edm or extrude honed? which is better for injector tips?
- Thread starter dmaxvaz
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The things to be unvieled by these two (Volker and Curtis)will be a positive turning point for the performance diesel market, Bar none!
to help answer your question, bigger nozzels(though possible) dont allways mean less pressure....or worse atomization..
Because we have a computer contolled fuel sytem it will adjust automatically to pressure drops and try to provide what the set PSI is, and the commanded PSI.
at idle set psi should be around 5-7kPSI depending on year and make, but with computer compensation PSI has not changed, but volume has(due to a bigger injector nozzel), more fuel is present at the same PSI, more fuel with no more air to match it will Somtimes result in a "Haze" at idle.
In short, I think thats what your seeing.......
The things to be unvieled by these two (Volker and Curtis)will be a positive turning point for the performance diesel market, Bar none!
I AGREE!!
....
at idle set psi should be around 5-7kPSI depending on year and make, but with computer compensation PSI has not changed, but volume has(due to a bigger injector nozzel), more fuel is present at the same PSI, more fuel with no more air to match it will Somtimes result in a "Haze" at idle.
In short, I think thats what your seeing.......[/QUOTE]
So why do some smoke and others don't? Is it just the process used making the difference here? Turbo used? In the VVT trucks that have them, are they closing vanes more at idle to spool a little more?
I've seen a few of these Duramax trucks with larger injectors (don't know who did the injectors) that smoke at idle so bad it'll burn your eyes if yours standing near by... I've also seen them with very large injectors and lowered CR that will haze ever so slightly until warmed up, then nada. Just like a stock truck.
Lends me to believe, at least for some of them, it could be somewhat in the low RPM tuning???
I have no doubts that things coming from Curtis and Volker will be amung the best available for the Duramax, period.
Lends me to believe, at least for some of them, it could be somewhat in the low RPM tuning???
I have no doubts that things coming from Curtis and Volker will be amung the best available for the Duramax, period.
super diesel
<<<< Under Pressure
I didn't say about less pressure unless your running wide open on a pump that can't hang in the first place. What I'm talking about is the larger diesel droplet going in that doesn't totally burn the entire droplet sinse it is now larger (may need more pressure for a finer misting and compleat burn of the injected droplets). Like we see in the P-pumped Dodges (I know, I had one) when they blow the black smoke from not being able to burn the whole mixture being injected (incompleat combustion = power left on the table).
For the Dmax trucks I've tuned with extrude honed injectors, mine included, they need a bit of tuning modification( pressure and pulse width) in the idle range to clear up smoke, . My truck with 30% honed injectors, does not smoke at idle even with cold winter start ups.
That being said Nathan's tune didn't need these changes as the EDM injectors didn't smoke with stock idle tuning. IIRC his are quite a bit larger than mine.
That is a huge problem. Two trucks with "identically advertised" injector flow rates can and often do act very different.
I didn't say rail pressure. imaging when the needle lifts, its like a valve opening and fuel wanna go around the needle tip and go thrue the holes. the holes are the throttle point which gives the opening timing of the needle and pressure timing! when the needle is complete open then the rail pressure has the full effect in the spray config. bigger holes = slower needle opening = black and white smoke
this phanomean is around 400 - 600 ms dipens on injector holes size
sorry for spelling, im on my blackberry
this phanomean is around 400 - 600 ms dipens on injector holes size
sorry for spelling, im on my blackberry
I'm fairly sure you mean 400-600uS (micro Second). Even so, that ends up being 7-10 crank angle degrees at 3000 RPM.
Fixed pop off injectors tended to respond faster with higher line pressures. How do these electronic ones respond as the pressures increase? Faster, slower or more or less the same delay.
we get them EDM'ed then extrude honed...
Better flow and better atomization.
That's the right way to do it IMO. You get rid of the surface imperfections
.
Originally Posted by mde View Post
Every OEM nozzle is first EDM'd, then extrude honed. They aren't extrude honed by the same process Extrude Hone the company uses.Which is the same process probably 99% of the aftermarket injector companies use.
I never said that they use Extrude Hone machines, but I said they use balancing extrude hone machine like Sonplas. Sonplas is the mayor extrude hone machine factory for diesel nozzles production, which you can adjust the flow you want. First the machine measures the actual flow called the Bosch number which meassures the flow by 100 bar and 40 degrees Celsius. The it extrude hones exactly to the value you need, cleans the nozzle and measures again. So never go to an extrude company and say you wanna 40% over ... tell him you wanna the 1.128 @ Bosch specification!!!
here a pic:
If you open the holes with extrude honing, you don't open the holes in % (or area) you decrease the resistance radius on the inside edge. When you extrude hone the nozzle, the seats don't get destroyed and don't causes the smoke by idle. The reason you get smoke is because when you the needle opens, you get to much pressure drop on the needle tip, which we loose atomization of the fuel and causes the smoke. Also the nozzle is slower in lower fuel pressure range and causes white smoke ... I'll argue this one too....I've run injectors that flow over 2x stock without white smoke at idle in a Cummins. When you get over 3x stock they will haze a bit. So while they do have a pressure drop at the tip you can erode the seat enough to cause heavy smoke at idle. I bet if you ask anyone that has a extrude hone machine that has tried to do really large injectors they will tell you the idle smoke is heavy even on a mechanical injector where they can raise the pop off pressure. With a raised pop off pressure it changes the pressure drop in the seat.
You don't need 2x - 3x bigger nozzles ... no wonder you break the tips off!!!
Also I never heard of a CR-nozzle cracked, split or broke the tip of. This new nozzles are made from better steel and newer hardening processes.I've heard of lots of them. Several Cummins guys lost motors to broken nozzles. You should ask Jason "Strokethisdmax" about failed nozzles. Curtis built his motor and would know. You could ask him too. In just about every case they were EDM'ed stock nozzles.
Best process of nozzles = EDM'd then extrude hones with balanced extrude honing machine.
Please explain me the phenomena of the 4 following diagrams, why we get less fuel with bigger holes in the beginning of the current feed ...
Specs ... 30% over
Every OEM nozzle is first EDM'd, then extrude honed. They aren't extrude honed by the same process Extrude Hone the company uses.Which is the same process probably 99% of the aftermarket injector companies use.
I never said that they use Extrude Hone machines, but I said they use balancing extrude hone machine like Sonplas. Sonplas is the mayor extrude hone machine factory for diesel nozzles production, which you can adjust the flow you want. First the machine measures the actual flow called the Bosch number which meassures the flow by 100 bar and 40 degrees Celsius. The it extrude hones exactly to the value you need, cleans the nozzle and measures again. So never go to an extrude company and say you wanna 40% over ... tell him you wanna the 1.128 @ Bosch specification!!!
here a pic:
If you open the holes with extrude honing, you don't open the holes in % (or area) you decrease the resistance radius on the inside edge. When you extrude hone the nozzle, the seats don't get destroyed and don't causes the smoke by idle. The reason you get smoke is because when you the needle opens, you get to much pressure drop on the needle tip, which we loose atomization of the fuel and causes the smoke. Also the nozzle is slower in lower fuel pressure range and causes white smoke ... I'll argue this one too....I've run injectors that flow over 2x stock without white smoke at idle in a Cummins. When you get over 3x stock they will haze a bit. So while they do have a pressure drop at the tip you can erode the seat enough to cause heavy smoke at idle. I bet if you ask anyone that has a extrude hone machine that has tried to do really large injectors they will tell you the idle smoke is heavy even on a mechanical injector where they can raise the pop off pressure. With a raised pop off pressure it changes the pressure drop in the seat.
You don't need 2x - 3x bigger nozzles ... no wonder you break the tips off!!!
Also I never heard of a CR-nozzle cracked, split or broke the tip of. This new nozzles are made from better steel and newer hardening processes.I've heard of lots of them. Several Cummins guys lost motors to broken nozzles. You should ask Jason "Strokethisdmax" about failed nozzles. Curtis built his motor and would know. You could ask him too. In just about every case they were EDM'ed stock nozzles.
Best process of nozzles = EDM'd then extrude hones with balanced extrude honing machine.
Please explain me the phenomena of the 4 following diagrams, why we get less fuel with bigger holes in the beginning of the current feed ...
Specs ... 30% over
Last edited:
BTW ... here some pics from the EDM machine I use and never goes on others ... the machine stays in a dust free room for best quality!!!
Pat, here some extrude honed from a customers a few years back ... he posted the link in 2006 ... so it will be fine ...
Extrude honed, 40% over and see the timing is also out ... If you want, post your sheet I send you with your balanced injectors I did a few years back ...
http://www.mde.cc/custom/MikeLB7/mike.pdf
super diesel
<<<< Under Pressure
Pat, here some extrude honed from a customers a few years back ... he posted the link in 2006 ... so it will be fine ...
Extrude honed, 40% over and see the timing is also out ... If you want, post your sheet I send you with your balanced injectors I did a few years back ...
http://www.mde.cc/custom/MikeLB7/mike.pdf
You can see balancing for flow is a good thing and sometimes overlooked(expecially as pressure rises). This is solid tech info.
x2 great information , the graphs say it all .
Pat, here some extrude honed from a customers a few years back ... he posted the link in 2006 ... so it will be fine ...
Extrude honed, 40% over and see the timing is also out ... If you want, post your sheet I send you with your balanced injectors I did a few years back ...
http://www.mde.cc/custom/MikeLB7/mike.pdf
I'll see if I can find them, but yes, they had the dip at idle pressure levels too. At the time, I made them idle by advancing the timing at idle to compensate, but perhaps I should have adjusted the pressure instead, and raised it. Or maybe a little of both?
On the MIKELB7 charts, the scary one is the WOT balance rate. 14% difference between cylinders????
To put that in perspective, you would being tuning the average of the cyls. Some cyls would be down 7%, others would over by 7%. Or with a 500 horse engine, 535hp fuel in some, and 465hp in others. The failure limit is the high cyl, so let's say you hurt the rods or pistons at 700hp in a balanced engine. You'd hit the failure point when you tuned it to 651hp.
Injector balance is perhaps the #1 concern when pushing against the limit.
To put that in perspective, you would being tuning the average of the cyls. Some cyls would be down 7%, others would over by 7%. Or with a 500 horse engine, 535hp fuel in some, and 465hp in others. The failure limit is the high cyl, so let's say you hurt the rods or pistons at 700hp in a balanced engine. You'd hit the failure point when you tuned it to 651hp.
Injector balance is perhaps the #1 concern when pushing against the limit.