Guys, out of curiosity, what's the max boost this engine will take without going to head studs or copper head gaskets or other exotic parts?

Thanks!

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Far more than what the stock KKK K14 could ever push out.

What about in theory? Stock turbo aside... 40PSI? What's the compression ratio? Thanks!

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

I know one finnish guy boosted 2.5+bar with his holset hx40 on a stock engine. Wonder what they do with the fuel pump to keep the a/f ratio in place. anyways he dyno-ed 430hp @ 2.2bar of boost. Pretty cool for diesel eh?

The great thing about diesels is you don't have to worry about the air/fuel ratio so long as you don't put so much fuel in that you hydraulic the cylinders.



too much fuel for amount of air = smoke.

not enough fuel for amount of air = higher efficiency

__________________
green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday )( Kalifornistani emissons )
white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank)
desert storm primer 63 T-bird "The Undead" (long term hibernation)

http://ecomodder.com/forum/fe-graphs/sig692a.png

yea, but you have to be "in shape" at least a/f ratio has to been more or less ok otherwise you dont get the desired power. I mean, only air won´t generate power.
So basically you turn boost, add fuel step by step? or how do they do it on diesel engines?

Hmmmm, 2.5 bar is a little less than 40 PSI.

With a Diesel, only the fuel is metered to generate the desired power. Total engine output is mostly about how much fuel you can inject. The air is what supports combustion and keeps EGT's under control. The F/A ratio varies widely depending on the power the engine is putting out. At low loads, there is a surplus of air and the EGT remains low, sometimes around 250 deg. When the throttle is opened, more fuel is injected and more air ingested which balances out the mixture. If the throttle is stabbed open and fuel is applied quickly, that's when you get a puff of smoke as the mixture goes rich briefly then returns to normal indicated by the smoke clearing. In stock form, the injection pump is set so that even under a load, at full throttle, the EGT's won't exceed the safe level of 1270 or so deg. F.

A turbocharged engine works the same way, you can just increase the total fuel delivered because it packs more air into the engine to keep peak EGT's at acceptable levels. When you see a Diesel pouring smoke, the EGT's are on their way up and generally this condition can't be sustained indefinately because of the posibility of damage to the engine.

In a nutshell, Diesel performance is all about volume of fuel, proper atomization and enough air to keep EGT's at bay. It's just the reverse of a gas engine. Lean is cool and rich runs hot. You also may not realize that most Diesels don't have a throttle plate. It's open to the air all the time.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

nice, that educated me pretty much. So I have to think how to get more fuel to the engine and after that more air. But what hapens if we are useing a huge turbo @ 35psi with stock fuel injection? we dont gain power? what hapens to the EGT?
Yep I know that diesels dont have throttle plate, thats why they need external vacum pumps.

What do you mean "proper atomization" ?

In general, a bigger turbo may not always equal more boost. If it's too huge in fact, the engine may not generate enough heat/drive pressure to spin it effectively. Even if it's sized properly to deliver the desired boost at high loads and those levels fall within the effeciency range of it's compressor map, it'll probably end up with quite a bit of lag.

Early on and today as well, manufacturers use a turbo that is a compromise between early light off and top end boost so it generates desirable performance with a minimum of lag. Now days you have the option of VGT's which use a variety of methods to vary the "displacement" of the turbo so it performs effectively throughout the RPM range. Ball bearings can also permit a larger turbo to be used because they spool up and generate boost faster. Another choice is a hybrid turbo that uses a smaller turbine section driving a larger compressor. Really high boost levels require compounding to reduce the heat introduced into the intake charge.

Now to atomization. It is simply the quality of the fuel spray from the injector. This is critical on any engine, gas or Diesel. It can be effected by a number of things including available fuel pressure and contamination of the injector tip. Poor atomization results in poor combustion, over-rich mixtures, high EGT's and contributes to black smoke. On mechanically injected ingines, you generally don't have to worry about this except that if you install hotter, high flow injectors, you have to make sure that the injection pump is up to the task of supplying them. Hot rod CRD's and HUEI engines have similar problems. Hypo CRD's can suffer from low fuel pressure and poor atomization from aggressive programs that seek to introduce more fuel than the pump can supply. The common solution is to install a second pump. HUEI's can suffer low fuel injection pressure because bigger, oil hungry injectors and programs will run the oil system out of pressure, reducing the drive available to the injectors.

So, here's some basic Diesel hot rodding:

1. Improve breathing - install low resctiction exhaust and intakes.
2. Increase total fuel injected - turn up pump on mech. engines, chips or programmers on computer controlled engines.
3. Increase available boost - adjust or modify wastegate. Don't push turbo out of it's effeciency range as it will introduce an unacceptable amount of heat. Turbo bearings and seals can also be damaged by too much boost.

Some alternatives are: Bigger injectors, different turbo, bigger pumps, VGT's, compound twins, etc...

Hope it helps.

Oh, almost forgot, don't horse around with your fuel/boost without FIRST installing an EGT gauge!

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

I am totally aware of the turbo effency part and allmost everything that includes petrol engines, but now planning to build my own diesel power plant.

Now, to be exact. i have a 3.0 inline 6 merc turbocharged diesel engine from w124.
What do you recommend to do with the fueling? I had an idea to install w140 3.5td injectors (should be bigger?). Some finnish guys once spoke something about drilling the "elements" in the pump. they sayd that from stock they are 5millimeters and you have to drill them 8 millimeter. Have you got any idea what they could think of?

About the breathing.
I tought about installing a big intercooler, holset turbo, custom exhaust mani, custom intake, custom exhaust all the way 3". Some porting, portmaching should allso be done.

I use metric because I am european and dont know much about your scales, sorry.
All advice about the fueling solutions is very welcom.

Allar

First, set your HP goal and then determine what mods will take you there. It sounds like you're on the right track with the intake and exhaust mods. For fueling, find out if the engine is electronically controlled or mechanical to determine the correct mods. I'm very new to Mercedes so I can't quote specific parts. My background is more Diesel trucks.

For a turbo, you may also consider a VGT. Many guys have good luck adapting them.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

first, I would like to make something like that http://www.cardomain.com/ride/2275926

it has 313kw (430hp) @ 2.3bar of boost.

Bottom end is stock only mods are fueling and breathing.

This type of mercedes engine uses a bullet-proof (eats everything) fuel pump. Its not rotary but I dont know how to call it in english.

Why I choosed holset turbo, is that I basically have it on the shelf (proper size to use on 3.0 diesel) so no need to buy new one.

but again what to do with the pump?

EDIT: that merc eingine uses mechanical pump so no "brains" out there.
Newer ones have electronically controlled pumps.

I have the same question. Is it possible to dynamically control the injection pump on an OM603 turbo?

__________________
Doug

1987 300TD x 3
2005 E320CDI

We're talking about the OM603, here....Not the OM606, right? The car pictured on that site has a modified OM603, not a OM606.

__________________
1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)

doesent matter @ the moment, cause they both use the same pump. So the anybody? How to increase fuel flow rate from pump?