Well, its kinda ironic. psfred, you had it partly right. Work done (power out) = force X distance. Or in this case mean effective combustion pressure X stroke. But this is an arguement for the longer stroke you don't like and also explains why compressing fuel / air past the point needed for ignition leads to a loss.

Benz and Volvo both make high compression engines with short strokes. Higher compression give more expansion and hence more useful energy and less fuel consumption per unit of fuel burned, so more power per unit of volume.

This is plain thermodynamics, has nothing to do with design philosophy.


Peter

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1972 220D ?? miles
1988 300E 200,012
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psfred

I agree with you that many American Diesels are set up to emulate stationary engine setups, but this is pretty much exactly what an over the road diesel truck engine is. It should be designed to run in a narrow RPM band and perform in a fuel efficient manner when operated in the "sweet spot"

I'm perplexed by your assertion that American Diesels are not efficient. My 7,000 lb Dodge/Cummins 4X4 pickup truck will return an honest 21-22 MPG running empty and 16-17 MPG towing a loaded car trailer. These figures compare pretty favorably to say an 87 W124 Diesel sedan that might get 30-31 MPG.

I don't have BSFC figures for am OM603 but I would bet they would not be significantly better than a Cummins B.

Tim

psfred,
I didn't say that rpm was bad just that a low torque peak makes it much easier to drive a tow vehicle especially when its loaded down. My experience towing with gassers and their higher torque peaks and higher revs has made this pretty obvious to me. I am also pretty sure that the IP in my old tech 6.5GM has a mechanical advance system so the timing is not fixed. These pumps have been around for years. My old tech IDI engine also manages 20-21mpg cruising at 70-75mph, 14-15mpg pulling 5-6K. Not too bad for a 6K brick IMHO. Additionally it redlines at 3600rpm but I have never needed to spin it that fast as it gets the job done fine at lower rpm. Oh yeah, AFAIK the new dmax/ps will spin to 4K no problem. I just don't get your rpm fetish. If low revs do the job, what is the advantage in higher rpm? RT

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The 270 CDI is a 5 cylinder engine. If you could get a CR system out of a wrecked one you are almost there

I sure would like to know how things worked out if you could adapt this into a older pre chamber engine.

BTW I think if you're chipping a new 220 CDI engine it gives around 175 hp / 360 Nm torque

And the 320 CDI will give 234 hp / 555 Nm if chipped.

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1999 E-220 CDI (W210-T) Wagon

There are so many posts here that I don't have time to read them all so I hope I'm not repeating. If you remove the prechambers it won't even run. The reason tractor trailer rigs have been able to run direct injection is because of the relatively low rpms they turn. Car engines need prechambers to allow combustion at higher engine speeds. The new TDIs have pistons that have been totally been reshaped to act like a prechamber. If you saw the top of a TDI piston you wouldn't believe how radical it is.

Peter

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*Dreaming* I wonder what the V10 TDI can put out chipped...

I'll tell ya.

Original it is 313 hp / 750 Nm
Chipped it is 370 hp / 820 Nm

This is out of the KCR Racing webpage which you can find HERE

A shame they don't have a english version, but you basically find your brand of car where it says "sok ditt merke her" ,and then you click "visa" Which by the way does not mean the credit card, but "show"

You can also try THIS LINK

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1999 E-220 CDI (W210-T) Wagon

Back to the original question. IF you want more power from an MB turbo diesel, add an intercooler and turn up the boost & fuel as much as the EGT's allow. Forget propane. Forget touching the injectors, prechambers, etc. Porting the head is great but expensive and time consuming. The intercooler is mostly a bolt-on, but will require internal IP tweaking to increase fuel delivery - you can NOT just turn up the ALDA and expect top-end power gains! Mosselman Turbo gets 20% power gain and 25% torque gain on their 602/603 intercooler kits, and I'd expect you could get at least that with a decent intercooled 617.

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Hello. I am new to this forum. My name is Bogdan ANCA and I am from Timisoara, Romania. I own a w123 240D and a w123 300TD. (just to let you know what i am interested in )

I thought a while on removing the precombustion chamber, but that is a bad ideea, because the whole force distribution inside the cylinder is calculated with the combustion chamber on. So like many posts in this thread warned about it is very probable that something will break if it is removed.

But the idea remains, kinda...
What if we throw away the injection pump which is mechanical (and we all know how hard is to set it right) and replace the injection system with a common rail, computer controlled, so the timing of the injection will be almost ideal regardless of the temperature outside or the load of the car or other factors? wouldn't that be a great thing for the engine? (and the driver?)

It sure would if you had a couple million $ to spend on research and development.

It would be FAR cheaper to buy a new crate CDI engine and transmission from Mercedes and fit it to your car.

LOL, it would be far cheaper to buy a whole fleet of new CDI cars.

HEHE, lol.
Actually I am an computer science graduate, major in embedded systems. I did a project like this but for a gasoline engine, (a Dacia 1300 which is a copy of Renault 12), and it is running very smooth, not to mention the fuel economy . (as an inspiration I took the Megasquirt system, but used a totally different approach. But they have a very good theoretical starting point).
Sure, a gasoline engine is far more easy to control than a diesel. But I don't see why it should take that much money. All you need to buy is a couple of new electric controlled injectors (i.e. with solenoid) and to manufacture the common rail and pipes to the injector to your specifications (mine was made by a company specialized on high pressure pipes). That was the expensive part of the project. It was about 700 euros, which is abot 1200 US$. You also need some mass air sensor,throttle position sensor, air temperature sensor, manifold absolute presure sensor, and lambda sensor, and I manufactured myself a crackshaft and camshaft position sensor (using laser diodes and phototransistors and a disc with holes in it). (I don't know why even today, the cars use hall-effect sensors for that ). A ping (knock) sensor is a nice touch also.

You just have to figure out what are the timings for the injections and how to calculate the amount being injected. And that is not very hard, being a mechanical system this can be done even with reverse engineering, but I am sure that there is some documentation on this somewhere.
The only problem in my mind is what pressure should the common rail have? (for the gasoline engine i used 3.5 atmospheres).
The timing on the w123 engine I think is 24 degrees, so that's solved. the next thing is to find out what is the relation between the throttle position, manifold pressure (and other variables, i don't know the w123 engine that well, but I am keen to find out the whys and hows) and the amount of diesel injected. I don't think that's hard to do also.

As we are on the subject. My new w123 300TD was a taxi before I bought it (last week ), and makes horrible horrible noise compared to the 240D my father uses. The pistons are ok, not broken or anything (the former owner did the segments at a garrage, and i peeked to see what's inside the engine). Do you think that valve adjustment and injector nozzle replacement will help? I also read an article on the internet that the precombustion chamber can be cleaned too.. Do you know how that is done?
Thank you

Converting an IDI engine to DI is not (reasonably) possible and the mechanical system works very well as-is so there is really no point in going common-rail.

Economy is mostly factors of engine efficiency and your right foot. The CDI's are far more efficient than a 617 and you can already get 30-32mpg out of a 617 in proper tune with mechanical injection if you drive smart.

Software = cheap

Hardware = expensive