Injector question

[El chupacabra]

Ok been alot of talk about injectors and nozzles but how do you know what size to use? I mean is there a formula or what? How come most guys are only running 190's why not 285's or bigger even? Then how do you know what size nozzle you need on said injector? I mean injectors are too expensive to find out by trial and error.

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[wetnsloppy4x]

That's exactly the question I'm trying to get people discussing in the other thread.

 

[El chupacabra]

Kinda figured I wasn't the only one.

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[Ad8 PRODIGY]

Good thread, never was completely sure. To the best of my knowledge the nozzle has a big effect on burn rate. Different patterns for bigger shots. Feel free to correct that.

 

[windrunner408]

Well as wetnsloppy alluded to in the other thread, there is definitely a relationship between injector capacity(size) and what size nozzles to include with that injector. The problem when you get the capacity past a certain point is that you run into ICP problems unless you run some sort of hybrid injector, which I am not sure how those things are sized. Hopefully someone can shed some light on this subject. Nevertheless, the best way to figure out what size everything needs to be is going to have to be done at the most limiting PW (shortest amount of time) so the max amount of fuel can be squeezed into the combustion chamber in that time frame.

 

[El chupacabra]

Does anybody know how to choose injector size besides trial and error. I mean I would think the bigger the injector the more power you will make granted you will have to have a Turbo and fuel system big enough to support all that fuel. But there has to be a calculation or at least a good rule of thumb.


Or we can all just jump on the 190's/ p-max bandwagon just cause a few people tried it and it seams it works for them.



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[wetnsloppy4x]

Well as wetnsloppy alluded to in the other thread, there is definitely a relationship between injector capacity(size) and what size nozzles to include with that injector. The problem when you get the capacity past a certain point is that you run into ICP problems unless you run some sort of hybrid injector, which I am not sure how those things are sized. Hopefully someone can shed some light on this subject. Nevertheless, the best way to figure out what size everything needs to be is going to have to be done at the most limiting PW (shortest amount of time) so the max amount of fuel can be squeezed into the combustion chamber in that time frame.

Does anybody know how to choose injector size besides trial and error. I mean I would think the bigger the injector the more power you will make granted you will have to have a Turbo and fuel system big enough to support all that fuel. But there has to be a calculation or at least a good rule of thumb.


Or we can all just jump on the 190's/ p-max bandwagon just cause a few people tried it and it seams it works for them.



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Like Charles said in the other thread, the "formula" is common knowledge for those that have been in this game a long time. It's us relative newcommers that aren't clear on this. It's a little more of a "techie" subject that doesn't get discussed everyday like the myriad of "what tuner to run" discussions out there.

 

[windrunner408]

While there is a formula for injector size but I dont think it will really apply to vast majority of folks unless you are looking for serious power. While it may be kind of a swag to just get a set of 190/100s and a larger turbo, there are proven setups out there that have certain results. So there isnt a real need to reinvent the wheel. JMO.

 

[wetnsloppy4x]

I agree completely. The physical requirements to make power don't change. The technology tends to improve over time, but the basic requirements to make power don't change. You still need "x" amount of air, and "y" amount of fuel in "z" amount of time to make "xxx" amount of power.

 

[bigdirty]

Sub'd

 

[El chupacabra]

Still no real answer. I want to know what makes someone decide they need they need a certain size injectors besides trial and error or copying someone else's setup. I realize there is proven setups but the first guy to try that setup obviously didn't copy someones setup how did he come to the conclusion that he needed a particular injector? What if I want to try a different setup than everyone else. Just for example Say maybe a 68 p-max with big hybrids.


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[wetnsloppy4x]

Still no real answer. I want to know what makes someone decide they need they need a certain size injectors besides trial and error or copying someone else's setup. I realize there is proven setups but the first guy to try that setup obviously didn't copy someones setup how did he come to the conclusion that he needed a particular injector? What if I want to try a different setup than everyone else. Just for example Say maybe a 68 p-max with big hybrids.


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I can't explain the math involved to come up with the answer you are looking for El.

What I can tell you is to start with a horsepower goal. From there you can calculate the air mass is needed to reach that horsepower goal. That's the easy part. From there you need to figure out how much fuel you need to make use of that air at an acceptable A/F ratio. That's where I think the math gets a little trickier.

Check out this link from Garretts website--->http://www.turbobygarrett.com/turbobygarrett/mass_flow_rate

It will give you an idea how the air requirements are calculated. It talks about gas engines but the basics are similar. If you poke around I think there might be some info on how to factor in fuel as well. I don't have time to dig for it right now but I think it might be there somewhere.

 

[MorganY]

Most guys don't have enough air for 285s

 

[constantfix]

Most guys don't have enough air for 285s

Which leads into my point: budget

What kind of budget are you on? (not specifically you op, but in general)

I'm not going to sit here and say I know what it takes to run 285's (just using an example), but I would imagine it would be compounds and a big pile of benjamins or a real sick hookup with still a decent pile of benjamins.

I've read it before, here and elsewhere. A lot of times someone's budget will dictate what setup they go with.

Example: you can do all of your own work and get good pricing on parts. That person can afford to play around with different configurations.

You can only do basics (me) and have a set budget, well then you look into proven, well documented setups.

Just a lot of variables, IMO to answer the question....unless I totally missed it

 

[MorganY]

Which leads into my point: budget

What kind of budget are you on? (not specifically you op, but in general)

I'm not going to sit here and say I know what it takes to run 285's (just using an example), but I would imagine it would be compounds and a big pile of benjamins or a real sick hookup with still a decent pile of benjamins.

I've read it before, here and elsewhere. A lot of times someone's budget will dictate what setup they go with.

Example: you can do all of your own work and get good pricing on parts. That person can afford to play around with different configurations.

You can only do basics (me) and have a set budget, well then you look into proven, well documented setups.

Just a lot of variables, IMO to answer the question....unless I totally missed it

You are correct. For me, budget dictates setup. To run 285s...you would need a very good fuel system, built transmission, compounds, traction bars would be nice, head studs, possibly a valve train, intercooler. And the price of the injectors themselves. You may want to think of a bottom end build too.. Quite a bit of money.

 

[wetnsloppy4x]

You guys are absolutely right about the budget. However I think OP's question is more geared towards the theory of selecting the right amount of fuel for a given amount of air.

I guess I assumed the supporting mods were a given for the purposes of this discussion. No doubt, once you try to pass that 500-550 hp mark, things start getting REALLY expensive.

 

[Breaking Habits]

You are correct. For me, budget dictates setup. To run 285s...you would need a very good fuel system, built transmission, compounds, traction bars would be nice, head studs, possibly a valve train, intercooler. And the price of the injectors themselves. You may want to think of a bottom end build too.. Quite a bit of money.

I wouldnt necessarily say you'd need compounds for 285s in all honesty. A good friend of mine matched 285 hybrids with a billet 66/74 and the truck ran like a mother.. Brentos (hes on here)

When it comes to the 68mm Powermax. Anything from a 180-205 has been used by our customers. A 68mm Powermax and 205's made just shy of 620 on Scheids dyno fwiw.

Brentos is currently running 285's and a 68mm Powermax.. but its a dedicated puller for the most part.

Id be more than willing to share what we've had the most luck with.. but there are so many variables, and in all honesty, fwiw, my opinion of the most important variable lies in whose doing your tuning.

Take it for what its worth I guess

 

[El chupacabra]

Most guys don't have enough air for 285s

That's my point what size of injector requires what size of Turbo and how did you come to that conclusion.

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[El chupacabra]

You guys are absolutely right about the budget. However I think OP's question is more geared towards the theory of selecting the right amount of fuel for a given amount of air.

I guess I assumed the supporting mods were a given for the purposes of this discussion. No doubt, once you try to pass that 500-550 hp mark, things start getting REALLY expensive.

You hit the nail on the head that's what my question is.


I just think that people all assume you need twins and all that to run big sticks. I mean its a given that you need a fuel system that's gonna keep up and a tranny that's gonna take the power and hell headstuds are a must but do you really need twins jarred just proved it billet 66 with 285's RCD 68 with 285's. Can it be streetable with proper tuning?
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[Beast6.0]

That would depend on the intended use of the truck and that individuals definition of streetable. Then talking to a tuner about selecting hard parts, that when combined, he/she can tune to meet the individuals expectations. There are so many variables, take a 366 for example, there are at least 4 readily avaiable (more overall) different turbine wheels and a huge range of T3 and T4 turbine housings, which gives you a lot of different variations of just the hot side of one of the chargers available. If you can get some one to help you who has been around 6.0's a long time, they can steer you toward what works for each given truck application. But if not, just start digging, all you need to know is in these, and a few of the other forums pages.

Hope you find what you need,
:toast: