Thread Rating:
  • 6 Vote(s) - 4.33 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Prechamber Mod "Flame" Front
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#1
Prechamber Mod "Flame" Front
I put together a MW with modded 10mm elements for a friend of mine about a month ago. He was on a budget so I did not regrind the IP cam, but did do the other changes I thought were necessary.

He put about 900 miles on it before the trans went bang and spit fluid out its side. The entire drive train is locked up and one of the CV cans is split. We went for a tuning ride and had a hell of a time getting it to not slip under power. In a desperate attempt, he unplugged the modulator signal, and it would squawk the tires when it shifted under mild load.

Unfortunately after 30mins of hard shifting, the trans said enough and stopped playing. When the trans shifted the engine hardly slowed down, the trans just slipped, shuttered, or the tires spun, and after a while of that kind of abuse....not totally unexpected.

The good news is the modified elements worked well, (only 900 miles on the clock), and the governor settings were basically stock.

The bad news is the car will be down until spring at least. I am trying to talk him into putting his engine on my dyno, but he is not all that keen about that, yet.

(This post was last modified: 01-24-2011, 01:55 PM by OM616.)
01-22-2011, 11:42 AM
Find Reply
DeliveryValve Offline
Superturbo
*****


Posts: 1,338
Joined: Feb 2008
Location:
#2
RE: MW Super Pump
I've have been following your thread on peachparts and hoping you get some success out of those elements. Good job, it would be great to hear it gets all straightened out and see some dyno numbers.




.
Gota love Mercedes Diesels!



.
01-22-2011, 12:59 PM
Find Reply
garage Offline
Bush Taxi
*****


Posts: 893
Joined: Jul 2009
Location: Cherry Valley, CA
#3
RE: MW Super Pump
(01-22-2011, 12:59 PM)DeliveryValve Wrote: I've have been following your thread on peachparts and hoping you get some success out of those elements. Good job, it would be great to hear it gets all straightened out and see some dyno numbers.




.

Your signature is my new favorite!!!!
Thats some serious Mercedes lovin right there!!
1987 300D: EGR Delete, ARV Delete, Cold Air Intake...
01-22-2011, 03:08 PM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#4
RE: MW Super Pump
(01-22-2011, 12:59 PM)DeliveryValve Wrote: I've have been following your thread on peachparts and hoping you get some success out of those elements. Good job, it would be great to hear it gets all straightened out and see some dyno numbers.

His would be a good engine to put on the dyno as it has Stage III Prechambers and the cam, (valve train), is advanced a touch more than new spec.

It has "unmolested" injectors at the 135 bar pop pressure and I would prefer to run honed injectors at 150+ bar. It did run very strong, revving very quickly, and the boost came up quickly as well.

The car owner works at a pump shop, and we were told as long as we were not charging for the work we were doing, that we could use a back up machine in the back to play with. I put my digital interface setup on the machine so I could get a baseline fueling curve, as I wanted to see the difference in performance with the same fueling curve, but larger elements.

I did put a stronger spring in the Torque Control Capsule to help match the fuel curve, but other than that, the settings are very mild and I was able to match the base line fueling curve +-.

We may pull the pump and tear it down for an inspection and then I would want to grind the cam.


01-22-2011, 03:30 PM
Find Reply
dieselboy Offline
Rotatin 5500 times a minute
****


Posts: 680
Joined: Dec 2010
Location: san diego
#5
RE: MW Super Pump
Hmm. Good thing I have a spare trans for when I put my 10mm elements in.

Do you happen to remember what the adjustments were on the pump to get it to run good? What boost were you running?
-Jesse

80 300sd hy35, front mount intercooler, w115 intake, rack limiter removed, Alda removed, full load turned up, boost, ebp, trans, pyro, egr delete, 3.5" exhaust, e-fan, 16x8 rims with, 245/50 tires, lowered, bilstien 5100's, 12" front brakes, 2.65:1 diff.
97 f250 psd 4x4, crawler
70 f250 390
83 Volvo 242, lots of mods
66 Volvo amazon

10 mistsubishi fuso service truck.
01-22-2011, 03:51 PM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#6
RE: MW Super Pump
(01-22-2011, 03:51 PM)dieselboy Wrote: Hmm. Good thing I have a spare trans for when I put my 10mm elements in.

Do you happen to remember what the adjustments were on the pump to get it to run good? What boost were you running?

Unfortunately nothing about this pump is comparable to any other.

I start with a 10mm P-Pump element and then alter the plunger helix and barrel, so the fuel out put increase per degree of plunger rotation is very different than the elements you will be getting, and there for the governor settings will be completely useless to anyone else.

I have looked at several different 10mm elements and they all have different plunger helix angles and heights for specific applications. I chose the one I am using because they are perfect for a shortened stroke.

As a reference, I turned up his stock pump to the point where it started to smoke under full power with 15lbs of boost. I would have to check my notes but I think I gave the TC 2 or 2 1/4 turns, and put a longer screw in the High Idle to delay fuel reduction until 5000 RPM.

I recorded the out put of the turned-up stock pump first, and then set the Super Pump to put out as close to the same curve. I am pleased how well it tuned and have some changes in mind for the next build.

Although we did not get a chance to increase the fuel, I am fairly confident that it would take more fuel while maintaining the 15PIS boost. I say this because the EGTs were cut in half compared to the turned-up stock pump.
01-22-2011, 04:11 PM
Find Reply
DeliveryValve Offline
Superturbo
*****


Posts: 1,338
Joined: Feb 2008
Location:
#7
RE: MW Super Pump
(01-22-2011, 03:08 PM)garage Wrote: ...
Your signature is my new favorite!!!!
..

Thanks I dig it too.


(01-22-2011, 03:30 PM)OM616 Wrote:
(01-22-2011, 12:59 PM)DeliveryValve Wrote: I've have been following your thread on peachparts and hoping you get some success out of those elements. Good job, it would be great to hear it gets all straightened out and see some dyno numbers.

His would be a good engine to put on the dyno as it has Stage III Prechambers and the cam, (valve train), is advanced a touch more than new spec...


We may pull the pump and tear it down for an inspection and then I would want to grind the cam.

You'd have to explain what are Stage III Prechambers. My understanding is the stock Prechambers are just fine for higher HP output and any modification would hinder and not improve performance.


If you get it dyno'd it would be interesting to see how the cam mod would effect before and after.



.
Gota love Mercedes Diesels!



.
01-22-2011, 05:52 PM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#8
RE: MW Super Pump
[/quote]
You'd have to explain what are Stage III Prechambers. My understanding is the stock Prechambers are just fine for higher HP output and any modification would hinder and not improve performance.

If you get it dyno'd it would be interesting to see how the cam mod would effect before and after. [/quote]

I really don't want to get into the prechamber at this point as it is a FLAME source if you get what I am saying. If you have not seen my thread on prechamber modifications here is a link:

http://www.peachparts.com/shopforum/show...p?t=232935

Unfortunately you really need to read through the entire thing as there are some good technical discussions here and there. I have not posted the testing that I have done because with out dyno numbers it becomes a flame/pissing, that’s not how it works, thread.

I agree the dyno would provide some good information regardless if it is what we want here or not. Advancing the cam timing "typically" gives an engine more bottom grunt. But as you said, it would be good to see what is really going on. It felt like the bottom end was improved and the turbo seems to spool quicker after the timing change.
01-22-2011, 07:08 PM
Find Reply
ForcedInduction Offline
Banned


Posts: 3,628
Joined: Feb 2008
Location: Hell
#9
RE: MW Super Pump
(01-22-2011, 05:52 PM)DeliveryValve Wrote: You'd have to explain what are Stage III Prechambers.
There is no such thing. OM616 simply hacks up his prechambers thinking there is a benefit.

Quote:My understanding is the stock Prechambers are just fine for higher HP output and any modification would hinder and not improve performance.
They are, you're correct.

Quote:I really don't want to get into the prechamber at this point
Why? The answer is simple, you're afraid those people that know what they are doing will prove you wrong. If you have any shread of factual data to back up your modifications, now is the time to bring it forward, otherwise your "stage III prechambers" will continue to be on the same plane as "cold air intakes" (though modifying the prechambers as you have is actually detrimental to the engine).
01-23-2011, 11:11 AM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#10
RE: MW Super Pump
I am sure that everyone would prefer to have a technical discussion with some depth instead of, that is not right, doesn’t work that way etc, one liners, as such, a statement or position based on what some one, (regardless of there origin), says, and or has, or has not done.

Consider this an opportunity to impress the forum with your technical knowledge in the operational theory of the "617a" prechamber, and how the aspects of the "617a" perchamber operational theory affect the overall performance and efficiency capabilities of the OM617a engine.

Further, one could really show some insight into their knowledge, and expand on the operational theory of the “617a” prechamber and point out what aspects of the “617a” precahmber could be improved to increase torque, and or, horsepower. Mind you that I did not mention anything about emissions, that is MB’s concern, I am strictly looking got improve torque and horsepower.





01-23-2011, 11:54 AM
Find Reply
ForcedInduction Offline
Banned


Posts: 3,628
Joined: Feb 2008
Location: Hell
#11
RE: MW Super Pump
OM616, instead of just running away from the discussion, how about you post some relevant information about it instead?

Quote:Consider this an opportunity to impress the forum with your technical knowledge in the operational theory of the "617a" prechamber, and how the aspects of the "617a" perchamber operational theory affect the overall performance and efficiency capabilities of the OM617a engine.
Everything needed is here: http://papers.sae.org/780633/

Quote:Further, one could really show some insight into their knowledge, and expand on the operational theory of the “617a” prechamber and point out what aspects of the “617a” precahmber could be improved to increase torque, and or, horsepower. Mind you that I did not mention anything about emissions, that is MB’s concern, I am strictly looking got improve torque and horsepower.
Please do, I have yet to see anything of the sort out of you.
01-23-2011, 12:09 PM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#12
RE: MW Super Pump
I see that you are taking the position that the accuser need not prove his accusations, putting the burden on the accused to prove the accuser incorrect. Tactically a good move for the sake of argument and politics, but as for a technical discussion, it prohibits both sides from presenting apposing technical points.

Again, one line referencing of information that some one else did, in this case an ASE study, is not a response with any technical depth. Supreme executive power comes from a mandate from the masses, not some fascicule aquatic ceremony. Look if I went around telling everyone that I was an emperor, because some moistened bink herald a cemitare at me they would put me away! (That just seemed relevant)

Moving right along, I will agine provide you with an opportunity to voice your technical and theoretical depth. For those who have not such vast experience and knowledge, could you write up a précis, (summery), of the study you have sighted, you know, put it laymen’s terms. Of course that will require more than say five or six complete paragraphs.

Will be gone for a bit, look forward to continuing this stimulating exchange.
(This post was last modified: 01-23-2011, 01:12 PM by OM616.)
01-23-2011, 01:08 PM
Find Reply
jeemu Offline
"some people do, some people talk."
****


Posts: 457
Joined: Nov 2009
Location: Finland
#13
RE: MW Super Pump
[Image: full] Cool
OM605 600hp diesel drag car build with BMW E30 chassis
01-23-2011, 01:18 PM
Find Reply
300D50 Offline
Graphite Moderator, ala RBMK
*****


Posts: 775
Joined: Aug 2009
Location: CNY
#14
RE: MW Super Pump
Looking over the various patents, and the documentation that tomnik posted in the peach thread, there might be some merit to prechamber modification.

Then again, we'd need definitive testing to see just how much of a difference there is.

Jeemu, might I ask what's been done with those? Smile
1990 Power Ram 50 V6 SOHC 24V 6g72

I can be wrong, don't take everything I say as verbatim, please fact-check first.
My posts are my personal opinions and thoughts, unless otherwise noted.
01-24-2011, 02:12 AM
Find Reply
ForcedInduction Offline
Banned


Posts: 3,628
Joined: Feb 2008
Location: Hell
#15
RE: MW Super Pump
(01-23-2011, 01:08 PM)OM616 Wrote: I see that you are taking the position that the accuser need not prove his accusations, putting the burden on the accused to prove the accuser incorrect.
I don't need to prove anything since Mercedes' team of engineers already did the all work over the last 50 years and were nice enough to publicly document it.

Quote:Again, one line referencing of information that some one else did, in this case an ASE study, is not a response with any technical depth.
Okay then, lets see your ASE paper.


jeemu, are those stock?
(This post was last modified: 01-24-2011, 09:27 AM by winmutt.)
01-24-2011, 09:05 AM
Find Reply
jeemu Offline
"some people do, some people talk."
****


Posts: 457
Joined: Nov 2009
Location: Finland
#16
RE: MW Super Pump
(01-24-2011, 09:05 AM)ForcedInduction Wrote: jeemu, are those stock?
No.
[Image: full]
OM605 600hp diesel drag car build with BMW E30 chassis
01-24-2011, 09:20 AM
Find Reply
Biohazard Offline
Smokin like a champ!
****


Posts: 376
Joined: Feb 2010
Location: NW Washington
#17
RE: MW Super Pump
Jeemu, I've been wondering if you had dyno'd the car before/after putting those in. I read through your build a while back, but don't recall if you had them in and running? Any difference?
82 300SD aka The Flyin Pumpkin (Gone): 7.5mm super M-pump, T3 60 trim turbo, Coldish air intake, A/W intercooler, propane injection, SW Boost and EGT gauges, Monark 265 nozzles, ported/polished cylinder head.

84 Euro 300D 4 sp: White with black trunk and hood. Blue cloth interior. Manual everything. 300DT front swaybar. C320 17" wheels. Now with the Flyin Pumpkins engine! 
01-24-2011, 09:53 AM
Find Reply
ForcedInduction Offline
Banned


Posts: 3,628
Joined: Feb 2008
Location: Hell
#18
RE: MW Super Pump
How did you determine they needed modification, how much power were you putting out when you decided to change them, how much to modify the holes and the effectiveness of the modification?
01-24-2011, 09:54 AM
Find Reply
dieselboy Offline
Rotatin 5500 times a minute
****


Posts: 680
Joined: Dec 2010
Location: san diego
#19
RE: MW Super Pump
They've been modifying precups for years in the idi's.
-Jesse

80 300sd hy35, front mount intercooler, w115 intake, rack limiter removed, Alda removed, full load turned up, boost, ebp, trans, pyro, egr delete, 3.5" exhaust, e-fan, 16x8 rims with, 245/50 tires, lowered, bilstien 5100's, 12" front brakes, 2.65:1 diff.
97 f250 psd 4x4, crawler
70 f250 390
83 Volvo 242, lots of mods
66 Volvo amazon

10 mistsubishi fuso service truck.
01-24-2011, 12:17 PM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#20
RE: MW Super Pump
(01-24-2011, 09:05 AM)ForcedInduction Wrote: I don't need to prove anything since Mercedes' team of engineers already did the all work over the last 50 years and were nice enough to publicly document it.

OK, Just to be sure that I understand your technical understanding and position regarding the 617a prechamber; you are telling everyone that your position is based on some one else’s efforts, (in this case MB), and not your personal technical / theoretical knowledge. In other words, you are declaring that your position is based solely on what you read, and that MB perfected them to make the maximum power before they released a single engine.

Nothing wrong with that, it just limits your understanding to the perspective of those whom have published the information that you rely on for all your knowledge. "Trust, but verify", I guess you trust more than verify.

I am trying to find some depth to you, some outside the box understanding of theory, but all we get back are one liners referencing others understanding, (from their Perspective), and work. I and sure we would all be thrilled to read about your theories. I could help you out and try to paste together a paragraph using all your one liners, but there isn't much technically relevant to work with in them.

You have a following of believers, although I see that some have broken from the flock recently. I agine am providing you an opportunity to show an example of depth, of some knowledge of theory that you have obtained yourself, that is, not solely from something you have read. Anything, we don't care at this point.

(01-23-2011, 01:08 PM)OM616 Wrote: Again, one line referencing of information that some one else did, in this case an ASE study, is not a response with any technical depth.

(01-24-2011, 09:05 AM)ForcedInduction Wrote: Okay then, lets see your ASE paper.

We are not talking about ASE's technical depth. Lets stay on point here. The previous post offered you the opportunity for you to demon straight your technical depth, and understand of theory, by disseminating the massive amount of information in the ASE report, (which has to be purchased), and translate the portions you think are relevant to this topic, and which are the bases of your position, so that all of us can have a clear understanding of where you are coming from, technically that is.

For an example of such written constructions, go to my thread http://www.peachparts.com/shopforum/show...p?t=232935
Several people have written very good technical agruements based on their understanding, and some of mine are in there as well as it is my thread. Also I thought it would be aproprate to copy and paste a PM that I responed to the other day.

Senders identity is with held to protect the innocent;

“Figured I'd ask via PM so there's no flame war started.

Happen to have any more info on how the torque curve/peak and hp curve/peak are related to the prechamber design? I'm looking through the peachparts thread, some good musings in there, maybe I just haven't hit the real good stuff yet.

Glad to see someone pushing the envelope in new and different ways!

Hope all is well,

XXXXX”


Relevant portions of my response;

Any way, I have measured the pressures in the cylinder and prechamber during compression, (pressure differential), at different piston velocities, and found that above 2000RPM the 616/617a prechamber VE really starts to fall off. Boost increases the cylinder pressure, and in turn helps the prechamber VE, but also creates tremendous pre-injection cylinder pressures and temperatures.

With out increased fuel delivery at the bottom end, the torque will not vary much because the prechambers VE is adequate for the slower piston velocities and expansion volume from the quantity of fuel that is delivered over the length of time, by the stock elements. The benefits of increasing the high speed VE of the prechamber can be seen in the drop in EGTs at high speed operation.

(After reading this again, I thought I would expand on the thought. The prechamber seems to be calibrated around a couple of variables, 1) being piston velocity and max cylinder volume, and 2) the pulse width of the injection, which for the most part sets the rate of expansion by slowly injecting fuel over a long time vrs, the same amount of fuel in ½ the time. With the slower injection, the pressure builds slower and can be bled through smaller holes over a longer period of time, allowing sufficient residual pressure to be sustained in the prechamber after the cylinder pressure has dropped. If larger elements were used, a given amount of fuel would be injected faster and the pressure curve would be steeper, (would riser quicker), there for, higher flowing holes would allow a faster release of the pressure, (more torque). Since the injection was shorter, the length of time the sustained pressure would need to be maintained to support continued combustion would be less. My goal with the 10mm elements is to be able to get the fuel injected and burnt before the cylinder pressure starts dropping, at that point the holes as calibrated orifices are not needed, and I can get as close to a direct injection with an external combustion chamber as I can get.

On the other side, if the boost is increased, the max cylinder volume is increased, which will require higher flowing holes to allow the additional air to make it into the prechamber at high piston velocities. Now one could argue that with out additional fuel, the increased holes would allow the prechamber pressure to drop too soon. Possible, I would point out that there is a higher volume of gasses in the prechamber creating a higher pressure at the start of injection. As long as the pressure stays above that which is needed to promote complete combustion for the length of time that is required to burn the injected fuel, all should be well and balanced)

The governor reduces the fueling at high speeds because the prechambers can't breath that well, and the fuel needs to be reduced to that which can burn in the lower O2 environment. In other words, the holes are sized for an engine operating speed of 55 mph at most, any faster and the increased volume of expansion gasses from the additional fuel needed, to run faster or make more power, simply can't get out of the prechamber before the next compression cycle starts. (At high speeds the prechamber never fully depressurizes and scavenging is reduced resulting in a dirty combustion environment, which generates smoke and high EGTs). (Determined from my pressure differential tests on 616/617a prechambers)”

Now that there are many examples of how to structure a technical response, there really is no excuse why we can not see a multi paragraph counter argument. Apposing thoughts are productive as long as they are well thought out and explained in context with supporting foundation.


(01-24-2011, 12:17 PM)dieselboy Wrote: They've been modifying precups for years in the idi's.

Did you order the same 10mm elements that Shredator used?


(This post was last modified: 01-24-2011, 06:18 PM by OM616.)
01-24-2011, 01:23 PM
Find Reply
dieselboy Offline
Rotatin 5500 times a minute
****


Posts: 680
Joined: Dec 2010
Location: san diego
#21
RE: MW Super Pump
The Volvo thin elements? Thats what I ordered.
-Jesse

80 300sd hy35, front mount intercooler, w115 intake, rack limiter removed, Alda removed, full load turned up, boost, ebp, trans, pyro, egr delete, 3.5" exhaust, e-fan, 16x8 rims with, 245/50 tires, lowered, bilstien 5100's, 12" front brakes, 2.65:1 diff.
97 f250 psd 4x4, crawler
70 f250 390
83 Volvo 242, lots of mods
66 Volvo amazon

10 mistsubishi fuso service truck.
01-24-2011, 02:08 PM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#22
RE: MW Super Pump
(01-24-2011, 02:08 PM)dieselboy Wrote: The Volvo thin elements? Thats what I ordered.

Idea We should start a 10mm club!

Are you going to install them or farm it out?

01-24-2011, 04:19 PM
Find Reply
Captain America Offline
Boostin' & Roostin'
*****


Posts: 2,219
Joined: Jun 2010
Location: Riverside, California USA
#23
RE: Prechamber Mod "Flame" Front
I wanna be in the club!

1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag

AX15 Jeep Trans swap in progress....

01-24-2011, 04:41 PM
Find Reply
ronnie Offline
GT2559V
***


Posts: 179
Joined: Aug 2010
Location: VA
#24
RE: Prechamber Mod "Flame" Front
I must say this sounds very reasonable. The larger the hole the better it will flow at higher speeds. Think it would be of any value on a non turbo 616? I know right now I am most likely not fueling enough, but as I get it sorted out, then maybe?
01-24-2011, 07:03 PM
Find Reply
ConnClark Offline
GT2256V
***


Posts: 108
Joined: Mar 2008
Location:
#25
RE: MW Super Pump
I figured I would chime in on this.

An indirect injection (IDI) engine has one clear advantage over a direct injection (DI) engine, rpm range. The key factor for an IDI engine to providing power at a higher rpm range is the resistance to flow provided by the prechamber at higher rpms. DI engines don't have this resistance to the flow which is why the have a narrower rpm range.

A DI engine is limited in rpm by the expansion rate of the combustion stroke. Past a certain rpm in a DI engine the fuel doesn't burn fast enough to maintain high enough pressure to burn the fuel completely. The higher the rpm goes past this point in a DI engine the less fuel it can actually burn and extract power from.

In an IDI engine at lower rpms the resistance to flow in and out of the prechamber is negligible and the IDI engine behaves much like a DI engine. As rpms increase so does the resistance to flow in and out of the prechamber. At the RPM where a similar DI would start to loose its ability to burn fuel because of the rate of expansion of during the power stroke, the pressure in the IDI engines prechamber is kept higher by the resistance to flow. This allows IDI engine to burn more fuel at higher rpm ranges than a DI engine and thus produce more power at those rpm ranges.

On the OM 617a the size of the prechamber holes effects the power produced at higher rpms. In general, with bigger holes the power peak will be moved to a lower rpm and the torque peak will be at a slightly higher rpm and slightly higher in value. As the holes get bigger your IDI engine becomes a DI engine. In general, with small holes the power peak will move to a higher rpm and the torque peak will drop in rpm and be lower in value. As hole size decreases from being oversized the power peak will grow and move to a higher range. At some point it will reach a maximum value and then decreasing the hole size will reduce the peak power while continuing to move the peak to a higher rpm.

<Flame War snipped>
(01-24-2011, 01:23 PM)OM616 Wrote: Relevant portions of my response;

Any way, I have measured the pressures in the cylinder and prechamber during compression, (pressure differential), at different piston velocities, and found that above 2000RPM the 616/617a prechamber VE really starts to fall off. Boost increases the cylinder pressure, and in turn helps the prechamber VE, but also creates tremendous pre-injection cylinder pressures and temperatures.

Actually boost will drop the volumetric efficiency because it increases the density and thus the viscosity of the air. It does effectively increase the mass of air in the prechamber though.

Quote:With out increased fuel delivery at the bottom end, the torque will not vary much because the prechambers VE is adequate for the slower piston velocities and expansion volume from the quantity of fuel that is delivered over the length of time, by the stock elements. The benefits of increasing the high speed VE of the prechamber can be seen in the drop in EGTs at high speed operation.

The egt drop is probably due to less fuel being burned.

Quote:(After reading this again, I thought I would expand on the thought. The prechamber seems to be calibrated around a couple of variables, 1) being piston velocity and max cylinder volume, and 2) the pulse width of the injection, which for the most part sets the rate of expansion by slowly injecting fuel over a long time vrs, the same amount of fuel in ½ the time. With the slower injection, the pressure builds slower and can be bled through smaller holes over a longer period of time, allowing sufficient residual pressure to be sustained in the prechamber after the cylinder pressure has dropped. If larger elements were used, a given amount of fuel would be injected faster and the pressure curve would be steeper, (would riser quicker), there for, higher flowing holes would allow a faster release of the pressure, (more torque). Since the injection was shorter, the length of time the sustained pressure would need to be maintained to support continued combustion would be less. My goal with the 10mm elements is to be able to get the fuel injected and burnt before the cylinder pressure starts dropping, at that point the holes as calibrated orifices are not needed, and I can get as close to a direct injection with an external combustion chamber as I can get.

There is a rate limit to how fast you can burn the fuel dictated by the rate at which the fuel encounters oxygen. Dumping all the fuel at once can have the effect of using up all the O2 in the locality of the fuel. This can cause some of the fuel to hit the prechamber wall where it woun't burn very well. Spreading out the fuel delivery can promote better mixing by allowing the turbulence in the prechamber to replenish the O2 supply in the location of the fuel.

Quote:On the other side, if the boost is increased, the max cylinder volume is increased, which will require higher flowing holes to allow the additional air to make it into the prechamber at high piston velocities. Now one could argue that with out additional fuel, the increased holes would allow the prechamber pressure to drop too soon. Possible, I would point out that there is a higher volume of gasses in the prechamber creating a higher pressure at the start of injection. As long as the pressure stays above that which is needed to promote complete combustion for the length of time that is required to burn the injected fuel, all should be well and balanced)

The governor reduces the fueling at high speeds because the prechambers can't breath that well, and the fuel needs to be reduced to that which can burn in the lower O2 environment. In other words, the holes are sized for an engine operating speed of 55 mph at most, any faster and the increased volume of expansion gasses from the additional fuel needed, to run faster or make more power, simply can't get out of the prechamber before the next compression cycle starts. (At high speeds the prechamber never fully depressurizes and scavenging is reduced resulting in a dirty combustion environment, which generates smoke and high EGTs). (Determined from my pressure differential tests on 616/617a prechambers)”

The holes are sized to balance a high power peak and to give a range of rpm suitable for driving between the torque and power peak that matches the gearing (both the number of gears and the ratios). Also the peak power output of the OM617a is at 4250 RPM, much much faster than 55 mph.

Quote:Now that there are many examples of how to structure a technical response, there really is no excuse why we can not see a multi paragraph counter argument. Apposing thoughts are productive as long as they are well thought out and explained in context with supporting foundation.

I haven't done experiments but this is the knowledge I have gleaned from books on the the subject and several technical reports from NACA experiments where they tested several variables with prechambers.

If you increased the boost substantially I could see justification for enlarging the holes a little but not much.
01-24-2011, 07:47 PM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#26
RE: MW Super Pump
Now that is a perfect example of a technical counter argument! It should be noted that ConnClark was one of the members who contributed to my other thread.

I think we actually agree on more that first appears. I need to be more specific as to terminology.

I think we can agree that the purpose of the prechamber is to sustain a pressurized environment that supports continued combustion after the cylinder pressure starts to drop. (as the engine speed increases, the time that the cylinder pressure is at or above the pressure that is required to support combustion is less and less, there for, the prechamber maintains pressure longer, to aid in the combustion at high engine speeds).

When I spoke of power, I should have said torque to be specific. I agree that reducing the hole size will allow the engine to run faster, but due to the reduced flow capacity of the smaller holes, less air will be able to get into the prechamber and there for, the amount of fuel that can be burnt is reduced. This will allow the engine to spin up faster, but the torque will be very low. If I recall correctly, the OM617a engines peek torque is some where around 2K rpm, after that the torque starts dropping off, but because the RPM is increasing, the HP number increases.

One way to tune a prechamber is to increase the size of the holes until the max speed of the engine at full power is just above where you want it. This would allow the prechamber to breath very well at lower speeds, allowing an increased air density in the prechamber to burn lots of fuel, and the ability for the expanding gasses to get to the cylinder quick enough to perform work at high speeds.

The stock holes are sized to work with the stock amount of fuel. If the pump is turned up, increasing the amount of fuel that is injected, then there needs to be more air in the prechamber to burn it. One way to increase the air in the prechamber is to increase the boost, which creates incredible pressures and temperatures as not all the extra air can get into the prechamber. This pressure robs the engine of power as power is used to compress the air. Also the cylinder’s compressed air temps are tremendously high, I measured over 900 degrees F with only 15 lbs of boost, during some of the tests. This is before the fuel is injected.

By increasing the size of the holes (proportionately to the amount of boost and fuel increase), the pressure differential will be lower as more air will be able to get into the prechamber. This will lower the amount of power that is used up compressing the cylinder gasses, lower the cylinder compressed gas temperature, and put more air into the prechamber so more fuel can be burnt generating more torque at higher speeds.

The Stage III prechambers have the three 3mm hole area increased 15% each. On my NA 616 engine, this resulted in a stronger mid range and top end, and the EGTs dropped approximately 150 degrees at cruising speed of 75 mph, and I am able to give it more fuel than I could before to maintain that speed up hills, the EGTS climb slower with the larger holes. It pulls stronger as far as I dare spool it up to, than it did before.

Regarding your thought that my drop in EGTs is the result of less fuel being burnt due to the holes being too big, I am injecting the same amount of fuel with the enlarged holes as I was with the small holes. If less fuel was actually burned being burnt, then the EGTs would go to critical mass in a very short order. Unburnt fuel = high EGT, completely burnt fuel = lower EGT, the heat was converted into work instead of being pumped out the exhaust.

With the 617a, increasing the size of the holes resulted in a more dramatic reduction of EGTs, the turbo spooled sooner, the engine temp was lower as well. I was able to turn up the pump beyond the point where it was smoking with the stock sized holes. It ran very strong, but until I get an engine for my dyno, it is speculation as to any power increases or decreases.

Now, I bet my emission numbers are terrible, especially NOX as I am generating more heat because I have more air in my prechamber so that the additional fuel I am injecting can burn generating more heat.

I think a key to really being able to open up the prechamber is reducing the delivery time. Yes there is a point where you can deliver too much too fast, but we are not there yet.

Keep in mind how pitifully under powered these engines are, a 2.4l that puts out only 60-80HP at full steam, or a 3.0l turbo motor @ 120.

With everything, the prechamber is an exercise in compromise as you can easily have a high torque stump puller, or a low torque screamer with ease, the trick is getting the torque where you want it.

I am interested in your counter thoughts.

I hope more members will feel comfortable enough to add to this discussion.








01-24-2011, 09:26 PM
Find Reply
dieselboy Offline
Rotatin 5500 times a minute
****


Posts: 680
Joined: Dec 2010
Location: san diego
#27
RE: Prechamber Mod "Flame" Front
Awesome!! You guys rock.
(01-24-2011, 09:05 AM)ForcedInduction Wrote: Okay then, lets see your ASE paper.


That paper will work great for tp if you happen to run out.
-Jesse

80 300sd hy35, front mount intercooler, w115 intake, rack limiter removed, Alda removed, full load turned up, boost, ebp, trans, pyro, egr delete, 3.5" exhaust, e-fan, 16x8 rims with, 245/50 tires, lowered, bilstien 5100's, 12" front brakes, 2.65:1 diff.
97 f250 psd 4x4, crawler
70 f250 390
83 Volvo 242, lots of mods
66 Volvo amazon

10 mistsubishi fuso service truck.
(This post was last modified: 01-24-2011, 10:40 PM by dieselboy.)
01-24-2011, 10:36 PM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#28
RE: Prechamber Mod "Flame" Front
(01-24-2011, 09:05 AM)ForcedInduction Wrote: Okay then, lets see your ASE paper.

(01-24-2011, 10:36 PM)dieselboy Wrote: That paper will work great for tp if you happen to run out.

LOL!!!!!!.... your killing me here..

But respectfully, the report does have some good measurement data.

I was just thinking, Jeemu's engine has smaller displacement cylinders compared to the 616 and 617. If you compare the 61X prechamber to the 60X prechamber, the first thing I notice is the 60X prechamber has a lot more holes of pertinent size, which go all the way around the tip, where the 61X prechamber has only 3 serious holes, two about 1/2 the area holes on the back side, and a tiny one in the end. The 60X can expel gasses 360 degrees because the prechamber is straight up & down, and is basically centrally located in the cylinder, where the 61X prechamber is on an angle to one side of the cylinder.

The point is if you add up the area of the 60X holes, (especially Jeemu's enlarged ones), and ratio the area to the displacement of the cylinder, and then take the area of the 61X holes and ratio those to the displacement, I wonder which engine has a better hole area to displacement ratio.

I need to look through my manuals and find the hole specs for the 60X engine. I may still be on the conservative side. Just trying to come up with comparable data that can be referenced to a known.



01-24-2011, 11:40 PM
Find Reply
ForcedInduction Offline
Banned


Posts: 3,628
Joined: Feb 2008
Location: Hell
#29
RE: MW Super Pump
*Information removed at "moderator" request to stop somebody from crying.

OM616, once again you've managed to type so much while saying absolutely nothing.

(01-24-2011, 07:03 PM)ronnie Wrote: The larger the hole the better it will flow at higher speeds.
ronnie, flow is not a good thing in a prechamber, thats why it was designed with orifice holes.
The concept behind a prechamber is to atomize the fuel; it does this with by burning a very small amount of fuel inside the prechamber, which blows out the vaporized fuel for it to burn in the cylinder. Increasing the volume of air inside the prechamber is pure wasted energy, the combustion pressure is pushing on the prechamber walls instead of the piston.

People like Jeemu have validity in modifying them because the large volume of fuel injected becomes restricted from flowing out of the prechamber. Jeemu is making 220hp per liter, OM616 is still making only 72hp total.

(01-24-2011, 10:36 PM)dieselboy Wrote: That paper will work great for tp if you happen to run out.
What paper? OM616 has not published anything to SAE.

Quote:the report does have some good measurement data.
Still waiting for yours. Have you got any non opinion/feel/guess based measurements? Even a measly before and after dyno so you can have some form of foundation for your idea?
(This post was last modified: 01-27-2011, 05:08 PM by ForcedInduction.)
01-25-2011, 12:16 AM
Find Reply
dieselboy Offline
Rotatin 5500 times a minute
****


Posts: 680
Joined: Dec 2010
Location: san diego
#30
RE: Prechamber Mod "Flame" Front
Lol I remember when I thought I knew it all too. You have alot to learn and these people are trying to teach you. You are young absorb it.


-Jesse

80 300sd hy35, front mount intercooler, w115 intake, rack limiter removed, Alda removed, full load turned up, boost, ebp, trans, pyro, egr delete, 3.5" exhaust, e-fan, 16x8 rims with, 245/50 tires, lowered, bilstien 5100's, 12" front brakes, 2.65:1 diff.
97 f250 psd 4x4, crawler
70 f250 390
83 Volvo 242, lots of mods
66 Volvo amazon

10 mistsubishi fuso service truck.
01-25-2011, 02:57 AM
Find Reply
Spaceraver Offline
K26-2
*


Posts: 40
Joined: Aug 2010
Location: Denmark
#31
RE: Prechamber Mod "Flame" Front
I'm keeping my eyes peeled on this one..
Jeemu. I have a non turbo OM606, that i want to convert to turbo, adding a intercooler and turbo is straight forward. Done turbo setups before. Tuning the pump is another matter..
Understanding that I can only pull 300 HP, Torque ?? max before the bottom end/connecting rods goes boom. Would i need to increase the orifices for say 250 hp? Larger elements? Or something completely other mod?
I wouldn't mind getting an STD..Tongue
01-25-2011, 04:43 AM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#32
RE: MW Super Pump
(01-25-2011, 12:16 AM)ForcedInduction Wrote:
(01-24-2011, 07:03 PM)ronnie Wrote: The larger the hole the better it will flow at higher speeds.
ronnie, flow is not a good thing in a prechamber, thats why it was designed with orifice holes.

The concept behind a prechamber is to atomize the fuel; it does this with by burning a very small amount of fuel inside the prechamber, which blows out the vaporized fuel for it to burn in the cylinder. Increasing the volume of air inside the prechamber is pure wasted energy, the combustion pressure is pushing on the prechamber walls instead of the piston.

That is better. So to be sure I have it right, your understanding of how the prechamber works is that a very small percentage of air is pushed into the prechamber, (would it be fair to say you are thinking less than 15%?), and that the injected fuel passes through the prechamber to the cylinder, propelled by a little fuel burning in the prechamber, and that the majority of the fuel 90+% is ignited and burnt in the cylinder.

It is important that I understand you correctly, in order to post a counter argument.



On a side note:

(01-25-2011, 12:16 AM)ForcedInduction Wrote: People like Jeemu have validity in modifying them because the large volume of fuel injected becomes restricted from flowing out of the prechamber. Jeemu is making 220hp per liter, OM616 is still making only 72hp total.

Did you intend to imply that when Jeemu starts his engine that it instantly, and only makes 220hp pre liter?, because that would it a hand full to say the least. What about when he doesn’t have his foot to the floor? You know, it has to idle and be able to putt around, making only 72hp total or less, like me, or are you saying that his engine runs like crap, smoke, high EGTs, no power, until he floors it?



Regarding some of my measurements, In my last post, I posted that I measured cylinder compressed gas temperatures in the 900+ degree F range, pre-injection, I have not posted, but during high speed piston velocity tests, I measured cylinder compressed gas pressures in upwards of 1000PSI and prechambre pressures (at the same time) of 280 to 315PSI range. The closest pressure differential was below the 2000 RPM range.

I also posted that I saw a drop in high speed EGTs and was able to increase fueling for the turbo motor beyond where it was smoking with the stock holes. The turbo built boost sooner, (at a lower RPM), as well.









(01-24-2011, 09:20 AM)jeemu Wrote:
(01-24-2011, 09:05 AM)ForcedInduction Wrote: jeemu, are those stock?
No.
[Image: full]

Jeemu,

Can you confirm if there are holes all the way around the tip. If so, I figure there would be 8 holes.

The manuals I have do not say what the hole diameter is or how many there are.

Many thanks.

(This post was last modified: 01-25-2011, 04:04 PM by OM616.)
01-25-2011, 11:01 AM
Find Reply
jeemu Offline
&quot;some people do, some people talk.&quot;
****


Posts: 457
Joined: Nov 2009
Location: Finland
#33
RE: Prechamber Mod "Flame" Front
Yes there is 8 on the side and one on the top or tip of chamber.
Dont remember original diameters of those holes. I do have one set of originals if measure needed.
This is need to done when go over 100hp/cyl
Faster injection is better as you all know.
Little add. Here is now at least 2 engine where is this much modified chambers.
Not really differens vs originals.
OM605 600hp diesel drag car build with BMW E30 chassis
(This post was last modified: 01-25-2011, 02:56 PM by jeemu.)
01-25-2011, 02:51 PM
Find Reply
casioqv Offline
OM602 Turbo
***


Posts: 116
Joined: Apr 2010
Location: Riverside, CA
#34
RE: Prechamber Mod "Flame" Front
This is a very interesting thread to read, but I feel like one practically needs a mechanical engineering PhD to make a useful contribution... so pardon my ignorance posting without one.

I wonder how these engines would run with the entire tip of the prechamber cut off, to essentially make them nearly a direct injection motor. I realize one would probably lose the entire upper rpm range, but would we gain more torque and efficiency like a DI engine?

If the engine were overall more efficient running at lower rpms with more torque, perhaps you could gain back the lost horsepower from the narrower rpm range by simply running more boost and fuel while retaining the efficiency improvement.

//edit: OR would the geometry of an IDI engine with the prechamber opened up make for a very poor running DI engine- having the injector way up inside a tube rather than spraying right into the piston? I suppose there's other differences too- I'm not sure why DI engines always have such low compression ratios compared to IDI ones.

Overall it actually sounds like IDI engines are better for high performance, but DI engines may be better for normal driving where efficiency and torque trump peak horsepower.
-Tyler
1984 Volvo 760GLE Turbo Diesel D24T/M46
1986 Isuzu Trooper Turbo Diesel
No mercedes (for now)
(This post was last modified: 01-25-2011, 03:06 PM by casioqv.)
01-25-2011, 02:59 PM
Find Reply
jeemu Offline
&quot;some people do, some people talk.&quot;
****


Posts: 457
Joined: Nov 2009
Location: Finland
#35
RE: Prechamber Mod "Flame" Front
(01-25-2011, 02:59 PM)casioqv Wrote: This is a very interesting thread to read, but I feel like one practically needs a mechanical engineering PhD to make a useful contribution... so pardon my ignorance posting without one.

I wonder how these engines would run with the entire tip of the prechamber cut off, to essentially make them nearly a direct injection motor. I realize one would probably lose the entire upper rpm range, but would we gain more torque and efficiency like a DI engine?

If the engine were overall more efficient running at lower rpms with more torque, perhaps you could gain back the lost horsepower from the narrower rpm range by simply running more boost and fuel while retaining the efficiency improvement.

//edit: OR would the geometry of an IDI engine with the prechamber opened up make for a very poor running DI engine- having the injector way up inside a tube rather than spraying right into the piston? I suppose there's other differences too- I'm not sure why DI engines always have such low compression ratios compared to IDI ones.

Overall it actually sounds like IDI engines are better for high performance, but DI engines may be better for normal driving where efficiency and torque trump peak horsepower.
No can cut tip of. Also it runs bad if you remove the "pearl" inside the chamber

OM605 600hp diesel drag car build with BMW E30 chassis
01-25-2011, 03:08 PM
Find Reply
OM616 Offline
10mm MW
****


Posts: 556
Joined: Jul 2009
Location: Michigan
#36
RE: Prechamber Mod "Flame" Front
(01-25-2011, 02:51 PM)jeemu Wrote: Yes there is 8 on the side and one on the top or tip of chamber.
Dont remember original diameters of those holes. I do have one set of originals if measure needed.
This is need to done when go over 100hp/cyl
Faster injection is better as you all know.

Thanks Jeemu,

Please forgive me, I am riding in a car, using a friends lap top, while carrying on a conversation, so if I have gone astray please feel free to correct me.

I an doing some quick number crunching and have some data that needs to be commented on by the gallery.

The stock 61X prechamber that I have in my hand has Three 3mm holes, and Two 2.5mm holes, (there is a tiny drain hole in the tip, but I am not counting that in either one), which when added up I get a total of .0480722 sqin of area.

Assuming that Jeemu's prechamber holes were 2.5mm to start with, and there is eight of them, then I get a total area of .060836 sqin.

Now, from the looks of the holes, I am betting that they were drilled to at least 3mm, X eight holes, I get .0876352 sqin.

Now the cylinder displacement of a 60X engine is less than the 61X;

(I am referencing my 603 manual), A 603 has cylinder displacement of 30.314866 cuin, and a 61X has a cylinder displacement of 36.036165 cuin.

If I divide the cylinder displacement of the 61X, 36.036165, by the 61X prechamber hole area, .0480722, I get a 749.62587 to 1 ratio

If I divide the cylinder displacement of the 603, 30.314866 cuin, by the 603 prechamber hole area @ 2.5mm dia holes, .060836, I get 498.30462 to 1

If I divide the cylinder displacement of the 603, 30.314866 cuin, by the 603 prechamber hole area @ 3mm dia holes, .0876352, I get 345.92111 to 1


If I look at these numbers a different way, I see that at 2.5mm, the 60X prechamber has about 26.5% more area than the 61X prechamber, and the 603 cylinder displacement is aprox. 15.7% less than the 61X.

At 3.0mm, the 60X prechamber has about 82.4% more area than the 61X prechamber, and the 603 cylinder displacement is aprox. 15.7% less than the 61X.

Have to stop here. Please comment. Will be back in a bit.



(01-25-2011, 02:59 PM)casioqv Wrote: This is a very interesting thread to read, but I feel like one practically needs a mechanical engineering PhD to make a useful contribution... so pardon my ignorance posting without one.

I wonder how these engines would run with the entire tip of the prechamber cut off, to essentially make them nearly a direct injection motor. I realize one would probably lose the entire upper rpm range, but would we gain more torque and efficiency like a DI engine?

If the engine were overall more efficient running at lower rpms with more torque, perhaps you could gain back the lost horsepower from the narrower rpm range by simply running more boost and fuel while retaining the efficiency improvement.

//edit: OR would the geometry of an IDI engine with the prechamber opened up make for a very poor running DI engine- having the injector way up inside a tube rather than spraying right into the piston? I suppose there's other differences too- I'm not sure why DI engines always have such low compression ratios compared to IDI ones.

Overall it actually sounds like IDI engines are better for high performance, but DI engines may be better for normal driving where efficiency and torque trump peak horsepower.

Everyone, Please do not be afraid to post your thoughts!!!!!!!!! Regardless of the harshness of a member, every thought on the subject has merit, and sometimes the simplest idea that might seem stupid at the time, can take the discussion in a totally different direction.

Surrounding ones self with people that think just like one, doesn’t promote progression. This is basically brainstorming, there really isn't a wrong answer regardless of what a member says. This is my thread, and I want to hear from everyone!!!!

(This post was last modified: 01-25-2011, 04:11 PM by OM616.)
01-25-2011, 03:40 PM
Find Reply
yankneck696 Offline
Build it so strong &amp; blow it up good !!!
****


Posts: 395
Joined: Aug 2009
Location: Pt. Charlotte FL
#37
RE: Prechamber Mod "Flame" Front
I am really starting to understand the idea here. That says alot, as I am blonde. Keep it going & get it done.
Ed
01-25-2011, 05:14 PM
Find Reply
casioqv Offline
OM602 Turbo
***


Posts: 116
Joined: Apr 2010
Location: Riverside, CA
#38
RE: MW Super Pump
(01-24-2011, 02:08 PM)dieselboy Wrote: The Volvo thin elements? Thats what I ordered.

These are from a Volvo industrial diesel with an MW pump?

Man, I'd *love* to have a Volvo wagon with a Volvo industrial diesel. Like the Volvo D3-110 inline 5 2.4 liter w/ 110hp@3000rpm. Although they weigh almost 700lbs so it would drive like crap (no offense to OM617 owners - lol)
-Tyler
1984 Volvo 760GLE Turbo Diesel D24T/M46
1986 Isuzu Trooper Turbo Diesel
No mercedes (for now)
(This post was last modified: 01-25-2011, 05:32 PM by casioqv.)
01-25-2011, 05:27 PM
Find Reply
ronnie Offline
GT2559V
***


Posts: 179
Joined: Aug 2010
Location: VA
#39
RE: Prechamber Mod "Flame" Front
From Forced,
"The concept behind a prechamber is to atomize the fuel; it does this with by burning a very small amount of fuel inside the prechamber, which blows out the vaporized fuel for it to burn in the cylinder. Increasing the volume of air inside the prechamber is pure wasted energy, the combustion pressure is pushing on the prechamber walls instead of the piston."

I do agree that this is the purpose of the prechamber. However at some point it must also hinder movement of fuel to the combustion chamber, ie cylinder. In the stock or nearly stock engine the holes are more then likely properly sized. However most of us on this forum are trying to get more power, and we are exceeding what Mercedes intended for these engines. So at what point are the holes to small to allow the power we are trying to achieve? This would/could also be that there is a interum area of possible power that would not need bigger holes to achieve the power wanted, but still could benifit by altering the combustion process such that egt's would be lower for a given power. I am afraid to say that this is all great theory, but testing an engine with the stock chambers then switching to the "improved" ones is going to be the only real answer. Of course one must have a theory to try, and it does sound plausible that small holes could be reducing the speed of fuel entering the cylinder, so naturally it would be reasonable to enlarge the holes. I see OM616 is doing the math to figure what other engines have, and comparing, this is a first step to deciding if indeed the holes are small, and also seeing what size to make a test set.
01-25-2011, 07:09 PM
Find Reply
ForcedInduction Offline
Banned


Posts: 3,628
Joined: Feb 2008
Location: Hell
#40
RE: Prechamber Mod "Flame" Front
(01-25-2011, 02:57 AM)dieselboy Wrote: Lol I remember when I thought I knew it all too.
*Information removed to stop somebody from crying.

(01-25-2011, 11:01 AM)OM616 Wrote: That is better.
What is better, the line I just repeated from a post I made a few weeks ago? You must have ignored that one too.

Quote:Did you intend to imply that when Jeemu starts his engine that it instantly, and only makes 220hp pre liter?
No, stop attempting to put words in my mouth it only makes you look like a troll.

Quote:In my last post, I posted that I measured cylinder compressed gas temperatures in the 900+ degree F range, pre-injection, I have not posted, but during high speed piston velocity tests, I measured cylinder compressed gas pressures in upwards of 1000PSI and prechambre pressures (at the same time) of 280 to 315PSI range. The closest pressure differential was below the 2000 RPM range.
I'm calling bullshit, again.

Quote:The manuals I have do not say what the hole diameter is or how many there are.
Just the FSM.

.jpg   Picture 1.jpg (Size: 42.69 KB / Downloads: 8,566)

(01-25-2011, 02:59 PM)casioqv Wrote: I wonder how these engines would run with the entire tip of the prechamber cut off
They wouldn't.

Quote:Overall it actually sounds like IDI engines are better for high performance
They are. People use IDI for two reasons; 1- Its cheaper. 2- They make power at higher RPMs, which inflates horsepower numbers while making low torque (The same way an F1 engine can make 900hp with only ~250lb/ft torque).

Quote:but DI engines may be better for normal driving where efficiency and torque trump peak horsepower.
Correct, right off the bat you get 15% more power and efficiency per/L by ditching the prechamber. The off side is more noise, the reason MB stuck with IDI for so long when companies like Audi/VW had gone DI 6 years earlier.

Quote:and sometimes the simplest idea that might seem stupid at the time
*Information removed to stop somebody from crying.

(01-25-2011, 07:09 PM)ronnie Wrote: However at some point it must also hinder movement of fuel to the combustion chamber, ie cylinder.
Hence the reason high-output people like Jeemu have merit in altering the hole diameter.

Quote:However most of us on this forum are trying to get more power
And you think I'm not?

Quote:So at what point are the holes to small to allow the power we are trying to achieve?
(01-25-2011, 02:51 PM)jeemu Wrote: This is need to done when go over 100hp/cyl
(This post was last modified: 01-27-2011, 05:09 PM by ForcedInduction.)
01-25-2011, 08:44 PM
Find Reply
casioqv Offline
OM602 Turbo
***


Posts: 116
Joined: Apr 2010
Location: Riverside, CA
#41
RE: Prechamber Mod "Flame" Front
(01-25-2011, 08:44 PM)ForcedInduction Wrote: Correct, right off the bat you get 15% more power and efficiency per/L by ditching the prechamber.

You forgot to type the letters "In" before "correct"

-Tyler
1984 Volvo 760GLE Turbo Diesel D24T/M46
1986 Isuzu Trooper Turbo Diesel
No mercedes (for now)
(This post was last modified: 01-25-2011, 08:51 PM by casioqv.)
01-25-2011, 08:50 PM
Find Reply
ForcedInduction Offline
Banned


Posts: 3,628
Joined: Feb 2008
Location: Hell
#42
RE: Prechamber Mod "Flame" Front
(01-25-2011, 08:50 PM)casioqv Wrote: You forgot to type the letters "In" before "correct"

No, occasionally somebody makes a statement that is rational and/or accurate.
01-25-2011, 09:13 PM
Find Reply
casioqv Offline
OM602 Turbo
***


Posts: 116
Joined: Apr 2010
Location: Riverside, CA
#43
RE: Prechamber Mod "Flame" Front
(01-25-2011, 09:13 PM)ForcedInduction Wrote: No, occasionally somebody makes a statement that is rational and/or accurate.

That never stopped you before.

Anyway- I prefer the properties of IDI engines despite their reduced efficiency.
(01-25-2011, 03:08 PM)jeemu Wrote: No can cut tip of. Also it runs bad if you remove the "pearl" inside the chamber

(01-25-2011, 08:44 PM)ForcedInduction Wrote: They wouldn't.

So you guys are saying it wouldn't even be able to start with the tip cut off? Why not? I'm not disagreeing, just curious for more information since I don't quite understand why IDI with no orifice would behave very differently from a DI engine.
-Tyler
1984 Volvo 760GLE Turbo Diesel D24T/M46
1986 Isuzu Trooper Turbo Diesel
No mercedes (for now)
(This post was last modified: 01-25-2011, 09:30 PM by casioqv.)
01-25-2011, 09:19 PM
Find Reply
Hercules Offline
GT2559V
***


Posts: 216
Joined: Nov 2010
Location: Fresno,Ca.
#44
RE: Prechamber Mod "Flame" Front
My two cents worth.In 1981 mbz increased prechamber hole size,in1982 hole size was reduced back to1981 level. Mbz stated,inorder to reduce piston crown temps. Why the increase in hole size? Mbz was looking for more power. (It did work) ... Not just theory. Only concerns of high piston crown temps. Now in 1985 Mbz again increased hole size to 1981 level,larger size. Have I done this,Yes, does it work,Yes. Noted results,Increased performance, quicker spool,pulls grades in high gear much better. Mbz did it. A little twist,not wanting to go larger than mbz did, I taper reamed all the holes. Larger outside hole smaller inside. Was trying to give flame front a little better direction,to spread more evenly. Results,Little or no smoking. Even wife commented after several months of use,that she had not seen any more smoking after those adjustments.
Well maybe that was three cents worth.
01-26-2011, 12:14 AM
Find Reply
ForcedInduction Offline
Banned


Posts: 3,628
Joined: Feb 2008
Location: Hell
#45
RE: Prechamber Mod "Flame" Front
(01-25-2011, 09:19 PM)casioqv Wrote: So you guys are saying it wouldn't even be able to start with the tip cut off? Why not?
There would be no way to distribute the flame front without either exploding the prechamber or cracking/melting the piston.

Quote:I don't quite understand why IDI with no orifice would behave very differently from a DI engine.
The two are nothing alike.
01-26-2011, 12:37 AM
Find Reply
300D50 Offline
Graphite Moderator, ala RBMK
*****


Posts: 775
Joined: Aug 2009
Location: CNY
#46
RE: Prechamber Mod "Flame" Front
If prechambers weren’t so expensive, I'd say one of us should do a dyno run with stock, then another with opened up prechambers, to help quantify the actual difference.

(01-25-2011, 09:19 PM)casioqv Wrote: That never stopped you before.
Far be it from me being holy, but that's utter trolling right there.


1990 Power Ram 50 V6 SOHC 24V 6g72

I can be wrong, don't take everything I say as verbatim, please fact-check first.
My posts are my personal opinions and thoughts, unless otherwise noted.
01-26-2011, 12:50 AM
Find Reply
Captain America Offline
Boostin' & Roostin'
*****


Posts: 2,219
Joined: Jun 2010
Location: Riverside, California USA
#47
RE: Prechamber Mod "Flame" Front
(01-26-2011, 12:50 AM)300D50 Wrote: If prechambers weren’t so expensive, I'd say one of us should do a dyno run with stock, then another with opened up prechambers, to help quantify the actual difference.

I've got an extra set, but it will be some time before I have a running motor to try this in... Undecided

1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag

AX15 Jeep Trans swap in progress....

01-26-2011, 01:00 AM
Find Reply
casioqv Offline
OM602 Turbo
***


Posts: 116
Joined: Apr 2010
Location: Riverside, CA
#48
RE: Prechamber Mod "Flame" Front
(01-26-2011, 12:50 AM)300D50 Wrote: Far be it from me being holy, but that's utter trolling right there.

Sometimes it seems like FI automatically responds with "incorrect" to anyone whom contradicts him, without carefully considering the reasoning and information they present.

However I agree that it was out of line and I apologize.
-Tyler
1984 Volvo 760GLE Turbo Diesel D24T/M46
1986 Isuzu Trooper Turbo Diesel
No mercedes (for now)
(This post was last modified: 01-26-2011, 01:13 AM by casioqv.)
01-26-2011, 01:12 AM
Find Reply
Captain America Offline
Boostin' & Roostin'
*****


Posts: 2,219
Joined: Jun 2010
Location: Riverside, California USA
#49
RE: Prechamber Mod "Flame" Front
It's too bad you cant have a conversation without getting beat down...

1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag

AX15 Jeep Trans swap in progress....

01-26-2011, 01:22 AM
Find Reply
ForcedInduction Offline
Banned


Posts: 3,628
Joined: Feb 2008
Location: Hell
#50
RE: Prechamber Mod "Flame" Front
(01-26-2011, 12:50 AM)300D50 Wrote: If prechambers weren’t so expensive, I'd say one of us should do a dyno run with stock, then another with opened up prechambers, to help quantify the actual difference.

Why use new? They're a penny/5 in the junkyards.
(This post was last modified: 01-26-2011, 01:57 AM by ForcedInduction.)
01-26-2011, 01:56 AM
Find Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)