It is not my intention to jump in here, but on the subject of degrees of injection for a given element travel, I have tried raising the barrels on a NA 616 MW, in an effort to use a portion of the IP cam that is further from the cam center. My goal was to increase the element travel while maintaining the same degrees of IP cam rotation.

As foundation for this experiment, I read in a 603 manual (I think), that one of the changes that they made for that year was to change the pre-delivery height. I think they decreased it, but I would have to find it again to be sure. Since my barrel/elements have over 200K I did not want to lower them because of a possible ridge that may have formed over time.

With only the EGT gauge as an indicator, I was able to retard the start of injection timing to 20* (or less) BTDC and have lower EGTs ( about 50* lower, with a slower rate of increase), and just about eliminate smoke where it would at the stock barrel height.

The first time I shimmed the barrels up .007" ea. The idle was smoother, and after playing with the timing was able to get it to pull stronger and rev higher.

I then added an additional .007" making each barrel .014" higher than stock. I again saw a EGT drop, but not as much as before. The engine seemed to run flat, as if not to have a identifiable power band, regardless of start of injection timing. Also I could hear it want to rattle when I spooled it up.

I then remove the shims to see if I noticed a difference with the barrels at the stock height. I really need to get an engine on a dyno, but my butt and ears say that the first set of .007" shims produced the best "sense" of power increase.

It is my thinking that by raising the barrel .014", I was using a faster part of the IP cam which was creating a spiky delivery signal to the injector, as apposed to using the bottom of the cam (stock) would create a gradual pressure signal (a pressure ramp-up curve).

I think cutting the collars on the delivery valves has a similar surge affect, as (with the collars cut) the delivery valve will close sooner, maintaining a higher residual line pressure, which would change the pressure ramp-up curve, for the next injection, to more of a surge or spike.

This theoretical pressure surge or spike could be causing the injector pintle to jump up instead of gradually opening, which could affect the atomization of the injected fuel, which could be why I was hearing a rattle when I put the fuel to it with the .014" shims.

As you have made elements, I am interested to what your thoughts are on the effect the rate of delivery, (the pressure curve) has on the atomization quality of the injected fuel. I am guessing that the Injectors are intended for a specific rate of pressure increase to operate properly. There for, when going to larger elements, would it be adventitious to try using a lower portion of the IP cam to create a smoother more gradual pressure increase?

Haven't done anything. For the third time, I'm asking what all/any of you have done, once you've reached the point where the IP can't be adjusted anymore.

__________________
1987 SDL. The best there ever was.

You say you've figured out a way to get more fuel in and out of the IP. Hence my question.

What have you done to get more fuel...?

Larger elements!


OM616:

Be careful!
The plunger position over cam rotation angle curve is important (starting from BDC measuring the plunger position after each let's say 5 deg turn of the IP cam shaft).
I have to think about what you did in detail but the book says clearly that in any case the end of injection has to be just a little bit before the travel speed of the plunger is maximum.
Looking at this curve it is like a stretched "S" near the middle of the "S" you have the highest speed of the plunger. This zone is the "sweet" spot for injection. BUT it is also the zone where you have the biggest forces. Therefore BOSCH says that end of injection has to end (0.3 mm) before the max. speed point which is at 4 mm plunger travel from BDC for M pumps with 7 mm total stroke and ~5 mm for MW pumps with total stroke of 8 mm.
Btw. this is the ~ 60% I speak of before.
You need low plunger speed at the beginning to get the fuel into the barrel (and to avoid erosion (correct word?) between plunger edge and inlet bore edge when the effective stroke starts).
During the effective stroke the speed raises fast to provide good atomisation. Going further: with an IP maxed out you push end of injection beyond the max. speed point that means you are still within effective stroke but after passing the max. speed point (what is stressing the IP according to BOSCH) the plunger speed decreases resulting in inefficiency (like a racer slowing down before finishing the race).
This convinced me to go for larger elements. Providing the required fuel (stock + xx%) well before the sweet spot.

Commenting your last sentence:
Without thinking in detail I would say when you are within the effective stroke the pressure raise should be fast and short. Look at the common rails, they want to open the injector even faster than an spring can react (besides multiple injection,..). But all this can be modified with DV, pop pressure and nozzle. Important (in my opinion) is to create a short hard pressure peak coming from the IP and being smooth when filling the barrel and starting the effective stroke. This is the basic for the calculation of elements!

Tom

How about the rest of the system that was designed to supply a stock amount of fuel to a stock motor +-%?

__________________
1987 SDL. The best there ever was.

The key here is ask and answer questions without prejudice. Share your experience and observations and let others do the same. Being acidic and judgemental; no matter what your experience level is counter productive- and even if you have the right advice no one wants to hear it if your delivery tone is consistently harsh. If you are reading and taking advice here on the performance section you ought to have the basic understandings of a stock engine. Goatman you may have some experience and great questions- ask away and give us your experience. FI has experience and done some advanced work which have all appreciated- but so has myself, BC, Winmutt, H2Odiesel, GSXR and many, many others. BC and the mods here are basically asking those that post here to be civil and polite. If people post questionable advice then it'll shake out as questionable.

Tom,

I knew you were the guy to ask regarding this line of thought. It is ashame about the erosion issue as I definitely saw a performance increase with the .007" shims.

Question; is the start of injection height the same for the NA and Turbo MW IPs? The basis for the question is the higher pop pressure of the turbo injectors has a retarding effect on the actual start of injection due to line swell, (that is my understanding), would that delay put the end of injection closer to the sweet spot?

I am in total agreement with you about going with the larger elements, but for the sake of discussion, is the concern the end of injection pressure, or is it the volume at pressure (velocity) that is the concern?

Given that question, if the stock MW element helix and barrel port were capable of flowing a higher volume of fuel, that would reduce the velocity of the bypassing fuel at the same pressure, yes? If that theory is correct then by increasing the bypass capacity, the end of injection could be in the sweet spot with out damage? I would imagine that a lower injector pop pressure would help as well.

I have been following the quest for 8mm elements closely. I need to make the hybrid Prechanbers for my 617.95 and 616.912 (Turbo) first, but then I am going to upgrade the elements. How are your new elements coming?

Dave

Supply the proof/data on this additional 60hp.


Note: Threads on Boosted lift pump/supply pressure.

Fuel pressure relief valve adjustment
Fuel pressure relief valve adjustment

What does the cigar hose do....
What does the cigar hose do....

Fuel injection pump starvation with good a good lift pump
http://www.peachparts.com/shopforum/diesel-discussion/247039-fuel-injection-pump-starvation-good-lift-pump.html#post2133911

Still waiting for all of my questions to be answered. The more they go unanswered, the more confident I am that my theories are correct.

__________________
1987 SDL. The best there ever was.

EDIT:

I was wondering as well about a more aggressive cam lobe being useful for delivering more fuel per injection. Think of it this way:

Axiom 1: The injector line flexes. This has to be for a lot of reasons (think about it)

Given Axiom 1, what happens when the pressure rise occurs faster? Less energy goes into flexing the line (because maybe the line doesn't flex that fast), therefore more fuel gets through the gate (injector) and into the precombustion chamber.

What do you guys think? Anyone got a camera that can do 1000FPS at a super-close focus?

__________________
99 E300 Turbodiesel 100k

Pressure rises faster, line flexes faster. Doesn't work any other way.... You can't put 10lbs of poop in a 8 lb bag and expect it not to give, no matter how fast you do it.


So, since no one is willing to answer my other questions, who's made the most HP with a 603 to date?

__________________
1987 SDL. The best there ever was.

The lines do not act as a pressurized reservoir - ballooning to a max then releasing potential energy.

They are a conduit for pressurized events - a shockwave, if you will. Think: sunami.... where does it originate? How does it get to land? How is if manifest?

__________________

so, it looks like there aren't many options for performance nozzles? it sounds like monarch makes good stock like replacement units - but what about higher flowing nozzles?

what size elements have most used? 6mm-10mm? what are the bosch part numbers?

what is the factory turbo? compressor/turbine specs? compressor map?

how is the timing adjusted on these pumps? i'm guessing it's like a P7100 where the gear is broken free and the pump is rotated? can the same p-pump tools be used?

mike

erosion is not an issue when testing for some days, but this is the theory, and the reason why BOSCH took care of that.

the delivery valves compensates the difference for pop pressures to set the start of injection to the same value (24deg BTDC also for the 124 series).
I am not sure if I understood well "start of injection height". The book calls it "pre-lift" meaning the ~2 mm plunger stroke from BTDC before the the plunger edge closes the feeding bore and delivery starts. The DV of the turbo has a very short stroke to open compared to the NA (never had a NA MW but it is like this for the M) and a harder spring. All this playing together puts all the IPs and all pop pressures to the same result (start of delivery 24 deg).
That delay would push the safe and effective range of usable plunger stroke beyond the sweet spot (the cam moves on, not sure whether there is a difference in cam profile).
the first concern is that the injection lasts too long and the fuel can not burn completely (smoke without power). Second, the book says that (besides of smoke) the forces for the IP get too high when the element is used beyond the ~60% of the stroke (in sense of effective stroke). This zone is suboptimal also because the plunger is beyond its max. speed and starts to slow down. In my understanding the concern is velocity and therefore loss of spray capability.

I can not follow you here. What is bypassing fuel? Remember that the plunger has to open the feeding bore (not complete but 2/3). This gives the plunger a certain speed when its top edge closes the bore. This is the moment when it comes to erosion.
the discussion of a group buy died when someone wanted to buy the 8 mm elements in China. But anyway nothing from a different IP will fit perfectly. The cam of the IP where the 8mm elements come from has 10 mm lift, ours only 8 mm.
My first generation (6mm MW) are running fine. Currently I am upgrading my turbo and exhaust then we will see what potential these have.
But meanwhile I learned more and designed a new type. 6.5 mm MW but with the helix precisely respecting the a.m. and an improved feeding port!
Hope to get the prototype set pushed after my business trip (today for 2 weeks).

Tom (sorry for the long text)

Review the links in my last post for data on boosting injection pump supply pressure.


Summary of diesel tuning theory (mechanical injection only)
http://www.peachparts.com/shopforum/diesel-performance-tuning/216322-summary-diesel-tuning-theory-mechanical-injection-only-post1791112.html

Mercedes as a drag strip car
http://www.superturbodiesel.com/std/mercedes-as-a-drag-strip-car-t-3.html