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Pop pressure test with dyno results

Ok, so I'm about 10 months late posting this info, but after seeing a conversation regarding this topic pop up on another thread I felt it was appropriate for me to share this info. I am trying to post this during my lunch hour, but if I don't finish I will just post what is complete and finish it at my next available moment.

Background: I went to the dyno Feb 10 2017 to see what my combo was putting out. In case my signature changes in the future my combo at the time was: 2004 Optimizer with home-ported heads, +.010 gaskets, -.010 pistons (~19:1 compression), Harland Sharp 1.6:1 roller rockers, homemade passenger side tube header, CKO HX40 turbo with Turbo Lab wheels, water-to-air intercooler, 4" exhaust, Raptor 100 lift pump and an Omega Plus Moose pump making 122cc of fuel at 3500rpm and Bosch marine injectors set to 2500psi pop pressure. I have attached the dyno charts from that day. Here is a video from the cab during the run.


During the summer of 2016 I had some hot start problems. To address these I got new batteries (I already had 1/0 battery cables) and installed a Power Master starter. The batteries didn't really help much; the starter did improve the problem due to the 30 additional cranking RPM, but didn't cure the problem. Conversations with Conestoga Diesel led to the conclusion that the high pop pressure was at least contributing to, and probably causing, the hard hot start problem. So after my dyno results I thought it was a good time to try lowering the pop pressure in anticipation of the summer of 2017 plus see if there was power in lowering the pop pressure. Conversations with Conestoga and Justin from R&D IDI plus some additional reading on the interwebs indicated there was some power to be had by lowering the pop pressure - due to the pressure/volume relationship (Boyle's law). This made sense to me and I was excited to try something that would not only improve my hot starts but also get me more power! So I decided to re-pop my injectors myself since I already had a pop tester that I had purchased while trying to diagnose some previous rough running. After considering all the info I had available to me, I decided to shoot for 1750-1800psi. Yes, this is lower than most people choose for an NA IDI, let alone a turbo application, but both Conestoga and R&D choose this pressure for their injectors which are intended for turbo applications so I figured I might as well go big (or little?) and try it.....let's really make it an experiment! So I went for it. Now I will admit that I'm not 100% confident in how accurately I was able to match the injectors to each other because the gauge on my tester is air filled and tends to chatter when popping injectors. I had to take my best stab at it and see how it went. Here's a video I took to show another guy the process. Note that I am popping the injector into the atmosphere.....in the future I will be adding a reservoir to pop into so I don't coat my lungs with diesel.

I went back to the same dyno Apr 21 2017. So what were the results? My butt dyno told me that it was an improvement. Take a look at the attached dyno charts and see what you think. Even though I changed the pop pressure 700psi, there was little to no affect on the power. Any discrepancy between the runs can be attributed to testing inaccuracies and the fact that I was at the point of changeover between winter blend and summer blend fuel (btw I run Stanadyne Performance Formula to the recommended ratio in every tank of fuel). Pretty shocking results I think (oh and more proof that butt dynos lie).

I will say that when I went to the lower pressure 2 other things happened: 1. the idle is a bit rougher. I gained a dash vibration that I didn't have before and you can feel the engine shake at idle most of the time. 2. The engine has become quite cold-blooded - below 50*F it will blow white smoke, with the volume and duration increasing as the temperature decreasing. Below 30*F it runs quite rough until I load it and get some heat into the precups. This isn't really what I want in a daily driver. I intend to re-pop the injectors again.

My next step: I have a good set of non-marine Bosch injectors that came with my Optimizer. I would like to pop them to somewhere in the middle, like 2100-2200psi and see what happens. I believe right now that there is little-to-no power to be had with pop pressure changes....now there are idle quality and perhaps efficiency/mileage changes (I haven't verified), but nothing really to be had in power. When I do this test I will go to the dyno once again. I am interested to see if Marine injectors make more power or not - I have yet to see PROOF that they do.....and it sure seems that a pump that puts out the volume of fuel that mine does would surely show whether they do or not. If I put in the standard injectors at a middle pressure and again see no change in power, then I will feel pretty confident that Marines don't gain much - again, as far as POWER goes. If I do lose power, then I will re-pop the Marine injectors to the same pressure as the standard injectors and hit the dyno again. This should give pretty conclusive results. Note that before I pop next time, I will be getting a quality liquid-filled gauge so I can achieve more accurate results.

I think that's it for now. I'm interested to hear comments and if I think of more info I will be sure to add it.

All that on your lunch hour?

Overachiever.
 
Hmmmm . . . How many years did it take for this to finally register??? ;)

Congratulations on the first step of twelve :D

12v steps are not going to help! I am at 24v steps and the addiction only gets worse. 24v's are way more expensive than our 16v's... Around here the Dieselholics Anonymous meetings turn into a Tupperware party for diesel performance parts.
 
Well after 2 months of research I am officially retracting my theory that 304 nozzles are better than the 311

I'm not going to go into extreme detail on this right now. I dont want to hijack this thread more than I already have. But I posted my theory here so I will retract it here. I will at a later date post all of my research in it's own thread. But I will share this for today.

After I finally got a Bosch 304 and 311 in my hands. I put both under a microscope and measured them with a micrometer. I was shocked to find that the 311 does infact have a throttling pintle just like the 304. Actually they both have the same pilot injection profile. The only difference is the 311 has the main injection part of the pintle machined off. This allows the full cross sectional area of the orifice to flow fuel at full pintle lift. And has slightly more needle stroke. So it will flow more fuel than the 304. The reason for this is because the marine pumps use .330 plungers and need a higher flowing injector. It has nothing to do with the operating rpms of marine engines.

Back to pilot injection. Like I said both nozzles have the same profile. If you compare the 248 (6.2 long) nozzle to the 304 and 311 there is a huge difference in the pilot profile. The 304 and 311 flow more in the pilot stage than the 248. This is all for emmisions. More pilot decreases emmisions but also hurts mpg and hp. After discovering all of this Ive desided to abandon using either the 304 or 311 for my build. Instead I'm looking to modify a set of long body nozzles so I can have the pilot profile I want and be able to flow the same or more fuel volume than the 311 in the main injection event. The 248 is on my list of possible nozzles. But the long body injectors can fit nozzles from vw and Mercedes diesels as well. I have collected over 10 different nozzles to measure and compare. Again I will share more about this at a later date.
 
Well after 2 months of research I am officially retracting my theory that 304 nozzles are better than the 311

I'm not going to go into extreme detail on this right now. I dont want to hijack this thread more than I already have. But I posted my theory here so I will retract it here. I will at a later date post all of my research in it's own thread. But I will share this for today.

After I finally got a Bosch 304 and 311 in my hands. I put both under a microscope and measured them with a micrometer. I was shocked to find that the 311 does infact have a throttling pintle just like the 304. Actually they both have the same pilot injection profile. The only difference is the 311 has the main injection part of the pintle machined off. This allows the full cross sectional area of the orifice to flow fuel at full pintle lift. And has slightly more needle stroke. So it will flow more fuel than the 304. The reason for this is because the marine pumps use .330 plungers and need a higher flowing injector. It has nothing to do with the operating rpms of marine engines.

Back to pilot injection. Like I said both nozzles have the same profile. If you compare the 248 (6.2 long) nozzle to the 304 and 311 there is a huge difference in the pilot profile. The 304 and 311 flow more in the pilot stage than the 248. This is all for emmisions. More pilot decreases emmisions but also hurts mpg and hp. After discovering all of this Ive desided to abandon using either the 304 or 311 for my build. Instead I'm looking to modify a set of long body nozzles so I can have the pilot profile I want and be able to flow the same or more fuel volume than the 311 in the main injection event. The 248 is on my list of possible nozzles. But the long body injectors can fit nozzles from vw and Mercedes diesels as well. I have collected over 10 different nozzles to measure and compare. Again I will share more about this at a later date.
This is cool information, thanks for sharing so far. I look forward to seeing your future post. I've read and heard a little about the Mercedes stuff - they seem to be a lot more advanced as far as injectors and precups go. If we could start using some of their bits, that would be really cool......especially since the quality of our injector nozzles seems to be declining - I would guess that Mercedes quality stays pretty high......but that's just a guess.
 
I've got pages of notes and specs I plan on sharing with everyone. I can't believe after 35+ years no one had developed a better injector for the 6.2/6.5. I hope I can help change that. Unfortunately my truck is years away from being done. So I might have to find someone crazy enough to test out my injectors for me......

I've been looking into monarch nozzles. The euro guys seem to love them. They make nozzles for all sorts of diesels. Their latest version for the Mercedes 603 are top on my list so far.
 
I've got pages of notes and specs I plan on sharing with everyone. I can't believe after 35+ years no one had developed a better injector for the 6.2/6.5. I hope I can help change that. Unfortunately my truck is years away from being done. So I might have to find someone crazy enough to test out my injectors for me......

I've been looking into monarch nozzles. The euro guys seem to love them. They make nozzles for all sorts of diesels. Their latest version for the Mercedes 603 are top on my list so far.
I might be your huckleberry..... Ohio isn't too far away, but that probably really doesn't matter as it would make much more sense to ship things back and forth anyway - still, it would be cool to meet another performance-minded 6.5 guy in person. I have access to a dyno that I trust and would be happy to do some testing (as long as it doesn't blow my truck up!! ha).
 
I might be your huckleberry..... Ohio isn't too far away, but that probably really doesn't matter as it would make much more sense to ship things back and forth anyway - still, it would be cool to meet another performance-minded 6.5 guy in person. I have access to a dyno that I trust and would be happy to do some testing (as long as it doesn't blow my truck up!! ha).

This sounds like a fun adventure! We will have to get together and figure this whole thing out. I'm close to finishing my research. Next it will be time to get on the lathe and see if I can turn my idea into reality.

I don't see any reason it would hurt the engine. All the machine work is being done to the pintle. Although I am playing around with opening the orifice by .003".
 
How can you find the edge if you don't go over it? o_O

To be fair the surplus engines I get after entering Carnage threads have doubled in price over the past 7 years.
I hope that someday I’ll be finding that edge, but I’m not quite ready for it right now. Plus I sure hope it’s going to take more than an injector swap to get to the edge. Once I beef up my trans, I’m going to go for 400 rwhp.....and I hope that still isn’t the edge (and I believe it isn’t). I would sure like to get some extra Optimizer engines/parts in stock before I really go looking for the edge.
 
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