A 175cc injector will flow 175cc worth of fuel, a 190cc injector will flow 190cc worth of fuel no matter what nozzle.

Nozzle size determines how fast the body will empty.

 

So will 190s w/ stock nozzles be faster then 175s/ 100%

Or only in the low end power I assume!




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I'm wondering the same thing. Maybe asked differently... is the % calculated more for how you'll be running the truck, I.E. Drag racing where the sticks have less time to refill without HP fuel pump vs. DD where this isn't as much concern Running down the highway?

During strip racing where you have a huge Turbo providing large amounts of air, are you more concerned with getting as much fuel as possible an into the cylinders as fast as possible?


D

 

I've always wondered what those numbers meant as well. Maybe we can get some performance guys in on this thread and answer our questions.

 

You'll never get an injector builder putting 100% nozzles on a 155cc and 175cc injector because there will be no performance gain by going to that big of a nozzle. Actually it'll hurt ya more than anything because it'll be hard to tune. A large nozzle like that on a small cc injector will have low pulse width where you'd want to be increasing it. So that's why injector builders will only put either 50% or 75% nozzles on the smaller injectors to keep the pulse width up and make it easy for the tuner to tune the truck for the larger injectors.

 

So what would be the bet injectors to get for someone that currently has a stock turbo but plans on getting a larger one in the future. Can I get big injectors and have them tuned for my stock turbo and then retuned for a larger turbo when I get one?

No towing, solely for the best performance gain.


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I ran my 190/75's with my stock turbo for nealy 2 years with no issues what so ever. You can have some fuel pulled so that it wont be too hot or smokey. I know there has been some with 190/100's with stock turbo and have been good. Just have some fuel pulled. I definitly wouldn't go any larger than a 190cc injector tho. My 190/75's and the 64/71/70 non vgt i'm runnin now are great with each other. Not too much smoke at all and the fuel is maxed out in my race tune Eric told me.

 

I have a question related to nozzle size. I understand the whole percent larger than stock, and which ones empty faster etc. It seems to be proven, that a larger nozzle size will make more power (190/100s make more power than 190/75s everything else equal). Because diesels are designed to run way lean from the optimum air fuel ratio of 14.7 ish, wouldn't having a longer pulse width, so a slower emptying injector, cause more of the fuel to contact more air particles for a more complete burn, and more consistent force on the piston equalling more power? Kinda like with rifle rounds, the faster rounds use a slower burning powder.

It seems that this apparently isn't the case, but why is that? If having more pulse width would yield more power, wouldn't having a smaller nozzle size make that possible?

Just thinking out loud

 

From what I have read and picked up from talking with various people about injector sizes and nozzle sizes, it appears that the size/configuration of the injector is such that it will allow a certain amount of fuel to be injected into the combustion chamber at the right time (which gets shorter and shorter as rpms increase) to make the most power. Basically this means sure you can run a 190cc injector with a stock nozzle and it will put more fuel into the cylinder at low rpms. That is because there is more time available to leave the injector pulsed longer than say when above 3500 or even 3000 rpms. At this speed the engine is spinning much faster and there isnt enough time available to leave the injector pulsed therefore a larger nozzle would be required to realize all the available fuel in the larger bodied injector.

I guess I would look at it this way. If the injector body size is increased, then the nozzle must also be increased (I would presume relatively proportional to the increase in body size over the stock injector). If anyone has to have a formula that predicts nozzle size, I would say take [(new injector size-stock injector size)/stock injector size]*2.4*100%= nozzle size for new injector. It isnt perfect but its close and seems to correlate with what guys are running or think folks should run. It basically puts 30% nozzles on 155s, 75% nozzles on 175s, 100% nozzles on 190s, 125% nozzles on 205s, and 150% nozzles on 225s. I really think once you get above 225cc anyways you are going to be looking at a hybrid injector. Does this mean you cant run other size nozzles than these? Of course not but I think most will agree that 75% nozzles are optimum for 175s and 100% nozzles are optimum for 190s and I have seen 155s offered with both 30% nozzles and 50% nozzles. This would also allude to larger than 100% nozzles being needed to realize the full capacity of injectors that are larger than 190cc. These are just my opinions and things I have gathered from reading and talking with various folks about our injectors.

 

You sir, know your injectors!! This is the info we all needed!

 

So why would Warren offer 155's with stock much less any larger injector with stock nozzles?

I just purchased 155's with stock thinking I'm upgrading but it sounds as if I've made a waste of money.

I can check with Warren to see if they in fact did put 35% noz's since it would be futile to run them with stockers.

D

 

I wouldn't say that. You will see a differnce with 155's with stock nozzles. Where you won't see a diiference (or at least a smaller difference) is when the engine is turning high RPM's (3K+)


Re-read the first part of windrunner's post. He doea a pretty good job explaining why :thumb:

 

Exactly. The reason for the stock nozzle option is offer a lower price option for guys wanting to run new injectors in their rigs. There are plenty of guys running stock nozzles on larger bodied injectors and they all say they notice more low end power but it does curtail in the upper rpm range. The real cost with larger injectors is in the nozzles, hence why stock nozzles are offered as an option.

 

I would say that that is exactly why 100% nozzled 190s make more power than 75% nozzled 190s. You are correct in your line of thinking (at least it is how I percieve it to be) that nozzle sizes only really come into play for making the most power at the higher rpm ranges. In the lower or mid rpm ranges there wouldnt be a huge difference at all.

 

I did some more thinking about the power bands for different nozzle sizes (while I am "working" lol). I have a theory that with all other factors equal, I would think that slightly smaller nozzles would allow for a wider, flatter powerband. I think more power at lower rpm but then not as high of a peak horsepower. The reasoning: the smaller nozzle would allow for greater pulse width, when the engine was spinning slow enough, so you would get a better mixture of air and fuel so more complete combustion and lower EGTs. At higher rpm, the larger nozzle's appility to empty the injectors faster would make it able to attain higher peak horsepower.

This is my theory, does it make sense to you guys?
... maybe I think too much lol

 

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Seems like all great info but I'm curious if it does where does the trucks purpose I.E.- DD use, racing, or towing come into play when deciding injector size?

 

Well truck use comes into play with available turbo options to support larger injectors. Right now the 6.0 (IMO) is kind of limited in turbo options that will allow for over 500 streetable/dd injector/turbo options. There are options but I mean let's face it. Right now we have the powermax and that can get you right at or just above 500hp but it is smokey and fu*king hot at those levels. There is of course RCD's 68mm Powermax (and Elite's Powermax SSX and HO which are relatively the same thing as the 68) which seems like it is great streetable option so far. I am following this one closely. I am just not sure how much power can be made for towing with these turbos but time will tell. Then you have the non-VGT crowd but their streetability with high HP is still debateable IMO. There are guys who are running very streetable 500+hp rigs but as to what extent they can be used for towing is still up in the air. With non-VGT you have either a 62 or 64mm (at max for any towing) and 66+ for street/drag racing and if you want to tow at greater than 500hp, you'll need two turbos for that. I guess there are turbos that are out there for our 6.0s but I am just not sure to what extent the applicability is for our motors. Pretty much though, as of right now and unless you go with compounds, towing is out of the question with anything larger than 205s and probably even 190s. This isnt to say that tuning cant pull back enough fuel for a tow tune to be written but there is no way that all of the available fuel will be realized for towing/streetable dd use. Hope this helps.

 

It helps a little but what if your not looking for all out power but do want to improve over just getting a tuner. Like me id like to get more power but dont have the money to support a crazy amount and I use my truck to just get around and do some light towing. I was curious in changing my injectors to help lower end power but not affect my use of the truck

 

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Yeah I see what you are syaing. I just think, and Idk if it is true, but with a larger nozzle you are limited to how long your pulse width can be, because even if you program for a long PW, once the injector body empties the injection cycle is over.. With a slightly smaller nozzle, the injector doesn't empty as quickly, so you could sustain a longer PW, and you could advance your timing at low rpm to something like 20* ahead of TDC, and still be injecting fuel thoughout the powerstroke. Meaning more low end power, in theory.
This is all just a theory of course, there is pretty much no way to test it short of dynoing a truck, then pulling the injectors and changing nozzles. Definitely not worth the effort lol
I better stop thinking about this before I hurt my head :rofl::rofl:

 

Well the down side to increasing timing is raised cylinder pressures. With the right size nozzles, minimal timing is required throughout the entire rpm range thus allowing full fueling without the raised cylinder pressures associated with increased timing. Basically what I am trying to get at (and have been trying to get at) is that what seems to be the best situation is most fueling at the right time in the pistons' travel without increasing PW unnecessarily to allow for the same amount of fuel from smaller nozzles and thus higher pressures.

 

So I have a question. Would I be Better off with 75% or 100% nozzles on my 190's. I'm trying to wrap my head around. How it works with oversized nozzles. Say cruising down the highway. Is it using more fuel because of the nozzles, or is it detuned to flow the same amount as a stick nozzle injector. Since its not using any more power to move down the road. Does that make any sense :hehe:


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I dont know all the ins and outs of tuning but I am fairly certain that the amount of an injector is injecting is based on % throttle and rpms (hence how much PW is available). The right tuning should not require a certain injector to inject any more fuel to drive down the road than any other injector. Again though, it all comes down to tuning.

 

Thanks for the knowledge.

 

2 year old bump of good info...

 

dose any1 know where I can flow test my injectors? they had work done to them but I don't know there cc flow

 

Contact Rykan Holder of Holder's Diesel down in Florida. He will get you squared away