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A twin turbocharged inline-4 diesel engine producing 204 horsepower? Sounds familiar but we are not taking another look at the engine powering the BMW 123d again here, instead this is Mercedes-Benz’s new OM651 turbodiesel engine, which is available in 3 stages of tune.
In the 250 CDI state of tune, the 2,143cc turbodiesel produces 204 horsepower at 4,200rpm and 500Nm of torque between 1,600rpm and 1,800rpm. Two lower states of tune are available – a 220 CDI tuning which results in 170 horsepower between 3,200rpm and 4,800rpm and 400Nm of torque between 1,400rpm and 2,800rpm, and another 200 CDI tuning produces 136 horses between 3,000 and 4,600rpm, and 330Nm of torque between 1,600rpm and 2,800rpm. Installed in the W204 C-Class, the 204 horsepower engine pushes it up to 100km/h in a mere 7.7 seconds, with 60 to 120km/h taking 9.4 seconds.
The twin turbochargers are installed in a sequential manner, with one high pressure small turbocharger spooling up quickly for low revs and the other low pressure large turbocharger taking care of the higher engine speeds. The high pressure turbo that serves the low revs has a bypass duct to prevent it from being overloaded, and it ceases work from medium engine speeds onwards.
The engine also has a fourth generation common rail system with 2,000 bar rail pressure, a big up from the previous generation 400 bar pressure. Maximum ignition pressure is 200 bar, and injectors are piezoelectric.
For smoother operation, two Lanchester balancer shafts with low-friction roller bearings help counter the vibration inherent with inline-4 designs. The engine’s forged crankshaft also has eight counterweights turns supported by five bearings. Conrods are made of forged steel, with weight optimised by Mercedes-Benz engineers. The aluminium pistons slide up and down in cast-iron barrels for minimum frictional resistance.
Lastly, the engine uses a two-mass flywheel which connects a primary flywheel to a secondary one by use of springs to isolate the crankshaft’s vibration from the drivetrain.
You will find a power and torque curve after the jump.
Related Posts:
BMW announces 204 horsepower 400Nm twin turbodiesel inline-4
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Very concised and informative report. Well done Paul!
Well done M-B as well :)
Pity the diesel quality (or rather the lack of) that we have here in Bolehland :(
Paul,
“The twin turbochargers are installed in a sequential manner, with one HIGH PRESSURE small turbocharger spooling up quickly for LOW REVs and the OTHER low pressure large turbocharger taking care of the higher engine speeds. The LOW PRESSURE turbo has a bypass duct to prevent it from being overloaded, and it ceases work from MEDIUM engine speeds onwards.”
Is it just me or the above paragraph indeed doesn’t sounds right. One contradict each other.
Paul Tan says: yeah you’re right, its the high pressure low rev turbo that stops work from medium revs onwards, corrected already
mouthwatering! 500Nm from a 2134cc engine! impressive!!!
MyBoy said,
April 11, 2008 @ 12:58 pm
Is it just me or the above paragraph indeed doesn’t sounds right. One contradict each other.
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Naaah Paul’s description is quite clear my boy.
wah… when will this GEM find it’s way into a ssangyong?
High pressure turbo spooling Low Rev
Low pressure turbo spooling High Rev (Bypass valve to avoid overload and ceases at medium revs)
I think that’s what Paul is saying.
Myvikiller,
u should read carefully… even Paul admit he has make the mistake.. & corrected it
awsome!! think what it can do if that diesel engine put in pick-up truck like ranger, hilux, triton …sure can beat normal passanger car at traffic light!
This is one expensive engine! with complex turbo boost control and torque control. What impresses me is that Mercs didn’t try to save money on it. Instead, it comes with full on balancer shafts and forge pistons.
I bet if you can free up the computer limit of this engine. It can probably do another 550Nm or 600Nm of torque. Enough to wreck your gearbox or smoke lots of tyres.
in kk,already tried in a vigo and land cruser 1hz.(4,2 litre diesel).beutiful set up,never ending power,(15psi).on a vigo,not fully utilise due to chip parameters,(not enough fuel)DP chip cannot supply enough fuel.(setting at no.9),land cruiser good power enough fuel,howver inlet charge too hot so charge cooler currently being fabricated.i have a rexton rx290,this will have the set up some time this year.doing alot of research in fueling,finnish people manged to squeeze out 295bhp on a korando,
http://www.ssangyongclub.co.uk/forum/index.php?showtopic=152&hl=diesel%20tuning&st=40
this turbo set up is the same on the bmw,opel,saab.peogeot has a slightly different setup(similar to petrol type),Q,,can this be done to all 2.5 turbo diesel sold in malysia? CAN.fuelling is the only issue for common rail type but on mechanical type fuel pump there is hugh potential.my curent project is a supercharged turbocharged isuzu.you can read about it here.
http://clubisuzu.proboards29.com/index.cgi?board=Enginemods&action=display&thread=1020
dis engine does not have a leak off line at the injector, but why do they have the timing at the rear of the engine
Old article but I bought a MY12 C250 CDI with the OM651 engine and recently dyno’d it to yield 147.1kW at the wheel; but even more impressive, a torque curve which was above the 600Nm mark for a good amount of range before trailing off.
Hi,
I just ask about how much torque to tightening the bolts of the engine Mercedes Benz OM651 Diesel 2.1, 4 cylinders, I need to know how much torque when using the tension wrench when fixing and fitting the parts inside the engine.
Thanks