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Discussion Starter #1 (Edited)
This is a thread for information known about the OM617 and performance predictions we can make based on that information.

Luckily for us the Mercedes OM617 is one of the better documented engines produced. From various published sources we have available the following information:
Performance curves showing power and torque throughout the rpm range.
BSFC Map which shows the engine efficiency throughout the whole operating range of speed and load.
Compressor map with operating regions overlaid which show the air consumption and boost pressure of the stock engine throughout the range of speed and load.
Plots of EGT and engine inlet temperature for full load across the rpm range.

From these I can crunch some numbers and come up with the following information.
Fuel Efficiency: The OM617 isn't a particularly efficient engine, it requires ~20% more fuel and air to produce power than a turbocharged direct injection engine. At the best point it requires ~250 grams of diesel per kilowatt hour for the OM617 vs ~200 g/kwh for the best direct injection engines. This is due to the indirect injection system losing a lot of combustion heat into the head and cooling system instead of heating and expanding air in the cylinder.
The most efficient stock operating point is around 1900-2600rpm and about 3/4 load. At this point it produces between 35 to 55kw of power (47-74hp).

Volumetric efficiency: This engine calculates out to using 80% of it's capacity at 1000rpm and drops to about 70% at 4000rpm. This is quite flat and shows no major drop-off with higher rpm.

Turbocharger efficiency: The TB03 turbocharger (48.6/59mm turbine wheel, 0.48 A/R housing) has a reported max boost of 10.3psi which should be reached from about 2500rpm onwards. The turbine maps out as a good fit for ~60% efficiency. This is 10-20% lower efficiency than better modern turbochargers. At ~1500rpm this engine/turbo combination should produce slightly more boost than drive pressure. But at 4000rpm max power the drive pressure will be around 16psi.

Fuel quantity: All signs point to stock injection quantities being around 47-50cc/1000 shots and pretty flat from ~1500rpm to 4000rpm.

Air consumption: The stock engine consumes about 0.12 kg/s of air at 4000rpm or about 15 lb/min.
 

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Discussion Starter #2 (Edited)
Better turbochargers: Now what will this engine do with a more modern turbocharger?

Fuel Limited: The first limitation is the injection pump. Analysing a few dyno plots from engines with stock but adjusted fuel pumps shows a limit is reached which corresponds to about 63cc/1000 shots of fuel. This is an increase of about 25% over stock.

Intercooling: A good front mount intercooler can remove about 80% of the heat from the boosted air. I have used this 80% in this calculation.

Max Air: Taking 63cc/1000 shots of fuel at an Air/fuel ratio of almost 20:1 (very clean and safe) at 4000rpm gives us a max required airflow of .17kg/s or 23 lb/min.

Max Boost: To fit that 23lb/min of air through the engine with a VE of 70% at 4000rpm and 80% intercooling requires about 18psi boost.

Suitable Turbines: Finding a compressor to fit is the easy part. The difficult part is chosing a suitable turbine. Too small can drive the compressor into surge and result in high drive pressures. Too big results in poor response and low boost/low torque at lower rpm.
I started by assuming a new turbine would have ~70% efficiency compared to the ~60% efficiency of the old TB03. I went straight to three possiblities. The HE221-6cm turbo (ISB4.5), the HE211-5cm turbo (ISF3.8) and the TD04HL-19T-6cm.
The HE221 turbine is about 7% smaller flow wise than the original TB03. The HE211 is about 30% smaller. The Td04HL-6cm is basically the same as the HE221-6cm.

The HE211 is too small and will both drive the compressor into surge and create excess drive pressure (~33psi drive for ~18psi boost). This is a result of the HE211 turbo being designed for an industrial engine which runs very lean (~27:1 A/F) and very cool EGT. So it has a turbine which is very small compared to the relatively large compressor for a 3.8L engine.
The HE221 is looking pretty good. The turbine kicks the compressor into life quite early and I expect around 10psi boost by 1500rpm (1000rpm earlier than stock). The drive pressure won't get higher than boost until about 2500rpm and drive pressure at 4000rpm will be about 7psi higher than boost.

Suitable Compressors: The interesting thing is the compressor side. While it picks up far enough away from the surge line, the air consumption only just makes it into the middle of the compressor map. So we can get better efficiency through most of the operating range by going smaller on the compressor.
Exactly how much smaller I haven't looked yet as there are many compressor maps availble in the MHI TD04 range. But here are the main requirements:
Surge: Must be okay at the point (PR=2.24, flow= 0.08m^3/s, 170CFM or 7lb/min).
Max Flow: Must be okay at the point (PR=2.24, flow= .15m^3/s, .173kg/s, 308CFM or 23 lb/min).

From these points there will be a selection of suitable compressors, you then choose the best fit based on efficiency and availability.

Expected Performance: Looks like all we can get from a stock pump (~63cc/1000shots) is around 300Nm and 110kw (220 ft-lbs and 150hp).
 

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This should be a sticky! Awesome information, thank you!
 

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This is great information. Second that on being a sticky
 

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I've been looking at different TD04 compressors, (Gurus, please correct me here if I'm wrong) it seems that the 19T is the only compressor that will not have surging issues on the low end. The surge line for the 15G, 16T, 17T, 18T is above our low values of PR=2.24, flow= 0.08m^3/s, 170CFM or 7lb/min. I'm hopefully picking up a He221w pretty cheap on Ebay tonight, but these TD04 units are super easy to pull from Volvos and Saabs I'd like to get a suitable one on hand also for testing purposes.

compressor_map.jpg
 

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Discussion Starter #6
I'll have a better look at the 15G later. It's gotta be close and may give better efficiency. The 19T will certainly work, but may not be ideal.
 

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I appreciate you sharing your knowledge and experience, I'll be interested to hear more regarding the 15G. For myself I'm mostly interested in improving the low end response of the engine with a faster spool if possible. I have no plans for larger elements, water injection, etc. In the future I may slightly adjust the pump, but very mildly as I'd like to keep everything cool and long lasting. So in this case it seems even a smaller compressor would be better as I don't plan on adding much extra fuel besides backing out the ALDA some more and perhaps slight torque control adjustment.
Again, thanks for posting!

EDIT, maps for 15G seems like the low end is just barely off, upper is just fine, probably worth a shot! Seems to be readily available with 6cm or 8.5cm turbine, I'll have to see which came stock on which cars I think Saab and Volvo, Volvo would be nice the turbine inlet flange easily adapts.
 

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The 15G map clears surge okay, but the best efficiency islands are too low so efficiency isn't any better than the 19T. There is a 15T wheel which I believe has a higher exit angle (should be more efficient at higher boost), but the chinese 15T compressor wheel I have is just a higher trim 13G.

May as well get the 19T and have the extra pressure and flow capacity for altitude work.

Regarding the ALDA. I don't think you'll need to adjust it much at all. A better turbo provides boost sooner and opens it sooner for more fuel to suit.
 

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Very good stuff here I too am looking for fast spool up on the low end up to about 4,000

archie
 

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Well, I bought a TD04HL-19T. I will run it first with no modifications and report back. Eventually I would like to mildly tune my MW pump and add an Air/Air intercooler I found one from a Saab 900 that will do nicely with a ram air duct. I think I found a ideal air intake for my swap as well - an air cleaner from a Euro w201 190D fits perfectly in the trucks stock cold air location, currenting trying to find flow rate data for it...
 

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Yes on the stock pump max adjustment is 62cc. That is all dieselmeken can get out of it anyway. He had a project to put so.e modified Renault elements into the mw but must have had some problems with it because he stopped doing that.

I think an underappreciated fact about these motors is how sensitive the head is to overheating. Many of these cars have been overheated over time and the heads are not rebuildable because the cracks are too big. So attention to cooling systems is important. Fortunately there are lots of old heads around, unless you have a wagon with an sls pump, in which case a rebuildable head is almost impossible to find anywhere on earth including from mercedes.
 

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My om617 with an adjusted stock injection pump, hx30 at 18psi, and W/A intercooler did 124hp at the rear wheels. And I adjusted the pump a little more after the dyno run and I know it runs better than it did when I dynoed, so I would say 150hp on a stock pump is spot on dougal.
Great math, great Info!
Thanks
 
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Dougal, when you say that there is more efficiency with the TD04HL-19 over the TD04HL-15, how much of a difference is there in the real world?

I can read the map that was posted previously, but I have a hard time translating the information into usable format for my engine. I am looking for a quicker spooling turbo for my CJ7, and don't run above 3750rmps very often at all.

Very curious to see how this thread progresses.
 

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Discussion Starter #14
Dougal, when you say that there is more efficiency with the TD04HL-19 over the TD04HL-15, how much of a difference is there in the real world?

I can read the map that was posted previously, but I have a hard time translating the information into usable format for my engine. I am looking for a quicker spooling turbo for my CJ7, and don't run above 3750rmps very often at all.

Very curious to see how this thread progresses.
From the 15T to the 19T you likely wouldn't even notice the difference driving at sealevel unless you're comparing known hills or acceleration times. The reasons to recommend the 19T are the better availability, better surge resistance and better fit on the compressor map.

18PSI is a PR of about 2.2. The 15G is most efficient at PR 1.6 and the 19T is most efficient at PR 2. So that's where the better fit comes in.
 

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Well guys, I've got my TD04-HL 19T installed. Initial thoughts are very positive. The turbo spools much quicker than stock, enough to left me shift 5 to 10 mph sooner without feeling like the engine is lugging. Work for this week is to an EMP gauge to determine drive pressure. Does anyone know of a good air cleaner that will silence as well as the stock unit? Turbo whine is awesome with my Fram CA8038 but it is not a cold air intake and the engine roar is very overwhelming. A Mercedes California version intake would be perfect but I can't find one anywhere!
 

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Part two of that is my drain tube setup is less than ideal, a 5/8 hose slipped over both stock drain tubes. Are there adapters to allow use of an AN hose or similar?
 

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Part two of that is my drain tube setup is less than ideal, a 5/8 hose slipped over both stock drain tubes. Are there adapters to allow use of an AN hose or similar?
There's not that much pressure in the drain tube. If the hose is oil resistant you should be fine.
 

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south,
I am getting boost sooner in the RPM range.

Once I get EGT and EMP (Exhaust Pressure) gauges installed, I'll be able to get some actual performance data. This is taking a while I'm also in the middle of swapping my 5 speed out for a 700R4 w/2000 rpm stall. I'm very excited about this new transmission. Combined with how much the new turbo improved drive-ability, I think this will be an excellent combo.
 
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