? From the picture of even RPM's and the lack of stating 1 motor is pulling more than the other, wouldn't it have to be a shared problem such as too high of props or fuel venting/delivery?
Also, since the cams are advanced an additional 2 degrees, will that make for better low end and less top end as his condition seems to be or vise versa?
Question...... can a restricted or insuffucient vent line still allow for acceptable fuel pressure until it sucks the walls in?
#23
Ginger or Mary Ann?
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Originally Posted by jryan26
I never ran it with the 500s. The previous owner said 80mph in salt water with 26p bravos. They are in a straight bottom 32' fountain.
#25
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I still think hes trying to climb a tall mountain with the 1.36 drives and prop selection,propped right he'll probably gain5-8 mph and be happy. Us1,don't you think if it was venting it would pull hard,die down then surge?
#26
Ginger or Mary Ann?
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Originally Posted by articfriends
I still think hes trying to climb a tall mountain with the 1.36 drives and prop selection,propped right he'll probably gain5-8 mph and be happy. Us1,don't you think if it was venting it would pull hard,die down then surge?
I don't know about the venting characteristic. Thus the question. Was just trying to throw some ideas in the fire and possibly help a brotha out.
jryan26
Mine are plain jane 502 MPI's
#27
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Smitty Could You Be A Pal And Figure Out My Slippage.im Running 79 With A 31 Pitch At 5200 Rpm With A 1.65 Gear.just Rerigged This Year With New Power And Drive Combo And Went Slower So The Props A Mercury Getting Some Rpm And Lift Put In.looks Like We Figured Out That Ryan Doesnt Have Motor Problems Just Not Enough Motor For The Drive And Prop Combo.
#28
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cam timing and prop(rpm) combinations make a HUGE difference! if someone installed the cams, 'straight up', without checking it (multiple lobes) or setting it for your application??...your asking for problems before you start.
so many start adding HP, or so they think, and never get what they expect.
also...if your bottom and or x-dim is not conducive to running any more speed??...a ton of HP will get you nowhere....being that this is an older boat, it was NOT setup to take advantage of todays propeller technology. you need to assess everything as a system and from there adjust or modify the components...not the other way around. good luck bro....let us know.
so many start adding HP, or so they think, and never get what they expect.
also...if your bottom and or x-dim is not conducive to running any more speed??...a ton of HP will get you nowhere....being that this is an older boat, it was NOT setup to take advantage of todays propeller technology. you need to assess everything as a system and from there adjust or modify the components...not the other way around. good luck bro....let us know.
#29
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Originally Posted by z.zuperboat
Smitty Could You Be A Pal And Figure Out My Slippage.im Running 79 With A 31 Pitch At 5200 Rpm With A 1.65 Gear.just Rerigged This Year With New Power And Drive Combo And Went Slower So The Props A Mercury Getting Some Rpm And Lift Put In.looks Like We Figured Out That Ryan Doesnt Have Motor Problems Just Not Enough Motor For The Drive And Prop Combo.
14.6094 %...........
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#30
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Ok 14.6% Is That Good For A V Bottom.i Know The Boat Laying Down Now And With Some Lift It Will Get Better But Whats A Good # For A V Bottom.