edm or extrude honed? which is better for injector tips?
- Thread starter dmaxvaz
- Start date
The factory nozzles are EDM'ed. Extrude honing can and will eat the seats out of the nozzles if you push a lot of media through them. That is why a lot of the big extrude honed nozzles smoke at idle. EDMing an existing nozzle isn't all that great either. It tends to work harden the material and crack between the holes or worse blow the end of the nozzle off. That doesn't even take into account the ability of the person running the EDM to be able to index off of the existing hole and hit it exactly to open it up. Starting with a new nozzle for EDMing is the best approach. A bonus to that is you can change the number of holes and the spray angle. Just my .02
so did you get yours edm'd or extrude honed? how big and does it smoke at idle?
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super diesel
<<<< Under Pressure
Wouldn't this make an unbalanced flow (irratic)? No thanks.
we get them EDM'ed then extrude honed...
Better flow and better atomization.
Better flow maybe. Better atomization with bigger holes. I doubt it. Read my earlier post in this thread.
I can't see the tiny amount this opens them up that it would eat the seat. Unless you mean it roughs up the seating surface and the neddle can't seat totally and you get small leak by. I've investigated some of these big injects and turned them down. The reason is, there is only about .0025 web thickness between the holes on the inside where the needle seals it off. When you go past this, there is no web left and the inside of the holes where they meet inside touch and removes material between them = less steel there to hold the tip on and when you have the inferno of combustion (most steels get real soft at 1800* meaning the hotter it gets the softer it gets from abient temps) combined with the pressure of the fuel and the hammering of the needle down on an already compromised tip, and WALLA. Look Ma, not injector tip.
I agree with Volkers Dual level tips (I worked on this for a while but didn't persue it).This way you can add more with out material compromise. He should get a feather in his hat for that design. There is one other way though to increase flow and maintain atomization with out extra pressure or an added row.
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The factory nozzles are called seat nozzles. They seal right at the holes. As anyone knows when you hone or lap something it eats away more material going into a hole and exiting a hole. So there is a taper to the entrance and exit of the hole. Being it is a seat nozzle it eats away at the seat the more you hone it. The seat/needle is polished in with a super fine powder from the factory and when you extrude hone them they use abrasive paste that is much more coarse. It seems like it is around 600 grit going off memory but it might be more coarse then that even. So while eating away at the seat material at the holes it does also roughen up the sealing surface. The more media that runs through them the worse it get's. So yes SD it does drip fuel and therefore smokes at idle.
I have tried high hole count nozzles in a Cummins and they don't make power. I'm not going to explain why but they don't. Deviating a lot from what Bosch does isn't a good idea IMO. Why do you think Bosch went to 6 hole nozzle on the LMM from a 7 hole on the LB7-LBZ? If 14 hole nozzles worked better don't you think they would use them instead of going to less holes?
I have tried high hole count nozzles in a Cummins and they don't make power. I'm not going to explain why but they don't. Deviating a lot from what Bosch does isn't a good idea IMO. Why do you think Bosch went to 6 hole nozzle on the LMM from a 7 hole on the LB7-LBZ? If 14 hole nozzles worked better don't you think they would use them instead of going to less holes?
What the engineers at Bosch told me was that it was to reduce NOS emissions on the LMM. Their race nozzles have more than 7.
super diesel
<<<< Under Pressure
Interesting. Funny thing is, I see more EDMed nozzled trucks smoking white at idle (figured it was from the bigger diesel droplets of fuel going in when it's needing alot less fuel at that RPM = unburnt fuel = white smoke). My extrudes are fine (no white smoke). I think Bosch had the idea of making an injector nozzle that flowed efficently at 300-360hp (and for emissions sake like Pat said). I'm sure they wern't thinking of making a nozzle for the guys that would be pushing this motor to the very brink (100% more fuel flow wasn't needed from the factory). Why are the dodges using bigger nozzles?
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Basically what I was trying to say previously is that not all EDM nozzles are created equal. Punching the holes out bigger in existing nozzles rarely creates a good quality hole. I have seen nozzles made this way and you can visually see that the holes were egg shaped. When a nozzle is EDM'ed it has a internal burr as well. If they aren't cleaned they wont seat correctly. Bosch doesn't use Extrude Hone to clean their nozzles after EDMing them.
From my experience the higher the number of holes the more torque the motor makes but less peak hp. I've used from 5-14 hole nozzles and some with multiple spray angles on the same nozzle. The Cummins factory nozzles are 5 holes in the '04.5 and up trucks and 8 holes in the '03-'04 trucks (they changed the number of injection events from 2 to 3, the spray angle, and the bowl design). The 98.5-02 trucks were 7 holes. I don't have near the experience with injectors in the Dmax but I doubt it's any different than the Cummins as the newer (98.5 and up) trucks have injectors centered over the bowl just like a Dmax.
I'd be really surprised if Bosch used more than 8 holes in their race nozzles.
From my experience the higher the number of holes the more torque the motor makes but less peak hp. I've used from 5-14 hole nozzles and some with multiple spray angles on the same nozzle. The Cummins factory nozzles are 5 holes in the '04.5 and up trucks and 8 holes in the '03-'04 trucks (they changed the number of injection events from 2 to 3, the spray angle, and the bowl design). The 98.5-02 trucks were 7 holes. I don't have near the experience with injectors in the Dmax but I doubt it's any different than the Cummins as the newer (98.5 and up) trucks have injectors centered over the bowl just like a Dmax.
I'd be really surprised if Bosch used more than 8 holes in their race nozzles.
yeah, but does he do this anymore? i called him the other day and he told me he is giving skiing lessons and he will call me back that night- never happened
Sorry about this
... I'm preparing the last few days for my job interview (top secret ,also for the new company we formed called "Atomized Engineering LLC"; is with me and Curtis Halvorson (DPR) which we provide a complete new stand alone controller for the Duaramax and Cummins. With this new controller we have more possibilities in tuning and functions, more user friendly, cheaper as the Bosch controller and the adaption for the engine is easier ... sorry again I'm just busy and yes, I give ski lesson for my balance beside to sit the whole day on the desk ... I still do some special nozzles also I do the extrude honing one's and I'm working close with a company in Michigan who does my extruded once ...
The special ones takes about 3 month with special equipment, also I can do form blanks which is really pricy
Every OEM nozzle is first EDM'd, then extrude honed. 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 ...
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.
Best process of nozzles = EDM'd then extrude hones with balanced extrude honing machine.
super diesel
<<<< Under Pressure
Volker (MDE) said it best. The thing about EDMing is it leaves a rough surface that needs to be polished afterward no matter how fine the setting (I've had to do it plenty). And the finer the setting, the more trodes you go through. So this make sense. Punch the hole (EDM) then extrude to smooth and polish the rough out and help with the flow.
Volker. Maybe you can comment on the atomization drop as hole size gets bigger and pressure doesn't increase = blacksmoke from incompleat combustion? Is my thinking way off here? Glad to see you teaming up with Curtis. Sould be some interesting stuff coming from that camp.
Volker. Maybe you can comment on the atomization drop as hole size gets bigger and pressure doesn't increase = blacksmoke from incompleat combustion? Is my thinking way off here? Glad to see you teaming up with Curtis. Sould be some interesting stuff coming from that camp.
I will comment this tomorrow ... I will be going to an interview right now for the biggest diesel engine manufacture in USA ... wish me luck, I need it!!!