Tamd41 low turbo psi. Boat gets WOT, no smoke??

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jw_2000_uk

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Hi. Story so far.

New boat. Sorted other bits,

Turbo compresser wheel needed replacing, so of it went for a full refurb.

Engine makes 3950+ without hesitation.

Temps 82c,oil psi 75psi all spot on.new exhaust riser

But it wont boost over 15psi should be 21psi, it fluctuates down also. Checked gauge, checked all over for boost leaks today, only leak is from intercooler weep hole. Standerd i thought.

I have sent the turbo back as i thought it was the turbo. Its returned rebuilt again. And no improvement.

It also makes a high pitch noise from 2500+

And a rattle noise at low rpm.

There a huge company. Surely its not been rebuilt incorrectly twice lol.

But i cant see what else it could be.

Lack of fuel?? But would it then perform so well reaching wot + 100rpm

Video of noise
 
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Can't see any problem here apart from the readings! You're getting max rpm, even if it was at lower boost (Which is unlikely) so the engine is giving you the full beans... :-D
 
Checked gauge with a mechanical gauge. Its spot on.

Been on the phone to company, it could be surging. So ive got some tests to do on turbo.

I could just use it as is, but i prefer to have everything correct .

Plus lower boost means higher EGT.
 
Can't see any problem here. Assuming its an MF805 it should do 20/21kts sog in flat calm water and lightly loaded, any extra weight and waves will knock this down a bit. Looks from wash that it's doing fine for a stable platform semi dispacement. Engine sounds good so I wouldn't be worrying. The TAMD41P is the last of a long run of well tried and tested lumps that could be worked on without laptop diagnostic software and preferable imo to the later and cheaper 4 cylinder Nannis fitted as standard. You may be overthinking things a little which is often the case with a new boat.
 
dash300 said:
Can't see any problem here. Assuming its an MF805 it should do 20/21kts sog in flat calm water and lightly loaded, any extra weight and waves will knock this down a bit. Looks from wash that it's doing fine for a stable platform semi dispacement. Engine sounds good so I wouldn't be worrying. The TAMD41P is the last of a long run of well tried and tested lumps that could be worked on without laptop diagnostic software and preferable imo to the later and cheaper 4 cylinder Nannis fitted as standard. You may be overthinking things a little which is often the case with a new boat.
Click to expand...

It does all as you say mate. And without a high squeel noise id be cleaning it all up, and shutting the hatch for summer.

But something definitely isnt 100%. I could probably live with the psi loss, but the noise is definitely a concern.
 
jw_2000_uk said:
Hi. Story so far.

New boat. Sorted other bits,

Turbo compresser wheel needed replacing, so of it went for a full refurb.

Engine makes 3950+ without hesitation.

Temps 82c,oil psi 75psi all spot on.new exhaust riser

But it wont boost over 15psi should be 21psi, it fluctuates down also. Checked gauge, checked all over for boost leaks today, only leak is from intercooler weep hole. Standerd i thought.

I have sent the turbo back as i thought it was the turbo. Its returned rebuilt again. And no improvement.

It also makes a high pitch noise from 2500+

And a rattle noise at low rpm.

There a huge company. Surely its not been rebuilt incorrectly twice lol.

But i cant see what else it could be.

Lack of fuel?? But would it then perform so well reaching wot + 100rpm

Video of noise
Click to expand...

I have the same engine, just over 1000hours, like yours i also have spot on revs and boat speed at wot underway and about the same amount of smoke as yours. However, i do not have a boost gauge so have nothing to worry about......

Www.solocoastalsailing.co.uk
 
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The noise from the video clip doesn't sound right to me and I think you're right to be concerned. It's hard to diagnose remotely.

It's not surge. The Compressor stage surges when it develops high pressure at low flow and finds itself in an unstable region of its operating range. The most common example is a gasoline engine. Hard acceleration, foot off pedal to change gear, throttle closes so no flow but still high pressure. Compressor stage becomes unstable and surges. No doubt you've heard the noise as a boy racer accelerates away from the traffic lights. A diesel doesn't have a throttle body. During diesel engine development, the turbo turbine housing is sized to avoid compressor surge at one extreme of power/load curve and choke at the other. Unless its the wrong unit, it would be impossible to make the compressor surge at higher engine speeds and loads
 
Sounds like compressed air to me and the air route from the turbo to the block is not that complicated. Best guess is the pipe attaching to the turbo, if that don't have the right o-ring or is off angle I think it would leak a bit.
If its compressed air you should be able to feel it if you feel around the pipes from the turbo to the intercooler.
 
Must admit, sounds perfectly normal to me.
If it's surging on a known calibrated gauge, it likely has a momentary leak at full boost, then re sealing again at a certain lower pressure.
I'd be tempted not to worry about it if all else seems good.
If you are worried about it, my next step would be to run it on full load as in video with someone at helm and another holding an a4 clean piece of paper next to the all the obvious HP side of turbo, likely sources of leakage.
But....doesn't really sound like it's obviously leaking.
 
Is the boost pressure being measured before or after the aftercooler. I would expect you are measuring it at the inlet manifold so a blockage in the aftercooler would give you low boost. Was the body of the turbo replaced (exhaust side)? The turbos normally suffer from the exhaust housing corroding away and leaving a bigger gap between the housing and the turbine blades. Automotive turbo overhaul places won't know about this. With a worn housing you still get max rpm but it looses acceleration.
 
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