I’m considering messing with my injector pop off pressures. Iv heard of people having good results with 320 bar with the 75HP sticks. Basically I want the optimal pop pressure for my truck that is not running any tuning just the larger injectors. Part of the reason I’m pulling them is to make sure I have them installed correctly and all washers, o rings, etc are properly installed. Anyways what’s the verdict on pop pressures? 

30 minutes ago, Mopar1973Man said:

Little bit to think about. Why I'm doing what I plan on. 

 

Ok my first set of injectors from DAP was the 7 x 0.0085 SAC injectors had a nasty stalling issue hot. Try re-popping a bit higher and still was having issues stalling made it worse. Then find out it was valve lash causing the stalling issue. Re-adjusted and problem gone by this point I had then redo the injectors for 7 x 0.0085 VCO and set for typical 300 bar. The lifespan is short now the injectors are below usable pop pressure and not quite to 100k miles. I want to aim slightly higher being that even the SAC's when they test dropped an average of -5 Bar from the time built to 2k miles I put on them. I figure 320 bar and the -5 bar settling would land me in the 315 bar realm.

 

 WARNING  - This is all theory and experimental. There is no proof I'm right...

 

Another member had stalling issues with larger injectors when he popped to I think 330 or 340 bar. I believe that the stalling when hot is related to too much pop pressure and too much timing adjusted. Speaking to several places The conclusion is 1 degree of timing per 10 bar of pressure raised. so if your injector is popping at 280 and you raise it to 320 bar, your looking at 4 degrees of timing adjustment. Now that's still only 2 degrees of timing over (stock), but with a Smarty S03 set to 18* of timing your now looking at 16 or so. But the 280 bar would have been closer to 20*.

 

I believe that raising pop pressure is the way to go with larger injectors. Even DAP stated that their larger injectors are popped higher. But the questions is where does the crossover between increased pop pressure and reliability cross with stalling. I believe that the larger you go the more you can raise it without issues. Smaller injectors will not see the same benefits as larger injectors will because of the pressure required to atomize the fuel is greater.

So far my tables I have show 100's at 320, 150's at 330 and 200's will be fine at 340bar. But I don't have much for information about anything lower.

Here's how my pop theory works. When you have a larger injector set to a lower pop pressure(be it time age mileage etc), your advancing the timing and that allows for more time for combustion. However when you raise your pop pressure your also shortening the duration. The amount of fuel being delivered is less, but it is now at a higher velocity. Your changing the mechanical timing on the motor. Similar to adjusting the timing on a P pump and raising the pop to compensate. When you raise your pop pressure your looking at shortening duration, and the center of the duration is still the same, but instead of injection happening over say 10 degrees of crank timing, your looking at maybe 6 or 8 degrees. Shortening the duration raises cylinder pressure and smoke control. But that is where the mechanical offset advantages ends' and you need a programmer capable of adjusting timing to compensate for the raised pop pressure, a good example will be looking at the P pump with adjusted timing and higher pop pressure.



 WARNING  I should also clarify that my stalling issues are also only in D range, not manual 1, I believe that I may have a valve body issue. Something that I'm working on getting to the bottom of. But I believe that one can safely pop 100's to 320 bar (mine are 322 to be exact), and you should see no issues. After they settle in they will be in the 310 range, and I'm hoping to get about 30,000 miles out of them before getting them readjusted.


EDIT: I should clarify that when it comes to smoke control and the Smarty S03 that I should mention that changing the revo settings ie lvl 3-5-7-9 changes how quickly the timing locks on the smarty at 18*. The quicker you hit that timing changes based on the pop pressure. So in theory smoke control on the smarty can be achieved with better tuning at raising pop pressures. But this is just how I've concluded in my mind. But raising the pop pressure did make a huge effect as my smarty is now almost smoke free.

 

EDIT2: Fixed some wording, and added more information.

Edited November 28, 20186 yr by pepsi71ocean

And here I thought buying a cummins truck, all you do is fill it up with fuel and drive it and they will run forever without pulling injectors every year.... 

But seriously injectors should last at least 100k without needed adjusting. My 150s are slightly hazy now and not as clean as they were when I first installed them, I'm guessing pop pressure is settling. I asked dap to set them at 320, I'm now curious where they are. It could be colder weather and treated fuel, I guess I'll know in spring. Still happy with power and performance. 

@Marcus2000monster

Are those 75s vco or sac?

 

I ran 100hp vcos and they were clean and powerful. Then tried 100hp sacs and they were laggy and smokey.

39 minutes ago, CTcummins24V said:

@Marcus2000monster

Are those 75s vco or sac?

 

I ran 100hp vcos and they were clean and powerful. Then tried 100hp sacs and they were laggy and smokey.

 

Don't say that I might order +100 HP nozzles... 

7 x .010 VCO period  done never anything smallre for a vp

1 hour ago, Mopar1973Man said:

 

Don't say that I might order +100 HP nozzles... 

 

I'm at sea level, but my .0085's won't smoke at all even with starting percentage at %110 and using wiretap. Not all injectors are alike!

3 hours ago, CTcummins24V said:

@Marcus2000monster

Are those 75s vco or sac?

 

I ran 100hp vcos and they were clean and powerful. Then tried 100hp sacs and they were laggy and smokey.

Sac

4 hours ago, Me78569 said:

7 x .010 VCO period  done never anything smallre for a vp

That's what I  got, thanks to you and few others. All I can say is I should of done that long ago.

12 hours ago, Dieselfuture said:

And here I thought buying a cummins truck, all you do is fill it up with fuel and drive it and they will run forever without pulling injectors every year.... 

But seriously injectors should last at least 100k without needed adjusting. My 150s are slightly hazy now and not as clean as they were when I first installed them, I'm guessing pop pressure is settling. I asked dap to set them at 320, I'm now curious where they are. It could be colder weather and treated fuel, I guess I'll know in spring. Still happy with power and performance. 

       

 

Yea somehow I didn't think that I would get away with that hahaha

8 hours ago, pepsi71ocean said:

Yea somehow I didn't think that I would get away with that hahaha

What's crazy is I just talked to a guy last night that drives a Toyota Tundra. He's on his second one. First one was 02, he traded it in with 375k on it. Second one is 14 he still drives today, has 335k. Biggest issue he had, was a wheel bearing on his first one. Rest of the maintenance was tires, set of brakes, some tune up, minor stuff. Even said on the first one he never changed timing belt and then the second one he's not planning on doing it, because it has a chain. He's kind of got a mind of his own but I guess it's been working for him. The truck he drives now looks almost new on the outside, he did say windshield is getting pitted pretty bad and his thinking about replacing it.

I had an 01 Tundra for a while and really enjoyed driving it versus my 00 F-150 I had before. Tundra has definitely been on my mind before, especially when I get frustrated with my Dodge ha ha. I do realize that it probably won't go as many miles as Cummins, but for someone that doesn't need to pull much and put a million miles they're a great truck. Although I believe I heard of someone putting a million miles on the tundra before.

Yup Toyota makes a good motor. 

20 hours ago, CTcummins24V said:

@Marcus2000monster

Are those 75s vco or sac?

 

I ran 100hp vcos and they were clean and powerful. Then tried 100hp sacs and they were laggy and smokey.

You’ve got me thinking hard now. I’m willing to run a bigger injector thts not laggy or Smokey. Are RV275s vco? If not I may have a set of 50s built with vco nozzles on my old bodies. I don’t think I want 75s again though. 

RV275 are ISB stock injectors for the RV series engine. Yes, they are VCO. 

 

You are better off getting a tuner before considering playing with injectors. Even RV275 are going to be smokey and laggy because of the lack of timing to fit the injectors. This was common back in the days before Quadzilla. There is no way to increase fueling without smoke when you are without a tuner. 

 

Jus the tuner alone will jump you forward +180 HP that is clean compared to a mere +40 HP of RV275 injectors that will be still smokey because of lack of tuning.

20 hours ago, CTcummins24V said:

@Marcus2000monster

Are those 75s vco or sac?

 

I ran 100hp vcos and they were clean and powerful. Then tried 100hp sacs and they were laggy and smokey.

You’ve got me thinking hard now. I’m willing to run a bigger injector thts not laggy or Smokey. Are RV275s vco? If not I may have a set of 50s built with vco nozzles on my old bodies. I don’t think I want 75s again though. 

6 minutes ago, Mopar1973Man said:

RV275 are ISB stock injectors for the RV series engine. Yes, they are VCO. 

 

You are better off getting a tuner before considering playing with injectors. Even RV275 are going to be smokey and laggy because of the lack of timing to fit the injectors. This was common back in the days before Quadzilla. There is no way to increase fueling without smoke when you are without a tuner. 

 

Jus the tuner alone will jump you forward +180 HP that is clean compared to a mere +40 HP of RV275 injectors that will be still smokey because of lack of tuning.

Thank you Mike. I’m definitely going to either rebuild my stock sticks or go with RVs and grab an XZT. 

20 minutes ago, Marcus2000monster said:

You’ve got me thinking hard now. I’m willing to run a bigger injector thts not laggy or Smokey. Are RV275s vco? If not I may have a set of 50s built with vco nozzles on my old bodies. I don’t think I want 75s again though. 

Thank you Mike. I’m definitely going to either rebuild my stock sticks or go with RVs and grab an XZT. 

 

If you go with a quad you can go bigger and dial back, much easier hen on my smarty s03.  Although high pop pressure will work. it seems to me that smoke and lag go up as pop pressure falls off.. Like for me at 280 bar my 100's were worn Mike and I were discussing his on the phone last night.

Comparing notes with @pepsi71ocean my injectors are about the same stages as his +100HP and getting low in the pop pressures. 

1 minute ago, Mopar1973Man said:

Comparing notes with @pepsi71ocean my injectors are about the same stages as his +100HP and getting low in the pop pressures. 

 

I expected my pop pressure o go longer then 30,000 miles from 300 bar to 280. But if I was to do it over again, I would get the 100's again, but have DAP pop them to 320-325 and after they settle in they should be around 310-315..

 

Stock at 300 bar, I think they settled to 290 quickly after adjusting,. then dropped another 10 bar over 20,000 miles or so. Even so this should be considered a maintenance item, @Mopar1973Man what does BOSCH say is the mileage interval for popping stock injectors?

I know @dieselautopower has that same book and he could answer the specs.

I’m wondering if the pop pressures have fallen in mine. Only 6k miles on them. They’re a a chance one or so could be popping low.

2 hours ago, Dieselfuture said:

What's crazy is I just talked to a guy last night that drives a Toyota Tundra. He's on his second one. First one was 02, he traded it in with 375k on it. Second one is 14 he still drives today, has 335k. Biggest issue he had, was a wheel bearing on his first one. Rest of the maintenance was tires, set of brakes, some tune up, minor stuff. Even said on the first one he never changed timing belt and then the second one he's not planning on doing it, because it has a chain. He's kind of got a mind of his own but I guess it's been working for him. The truck he drives now looks almost new on the outside, he did say windshield is getting pitted pretty bad and his thinking about replacing it.

I had an 01 Tundra for a while and really enjoyed driving it versus my 00 F-150 I had before. Tundra has definitely been on my mind before, especially when I get frustrated with my Dodge ha ha. I do realize that it probably won't go as many miles as Cummins, but for someone that doesn't need to pull much and put a million miles they're a great truck. Although I believe I heard of someone putting a million miles on the tundra before.

I can definitely relate. My first brand new truck was a 2006 Tundra. Had it for seven years and sold it for $10k less than what I paid for it. Had 22,000 miles when I sold it and still had the original battery. Only was a dealer for a ball joint recall. I know 22k is not 375k, but I sure do miss that truck.