Detuning large injector nozzles - How to pick injector size for upgrades!

[TyCorr]

One thing Jay said in post 1 was "More efficient burn = lower exhaust gas temperatures (EGT)"

If this is true which common sense would point in that direction then larger nozzles typically would be more effecient as they show lower EGTs cruising and pulling a load. However these larger nozzles have lower atomization and therefore should be more ineffecient =hotter egts? There are a few different processes for manufacturing larger nozzles of different sizes. There are also many different suppliers of nozzles. The manufacturing process and quality control likely varies a bit from manufacture to manufacture.

If the tune suffers from poor atomization it isnt the nozzle its using an icp value that is meant for a tiny injector that will run right just about anywhere in the spectrum hence the godawful heat,smoke, and lack of power in injectors fitted with tiny nozzles.

Ill come to a common ground for the threads sake. On nozzle not injectors. 80% nozzles are good. On a 238cc hybrid. The injector that should be pushed if people dont want stock remans. It uses that oh so wonderful 80% nozzle that is not getting credit for making all those tiny a codes "run good for most uses". Tune for the nozzle. The difference here would be the 238 would make the power the 175 thinks its going to without melting holes in your pistons. And it wouldnt require much more than a stock truck versus 10 grand worth of mods to make 425hp.

No i dont have a dyno sheet that was 5 or 6 years ago.

 

[KCTurbos]

I just explained CLEARLY as to why this is impossible. It's not rocket science.

According to your "logic" nothing is testable... there are to many variables with ANYTHING. Give me ANY scenario and I will poke holes it... just as you have tried. Nothing will produce a perfect test, NOTHING. But I can tell you that if you get as close as possible, then you can learn from the results.

You are correct. It is not rocket science. If you do the test you will see the results... but it is apparent that some people would rather not see the results. That's ok. But don't act like this is not a test that is possible.

 

[KCTurbos]

One thing Jay said in post 1 was "More efficient burn = lower exhaust gas temperatures (EGT)"

If this is true which common sense would point in that direction then larger nozzles typically would be more effecient as they show lower EGTs cruising and pulling a load. However these larger nozzles have lower atomization and therefore should be more ineffecient =hotter egts? There are a few different processes for manufacturing larger nozzles of different sizes. There are also many different suppliers of nozzles. The manufacturing process and quality control likely varies a bit from manufacture to manufacture.

First of all... As was said many pages back. Efficiency is a relative term. It means different things to different people in different scenarios.

I understand what Jay was getting at, and I agree with his logic. Better atomization results in cooler egts. But... cooler egts is not always a good thing in the turbo diesel world.

I personally don't try to keep my EGT's down in all scenarios. Saying lower egt's is always more efficient is wrong.

When racing down the track I actually shoot for about 1500egts because that is where you are going to drive the turbo the hardest. You are not driving the turbo as hard at 1200egts. Turbos thrive off of EGTs.

A Smaller A/R housing tends to run a little hotter in some scenarios? But that is by design. To more efficiently spool the turbo.

VGT turbos tend to run slightly higher egts... because it is actually using the vanes to create excess pressure, which creates more heat, which spools the turbo faster.





The other part of the equation is there is an "optimum" window to dump fuel. Running longer PW can create more power vs running a shorter PW with the same fuel. You need to catch the piston going back down the other side to most efficiently produce tq. Just like riding a bike and pedaling a bike. The downside is the later in the stroke you spray your fuel... the higher your egts.


So... does cooler egts always = more efficient. NO... But I understand what you are saying.

 

[superpsd]

I understand all of that hotter air has more velocity. However no one wants to be at 1500° pulling a load up a long hill. That tends to break and melt things and overall reduces engine life, injector cups crack etc... I'm not saying larger nozzles are for everyone however they can be dialed back. Will there be a compromise ...yes. Will it idle, sound, run, put down the torque like a stock truck. Nope but it can be streetable with just a little work. Want it to really work. Make sure your purchasing a quality set of injectors, make sure all sensors are fresh and hpop system is healthy and good tuning will make it all happen.

 

[CurtisF]

According to your "logic" nothing is testable... there are to many variables with ANYTHING. Give me ANY scenario and I will poke holes it... just as you have tried. Nothing will produce a perfect test, NOTHING. But I can tell you that if you get as close as possible, then you can learn from the results.

You are correct. It is not rocket science. If you do the test you will see the results... but it is apparent that some people would rather not see the results. That's ok. But don't act like this is not a test that is possible.

I'm just pointing out that you keep offering an impossible test that is clearly going to be one-sided and biased.

 

[KCTurbos]

I understand all of that hotter air has more velocity. However no one wants to be at 1500° pulling a load up a long hill. That tends to break and melt things and overall reduces engine life, injector cups crack etc... I'm not saying larger nozzles are for everyone however they can be dialed back. Will there be a compromise ...yes. Will it idle, sound, run, put down the torque like a stock truck. Nope but it can be streetable with just a little work. Want it to really work. Make sure your purchasing a quality set of injectors, make sure all sensors are fresh and hpop system is healthy and good tuning will make it all happen.

Wow... you guys are tough.

Who is suggesting to pull a hill at 1500egts? Do you have to grasp at straws so hard to find something to argue about? Wow :fustrate:


Cant we just agree that there are pluses and minuses to each injector nozzle size?

 

[KCTurbos]

I'm just pointing out that you keep offering an impossible test that is clearly going to be one-sided and biased.

It is not an impossible test. It is a very simple test.


Just because you might not like the results does not make it one sided and biased.


Use the same truck. Take any injector, make sure it is high quality. Run any tunes you want... live tune it yourself. Simply swap nozzles on the same truck, same day, same dyno, same injectors. BAM! There goes all the mystical rocket science. :doh:

 

[TyCorr]

Wow... you guys are tough.

Who is suggesting to pull a hill at 1500egts? Do you have to grasp at straws so hard to find something to argue about? Wow :fustrate:


Cant we just agree that there are pluses and minuses to each injector nozzle size?

We already do agree that there are pluses and minuses.

You are now frustrated as we were in the beginning.

The perspective on this topic has now come round full circle.

 

[CurtisF]

It is not an impossible test. It is a very simple test.


Just because you might not like the results does not make it one sided and biased.


Use the same truck. Take any injector, make sure it is high quality. Run any tunes you want... live tune it yourself. Simply swap nozzles on the same truck, same day, same dyno, same injectors. BAM! There goes all the mystical rocket science. :doh:

It is impossible, because you seem to think tuning small nozzles is just like tuning larger nozzles.

The tuning factor alone would be a far greater contributor to your testing variance than the differences in nozzles.

 

[CurtisF]

We already do agree that there are pluses and minuses.

You are now frustrated as we were in the beginning.

The perspective on this topic has now come round full circle.

Agreed.

There's really no debate that small vs large nozzles spray differently, atomize differently, etc. Of course we understand that will have an impact on how the fuel burns, emissions, etc.

To what degree? I think some of it has been blown a bit out of proportion.

 

[TyCorr]

Im gonna say this once. Having run 175/80s and 250/200s in the exact same truck with all the exact same mods having only changed tuning (duh) to run the hybrids (not one set but two by very different builders) i can say even the crappy first set that were a nightmare to get to idle were better in every aspect of comparison than the 175/80s. Every. My new ones? Forget it! These new injectors are fire.

Everyone compares the maximum output and says "see, this is _____" (insert adjective).

A dyno is a tool. It is used to effect change or measure them. It isnt the absolute. The litmus paper. Were it we'd not ask for tracktimes to validate a suggestion from a dyno. When the true test comes out, the track, the ability of any combination of parts to accelerate a set amount of mass through space is stripped of bs and corrections and whatnots. In these cases, on our discussed platform, the hybrid wins every scenario dreamt up.

 

[KCTurbos]

Im gonna say this once. Having run 175/80s and 250/200s in the exact same truck with all the exact same mods having only changed tuning (duh) to run the hybrids (not one set but two by very different builders) i can say even the crappy first set that were a nightmare to get to idle were better in every aspect of comparison than the 175/80s. Every. My new ones? Forget it! These new injectors are fire.

Everyone compares the maximum output and says "see, this is _____" (insert adjective).

A dyno is a tool. It is used to effect change or measure them. It isnt the absolute. The litmus paper. Were it we'd not ask for tracktimes to validate a suggestion from a dyno. When the true test comes out, the track, the ability of any combination of parts to accelerate a set amount of mass through space is stripped of bs and corrections and whatnots. In these cases, on our discussed platform, the hybrid wins every scenario dreamt up.

Too bad you did not just switch nozzles. You are comparing 2 completely different injector sizes and types. Hard to say that it was only the nozzles that made the difference. In fact... you could have had something wrong with the first set.

Track times are only good for WOT top end power

Dyno's are much better tools to measure spool up, where you make your peak power, where power falls off, etc.

 

[KCTurbos]

It is impossible, because you seem to think tuning small nozzles is just like tuning larger nozzles.

The tuning factor alone would be a far greater contributor to your testing variance than the differences in nozzles.

Impossible? LOL. You seriously make me laugh. By your "logic" NOTHING is testable in ANY application. I am really sitting here laughing.

Spend all the tuning time you want... or don't. I venture to say the results will still be the same.

 

[superpsd]

RA Dyno is a great tool however the ultimate test is out in the wild. Stop and go traffic, idling, different climates, different alltitudes, different loads. And many have ran these nozzle out in the real world and been very happy and some haven't. Tuning is critical as had been said many times now to making a larger nozzle run well and maintain drivability. Many of us use our trucks in different ways.

I think most of agree that larger nozzles are a compromise however I think some of us disagree that a larger nozzle can't be detuned or tuned to maintain driveability and reliability. I am happy with larger nozzles and I use my truck on and off road everyday and do mild towing. I have tested the truck out at sea levels and elevations as high as 5000 so far. I'm also not done improving my setup as well. A stock fuel pump and turbo leave a lot of room for improvemt but are surprisingly clean and driveable as is.

***I didn't mean to add the thumbs down that was an accident***

 

[KCTurbos]

Dyno is a great tool however the ultimate test is out in the wild. Stop and go traffic, idling, different climates, different alltitudes, different loads. And many have ran these nozzle out in thevenvoroment and been very happy and some haven't.

The ultimate test is the road. I agree 100%. No one spends all day on a dyno. Eventually the truck has to hit the road.

BUT... from all the testing I have done. I always do dyno and road test. It is cool to see the DYNO 100% match the driving characteristics found when driving the truck.

 

[cjfarm111]

Hotrod bring those big nozzles up to 9000 and see how they do. I'm not calling you out out I'm just curious as to how they would perform. I'm still learning about injectors and yours are something I haven't been around so it's intreging

 

[superpsd]

I will have to do that. I will have to track down some high forest roads to do so. I think 8000 is the highest any pass goes in this state. However you cant really lob on the pedal up most of the bumpy forest roads.

Edit: the highest maintained road here peaks at 7200... It a not too far from where the cabin is at. Next time I'm over that way I will take a drive.

 

[CurtisF]

The ultimate test is the road. I agree 100%. No one spends all day on a dyno. Eventually the truck has to hit the road.

BUT... from all the testing I have done. I always do dyno and road test. It is cool to see the DYNO 100% match the driving characteristics found when driving the truck.

Yeah, because I always drive like a dyno........ baby it up to a certain speed and then floor it for 8 seconds.

100% driving characteristics yo!!!

 

[cjfarm111]

We have a few high passes and paved roads around here and I do know one thing.....elevation plays a huge roll in the power/tq department.

 

[superpsd]

At 5000 elevation air pressure is roughly 12.2 psi at 9000 it is 10.5. There is one forest road I go up that is close to 6000 and I get a reading around 11.5