sunseeker Mustique

Overload will happen if throttle setting does not correspond with achieved RPM ... when you brought the boat onto plane did you push her to 1800 RPM and stop there .... or did you let her run over .. let's say above 2000 RPM and then throttle back ? .... you cannot "feel" that the engine is strong ... the engine need to operate within its performance envelope...

It could be that you cannot achieve more than 1800 RPM ... which mean that you try to fuel for 2300 RPM, but only can achieve 1800 RPM on the engine ... that will be classed as overload and may be caused by fouling on hull, too big propellers etc., etc..

Personally, I always push our DD's over the 2000 RPM mark (to see her rising above) and then throttle back to 1800 - 1850 RPM for cruise as I then know that I am well below full throttle (full fuel) setting and that I am at less risk overloading the engine(s)..
 
Divemaster1 said:
Overload will happen if throttle setting does not correspond with achieved RPM ... when you brought the boat onto plane did you push her to 1800 RPM and stop there .... or did you let her run over .. let's say above 2000 RPM and then throttle back ? .... you cannot "feel" that the engine is strong ... the engine need to operate within its performance envelope...

It could be that you cannot achieve more than 1800 RPM ... which mean that you try to fuel for 2300 RPM, but only can achieve 1800 RPM on the engine ... that will be classed as overload and may be caused by fouling on hull, too big propellers etc., etc..

Personally, I always push our DD's over the 2000 RPM mark (to see her rising above) and then throttle back to 1800 - 1850 RPM for cruise as I then know that I am well below full throttle (full fuel) setting and that I am at less risk overloading the engine(s)..
Click to expand...
Hi bud
Yes I just eased her 20 1800ish and kept it there
Divemaster1 said:
Overload will happen if throttle setting does not correspond with achieved RPM ... when you brought the boat onto plane did you push her to 1800 RPM and stop there .... or did you let her run over .. let's say above 2000 RPM and then throttle back ? .... you cannot "feel" that the engine is strong ... the engine need to operate within its performance envelope...

It could be that you cannot achieve more than 1800 RPM ... which mean that you try to fuel for 2300 RPM, but only can achieve 1800 RPM on the engine ... that will be classed as overload and may be caused by fouling on hull, too big propellers etc., etc..

Personally, I always push our DD's over the 2000 RPM mark (to see her rising above) and then throttle back to 1800 - 1850 RPM for cruise as I then know that I am well below full throttle (full fuel) setting and that I am at less risk overloading the engine(s)..
Click to expand...
Hi bud
I just eased her to 1800ish Was in plane trim tabs down say an inch or so
I did momentarily go to 2000 rpm then eased Back to 1800
Didnt go above that
I could go to 2k rpm quite easily
Should top out at about 2200 -2300 max so I understand
 
Hu
Maritimeman1664 said:
Hi bud
Yes I just eased her 20 1800ish and kept it there

Hi bud
I just eased her to 1800ish Was in plane trim tabs down say an inch or so
I did momentarily go to 2000 rpm then eased Back to 1800
Didnt go above that
I could go to 2k rpm quite easily
Should top out at about 2200 -2300 max so I understand
Click to expand...
Hull was cleaned about 3 -4 weeks ago looks pretty clean
I believe the original bronze props are on her
Maybe a tune up from Charlie at Detroit UK
 
Your DDEC displays should be able of displaying "engine load" in percentage ... e.g. 75% ... that will tell you that you are fuelling at 75% of full load at the current RPM.... if you can get 2300 RPM at 100% ...
Also do you have EGT (Exhaust Gas Temperature) sensors / displays ?? If you have, that would be the first place where overload would be noticed ... if you do not have these, and plan to have the engines serviced (and tuned up), I would consider having a set installed by same professional ..
 
Maritimeman1664 said:
Had the hull scrubbed before we tested her on test So no probs there with cooling from Eastbourne to Cowes was consistent on the hour, as was oil temps
No black exhaust smoke and a real nice steady on plane all the way back just under 4bar pressure at 1500 rpm and 16kts
Had to replace a couple of batteries port side was down
All good now
Click to expand...
sorry missed the thread back in June, congrats and enjoy!
just curious though, do these DD go up to 4bar boost???
seems a bit much, no?
 
Divemaster1 said:
Your DDEC displays should be able of displaying "engine load" in percentage ... e.g. 75% ... that will tell you that you are fuelling at 75% of full load at the current RPM.... if you can get 2300 RPM at 100% ...
Also do you have EGT (Exhaust Gas Temperature) sensors / displays ?? If you have, that would be the first place where overload would be noticed ... if you do not have these, and plan to have the engines serviced (and tuned up), I would consider having a set installed by same professional ..
Click to expand...
Divemaster1 said:
Your DDEC displays should be able of displaying "engine load" in percentage ... e.g. 75% ... that will tell you that you are fuelling at 75% of full load at the current RPM.... if you can get 2300 RPM at 100% ...
Also do you have EGT (Exhaust Gas Temperature) sensors / displays ?? If you have, that would be the first place where overload would be noticed ... if you do not have these, and plan to have the engines serviced (and tuned up), I would consider having a set installed by same professional ..
Click to expand...
I’ll see if I can get that info up on the screens within the menu
If not I’ll chat also to Charlie at Detroit uk
And see if he recommends a tune / service I have the Detriot manuals so I’ll have a look see there
I understand it could be a lot of factors or combination so this info is invaluable thanks
 
Maritimeman1664 said:
Yesterday mine was showing just under 4bar of pressure
Click to expand...
Getting complicated now .... 4 Bar seems high ... seem to recall something of around high 20 lbs (around 28 ish) ... which is just below 2 bar .... then I also remembered how this stuff works ...
These DD's have a roots blower (compressor) and a Turbo ...
The larger DD turbo's had a bypass path (ie not through the blower like mine) ... "Boost Pressure" is measured on air resistance on the turbo side, so if forcing air through the blower, the "boost" (resistance) will be higher than if bypassing the blower.. so if high boost pressure and low performance, then it could be a bypass valve issue ... but as you do not smoke ... and appear to be getting the required RPM, then it probably will not be that being your issue ...
I would check engine spec for correct expected boost pressure ..
 
Divemaster1 said:
Getting complicated now .... 4 Bar seems high ... seem to recall something of around high 20 lbs (around 28 ish) ... which is just below 2 bar .... then I also remembered how this stuff works ...
These DD's have a roots blower (compressor) and a Turbo ...
The larger DD turbo's had a bypass path (ie not through the blower like mine) ... "Boost Pressure" is measured on air resistance on the turbo side, so if forcing air through the blower, the "boost" (resistance) will be higher than if bypassing the blower.. so if high boost pressure and low performance, then it could be a bypass valve issue ... but as you do not smoke ... and appear to be getting the required RPM, then it probably will not be that being your issue ...
I would check engine spec for correct expected boost pressure ..
Click to expand...
it was oil pressure on my gauges and DD dash
 
Maritimeman1664 said:
it was oil pressure on my gauges and DD dash
Click to expand...
:) ... thanks ...

General conditions for Turbo charged 92's

• Oil Temperature: Between 200-235 from 1200 to 2100 RPM. This is measured as the temperature in the oil pan. If you measure at the cylinder block, it will be slightly lower.
• Coolant Temperature: The normal coolant temperature is between 170-195 degrees Fahrenheit.
• Oil Pressure: Normal oil pressure (PSI) is 32-53 at 1200 RPM, 49-70 at 1800 RPM and 49-70 at 2100 RPM. The minimum pressure is 25 at 1200 RPM, 28 at 1800 RPM, 30 at 2100 RPM.
 
Heads up we’ll I was cleaning my boat today and noticed my trim tabs were right down ? I had my elbow on the tab buttons and had shifted them from the original position, no wonder she alarmed I’d knocked her off Plane whilst turning about so I guess the engine was trying to push her arse heavy through the water against the tide
Novice mistake I guess
I’m going to get a pair of trim tab buttons with led indicators so I don’t cock up again.
 
Maritimeman1664 said:
Heads up we’ll I was cleaning my boat today and noticed my trim tabs were right down ? I had my elbow on the tab buttons and had shifted them from the original position, no wonder she alarmed I’d knocked her off Plane whilst turning about so I guess the engine was trying to push her arse heavy through the water against the tide
Novice mistake I guess
I’m going to get a pair of trim tab buttons with led indicators so I don’t cock up again.
Click to expand...


KIS !!!! All the way down = Lift stern up !!

So you :

a) running on the edge of planning speed
b) made a too tight turn

Fix;

a) try running at 1850 - 1900 RPM (if you get full RPM at WOT) ... you may be surprised on how much lighter she'll run ... and how she becomes more agile...
b) do not take tight turns that drops her off the plane unless emergencies or intended..

No need for expensive fix....

Irrespective should not have led to overload for that short time...
 
Divemaster1 said:
KIS !!!! All the way down = Lift stern up !!

So you :

a) running on the edge of planning speed
b) made a too tight turn

Fix;

a) try running at 1850 - 1900 RPM (if you get full RPM at WOT) ... you may be surprised on how much lighter she'll run ... and how she becomes more agile...
b) do not take tight turns that drops her off the plane unless emergencies or intended..

No need for expensive fix....

Irrespective should not have led to overload for that short time...
Click to expand...
Good info
Thanks ?
 
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