Injector theory
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Injector theory
Ok you all know I have the Hmax stage II's, and I want to say the nozzles are oversized to size 12. . . from a standard of 10, or maybe even 8. Either way, they are huge, and I have the option of downsizing them. They smoke a ton right now, which is fun, but the economy has taken a dump and its too hard to keep it from smoking when I don't want it to. I'm thinking that downsizing the nozzles to the correct size might actually help with power. Why I'm thinking that is because I would think the fuel pressure in the injector with go up, along with atomization because of the smaller holes. If you can get 100 horse on stock injectors, then I would think you wouldn't need way bigger nozzles to make much more power. If you look at the stock nozzles. . . you can't see the holes, on mine, I could put a paper clip through each hole. WHat actually is done to the injectors when they are made into stage I's, or II's? Is it just nozzles? or something else too? THose who know injectors better then I, please chime in. Thanks.
Tim
Tim
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From: Rio Rico, AZ.
That's an interesting thought.
As I am writing this message I am thinking that the ratio of the intensifier piston would need to be considered as well. If the ratio is lower like some of them, for instance, a 5-1 vs the factory 7-1 then closeing the holes way down will give you a very gutless truck. You'll need the big holes to let the fuel out due to the lower pressure. Smaller holes will definatly give you better smoke control.
As I am writing this message I am thinking that the ratio of the intensifier piston would need to be considered as well. If the ratio is lower like some of them, for instance, a 5-1 vs the factory 7-1 then closeing the holes way down will give you a very gutless truck. You'll need the big holes to let the fuel out due to the lower pressure. Smaller holes will definatly give you better smoke control.
Lead Driver
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From: Columbia, MO
There have been many debates over nozzle hole size. The latest theory is the smaller holes are better because of what you say, better atomization of the fuel.
Different companies will do different things to make different stages. I think it's mostly nozzle size.
Different companies will do different things to make different stages. I think it's mostly nozzle size.
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injector diagram
So does anybody have a diagram of these injectors? Just feed me with as much information on these babies as anybody can. What the stock settings and perameters are and such. I not sure I understand you Kwik. The intensifier piston and the plunger are the same thing right? The ratio we're talking about would the the cross section area of the piston verses the nozzle area right? The higher the ratio the better. . . to an extreme of course. So if the stock is 7:1. . . . mine must be like 4:1. . . because the holes are so much bigger. What I need is some real numbers to work with, so i can do some math. I need a chemist to tell me what is the best fuel pressure to fully at efficiently atomize diesel fuel. Boy this is getting deep. . . THanks guys, keep it coming.
Tim
Tim
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From: Rio Rico, AZ.
Hutchinaugusta over on Webshots has this page on injectors.
http://rides.webshots.com/album/30760583mYdyzWSgEp
http://rides.webshots.com/album/30760583mYdyzWSgEp
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From: minneapolis, ks
how much ICP can your hpop hold at wot? Sounds like your icp could be dropping off. im running 7 hole .010 nozzles and dont have any problems with smoke. Alot of the high hp guys are running pretty large nozzles. I know that David Lott (on snow white and wifes truck) and Blowby are both running .012 nozzles on thier dt530 injectors. Mine wont be that big, im thinking 7 hole .085 on my dt530's. Your injection ratio doesnt change with hole size, thats determined internally in the injectors.
hybrid injectors are 5:1, dt530's are 6:1 and 7.3 are 7:1, this basically means that for every 1 psi you have say 7 psi of injection pressure (if running 7.3 inj). So if your ICP is dropping to 1500 psi your only getting 10500 psi of injection pressure, if you could hold 3000psi of ICP then your inj pressure would be double. Low ICP combined with big nozzles is probably why you have tons of smoke.
hybrid injectors are 5:1, dt530's are 6:1 and 7.3 are 7:1, this basically means that for every 1 psi you have say 7 psi of injection pressure (if running 7.3 inj). So if your ICP is dropping to 1500 psi your only getting 10500 psi of injection pressure, if you could hold 3000psi of ICP then your inj pressure would be double. Low ICP combined with big nozzles is probably why you have tons of smoke.
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more injection
This is some good stuff lukecline. . . My injectors are 7 hole at .012. Were downsizing them I think to .010s. But hes also doing something to the injector is self. He wouldn't tell me what, because thats hypermax's secret stuff, but he thinks it will work well. Now the nozzle needle has a spring on it, that has to be overcome with fuel pressure to open and operate. Does anybody know what the stock setting is? I had a scanner on my computer, and as far as I know, the ICP was fine. I'll find out what the numbers were, and where they were at on the RPM range. Where should the ICP be at at most RPMs? Thanks.
Tim
Tim
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From: Middle Tennessee
I believe this whole silly (pardon my expression) design is why the PSD will totally fall off of the dyno charts at about 3-5k rpms. There is simply not enough time for all of this to work, mechanically, beyond this. So does spray characteristics have the ability to overcome diesels poor combustability? Does diesel need to be fully atomized like gas? Or does it just need to be there? Any V8 should be able to rev to about double that but we cannot get there because our fuel cannot keep up. That is probably why the PSD lasts so long. Now any thoughts on this while we are "theorizing"?
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From: Columbia, MO
Originally Posted by Tenn01PSD350
I believe this whole silly (pardon my expression) design is why the PSD will totally fall off of the dyno charts at about 3-5k rpms. There is simply not enough time for all of this to work, mechanically, beyond this.
HMax most likely has some stuff going on in there to improve how fast things can move inside the injector. But, with moving parts in the injector, it does limit what can be done.
If we could get to 5k RPMs we would really be cooking with gas.
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the thing is, that is alot of weight spinning around that fast. i dont think that time for combustion is a problem, because when you are spinning the motor faster, fuel is injected several degrees sooner so it has almost the same time to burn as it does at peak torque. being that the PSD's are electronic, it is even easier to advance fuel timing once you get past the stock redline, easier than on a mechanical engine which has a mechanical timing advance.
if you could lighten the rotating assembly (dockboy mentioned that 6 pounds was taken off his crank and rods), then you have the ability to spin the motor over faster. a roller bearing valve train will also help free up some RPMs. you see these guys with 12 and 24v cummins that are strictly pulling trucks, and those with lightened bottom ends have the ability to launch off the line at 5000-6000rpm even. of course they are injecting a tad more fuel, so they don't need to burn 100% of the fuel charge to get the engine to maintain 5,000 RPM. once boost comes on, there is alot more o2 to mix with the atomized (smoke-like) diesel fuel, and it burns alot easier.
if you could lighten the rotating assembly (dockboy mentioned that 6 pounds was taken off his crank and rods), then you have the ability to spin the motor over faster. a roller bearing valve train will also help free up some RPMs. you see these guys with 12 and 24v cummins that are strictly pulling trucks, and those with lightened bottom ends have the ability to launch off the line at 5000-6000rpm even. of course they are injecting a tad more fuel, so they don't need to burn 100% of the fuel charge to get the engine to maintain 5,000 RPM. once boost comes on, there is alot more o2 to mix with the atomized (smoke-like) diesel fuel, and it burns alot easier.
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RPMs
Well I'm not super into high RPM's as anytime you spin faster. . . you decrease life. I got the high rev valve spring kit to maintain power at the top of the RPM band. . . not to exceed it. I'm just looking for the way to get the most atomized fuel into the engine. I would assume atomized is better than not. That just makes sense. I'll be getting the injectors back today. . . we'll see how it runs.
Tim
Tim