Testing Injector Pop Pressure in the real world

[Me78569]

I did rerun the 0 -60 test this morning after fixing the boost leaks,  

 

 

Guess what I found.. nadda difference in all 3 sets to 60 lol..  close enough not to matter I guess. ( for me at least)

 

[Dieselfuture]

So what you're saying is basically higher pop (around 330-340 for 250hp injectors)  is better for starting and clears up smoke, other than that no gains in power that worth talking about. 

[Dodgeih]

1 hour ago, Dieselfuture said:

So what you're saying is basically higher pop (around 330-340 for 250hp injectors)  is better for starting and clears up smoke, other than that no gains in power that worth talking about. 

Seems like it... But honestly the dramatic lack of smoke is enough too justify the higher pop.. No real ill effects to popping at 335-345 and that should settle to the best area that we have come up with

[Me78569]

I think we are best to leave pop within what bosch specs.  297-327 bar.  I think a set of 7 x .009's might have stalling issues at 330 bar, where as a set of say 7 x .12's won't.  the cold start issues That @kzimmer and  I have had at 350 makes it a little concerning for dd use.    I do hope mine settle some and cold cold starts wont be an issue.  I cannot afford to have the truck not start at -20*f if I need it too.  

 

 

I also can't say that we have enough data to say that everyone and their brother should be running higher pop, in fact I am still quite the oposite.  If you want to run them, there may be perks, but you may run into issues.    The stock bar injectors could run as smooth with correct mods to the tune, but in doing so you would loose some offidle power.  

 

We might also find that stepping down a size in injectors is a better fit than increasing pop if the person does not care about all out power, like myself.  I am sure I would be happy with 7 x .011's at stockish bar.  

 

 

I just dont want people jumping on the "band wagon" if that makes sense.  I see perks and downfalls.  Honestly I dont know if hte normal person would even notice the difference in the 330 bar I liked so much vs the stock bar setup. 

 

I dont think we are reinventing the wheel here.   I really don't think the perks are that huge overall.   I like the reduced smoke offidle, I like the under the curve power I seem to feel.  but a lot of that may be related to my altitude as well.    A sea level you may not notice much difference.   So just consider all of that.  Power to you if you like to play with stuff, but don't think increasing pop pressure is going to cure anything.

 

 

 

 

Edited February 14, 2018 by Me78569

[dieselautopower]

34 minutes ago, Me78569 said:

I think we are best to leave pop within what bosch specs.  297-327 bar.  I think a set of 7 x .009's might have stalling issues at 330 bar, where as a set of say 7 x .12's won't.  the cold start issues That @kzimmer and  I have had at 350 makes it a little concerning for dd use.    I do hope mine settle some and cold cold starts wont be an issue.  I cannot afford to have the truck not start at -20*f if I need it too.  

 

 

I also can't say that we have enough data to say that everyone and their brother should be running higher pop, in fact I am still quite the oposite.  If you want to run them, there may be perks, but you may run into issues.    The stock bar injectors could run as smooth with correct mods to the tune, but in doing so you would loose some offidle power.  

 

We might also find that stepping down a size in injectors is a better fit than increasing pop if the person does not care about all out power, like myself.  I am sure I would be happy with 7 x .011's at stockish bar.  

 

 

I just dont want people jumping on the "band wagon" if that makes sense.  I see perks and downfalls.  Honestly I dont know if hte normal person would even notice the difference in the 330 bar I liked so much vs the stock bar setup. 

 

I dont think we are reinventing the wheel here.   I really don't think the perks are that huge overall.   I like the reduced smoke offidle, I like the under the curve power I seem to feel.  but a lot of that may be related to my altitude as well.    A sea level you may not notice much difference.   So just consider all of that.  Power to you if you like to play with stuff, but don't think increasing pop pressure is going to cure anything.

 

 

 

 

 

 

It was a fun experiment.  I am glad we could help.  

Its not harder to build a set to higher or lower pop off pressure if requested.  We plan to continue the slight raise in pressure as injectors get larger.... 305BAR for Stock to about 315BAR on the bigger sets. If someone wants a different pressure we can put it in the build notes.  

[Me78569]

the cold start issue has me confused.  I honestly think that we might be having issues with too little timing at cranking as a result of too high of pop pressure resulting in issues starting when cold cold.   

 

It seems as if you need to crank for ~20 seconds before there is enough heat in the fuel to get it to pop off.  

 

 

the 330 bar injectors didn't seem to have issues, but these 350 bar do when temps get down near 0*f

[Dodgeih]

6 minutes ago, Me78569 said:

the cold start issue has me confused.  I honestly think that we might be having issues with too little timing at cranking as a result of too high of pop pressure resulting in issues starting when cold cold.   

 

It seems as if you need to crank for ~20 seconds before there is enough heat in the fuel to get it to pop off.  

 

 

the 330 bar injectors didn't seem to have issues, but these 350 bar do when temps get down near 0*f

Mine set to 340 , for the short amount of time I wasn't have fuel leak and cam sensor issues started better than any Cummins I have ever been around.. Barely hit the key and it was running.. For fun I tried starting once at 15ºf with out waiting for grids and it hadn't ran for 13+hrs and it started instantly.. Coughed and sputtered for maybe 5 seconds before smoothing out.

[AH64ID]

Too bad you can’t advance the cranking timing based on ECT to find out,  but I think that too little timing is the best explanation. 

[Me78569]

That was my situtation as well, until temps got below ~10*f.  It was almost like a light switch honestly, very confusing.

Just now, AH64ID said:

Too bad you can’t advance the cranking timing based on ECT to find out,  but I think that too little timing is the best explanation. 

I wish I could mess with that, but sadly the quadzilla is "off" when cranking.  I honestly dont even know if the ecm commands anything during cranking or if the vp is handling that all....I kinda think the vp is in charge of that.

[trreed]

Nick I remember a time when the Quad would display 3.32* when the truck was off, and any throttle input brought the commanded timing to 8*.  Now, the timing shows 3.32* regardless of throttle input while the truck is off.  So the switch to 8* would mean the ECM was in control of cranking timing.  Not sure why it stopped commanding 8* these days though.

Edited February 15, 2018 by trreed

[Me78569]

3.32* is the timing min in the ecm.  8* is the min allowable timing for the quadzilla, which is why you seen it go from 3.32 to 8*, now the way the quadzilla takes over is different so you dont see tha tflop until after the truck is running.

[Dieselfuture]

Oh learned something new again I'm going home now, waight I'm already there .... not sure why commented.....losing my marbles I think, am I glad weekend is around a corner it will be grilling time, been way too long since I did that 

[trreed]

Good to know Nick. I’ve been wondering about that.

[Me78569]

Another day of temps below ~15* and another day of hard starts when cold.  

 

I still dont know if it is related to too little timing or the pump not able to inject at 350 bar when cold.    I am leaning towards the first though.  

 

Be warned if you go above ~340 Bar you will have issues starting when the temp gets down near 0.  It is as if a light switch is flipped.

[kzimmer]

 

On 2/19/2018 at 8:06 PM, Me78569 said:

Be warned if you go above ~340 Bar you will have issues starting when the temp gets down near 0.  It is as if a light switch is flipped.

 

See! I'm not crazy. Haha.

Edited February 21, 2018 by kzimmer

[Me78569]

19* today and it popped off easy as pie.

[BBHD]

On 2/19/2018 at 7:06 PM, Me78569 said:

Another day of temps below ~15* and another day of hard starts when cold.  

 

@Me78569 I was wondering how your truck started this morning. My overhead showed -14 coming down Monument this morning at 6am. 

[notlimah]

Ok so just got re-reading through this entire thread as I finally got bigger injectors 7x.012 (should be here today!) and they're currently set to 350 bar and based on this thread, it seems like setting them to 330 with the expectation they'll drop 10ish bar, that would keep them in the happy area for the VP as well as a good spot for that sized injectors.

 

Can someone back me up on that thought process??

[Dieselfuture]

4 minutes ago, notlimah said:

 

Can someone back me up on that thought process??

That's what I'm planning on doing some day, I just hate the fact that I have to mess with injection lines that are not currently leaking 

[kzimmer]

If you don't have any negative effects like stalling or hard cold-starting, I wouldn't be afraid to run 350. Just be aware that those are known side effects.