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Marine Injector Mythbuster

52K views 26 replies 15 participants last post by  sshewins  
#1 · (Edited)
"Marine injectors" make 40 more hp?



Stock tip # 304
Marine tip # 311
-----------------------------------------------------------------

Stand set to 70 cc fixed using test calibration nozzles
------------------------------------------------------------
3,000 rpm
_________

311
130 bar 69 cc
142 bar 67 cc
146 bar 65 cc

304
142 bar 64.5 cc

1,600 rpm
__________

311
130 bar 41 cc
142 bar 51 cc
146 bar 46.5 cc

304
142 bar 49 cc

Conclusion: Marine injectors basically put out the same amount of fuel unless you drop the popping pressure to stock specs.

Marine injector output drops dramatically at low speed especially if you drop the pressure real low. Pressure plays a critical role with different combinations.

Atomization does not appear to be affected by the slight pressure changes. If anybody has a simple way to verify atomization please let me know.

These specs really need a graph, so somebody can jump right in and make one.

Some tests were not performed on the stock nozzles because that's not what this subject is about and it takes to long to test all the possibilities.

Myth > Busted.

Someone told me Army injectors make more power, but that might be just a myth. :)
 
#2 ·
Injector Numbers
BOSCH
New #-----------Body #----Reman----Tip-----Pressure---Application
0432217081....0430211051...NA50X...0SD248....126 bar......6.2L 1982
???????????.....0430211058...NA52X...0SD253....126 bar......6.2L Long body
0432217092....0430211054...NA51X...0SD253....126 bar......6.2L Short body
0432217229....0430211054....??????...0SD304....126 bar......6.5L N.A.
0432217251....0430211054....??????...0SD304....142 bar......6.5L Turbo
0432217255....0430211054....??????...0SD311....150 bar......6.5L TD Marine
0432217275....0430211097....??????...OSD304....126 bar......6.5L N.A.
0432217276....0430211097....NA56X...0SD304....142 bar......6.5L Turbo

"bar" is equal to 1 atmosphere - multiply 14.7psia by the number on each line to determine actual injection pressure

Delphi Injectors
6703803---6.5 T.D.
6703802---6.5 N.A.
6703801---6.2 "Van" Short fine thread
6704001---6.2 Long fine thread.

Standyne Injectors (New)
37818 10233973 6.5L T.D. same as 0432217276 6703803
38272 10233972 6.5L N.A. same as 0432217275 6703802

* Info has not been verified but is believed to be accurate till somebody proves otherwise.

Try get'n this info anywhere off the net.
 
#3 ·
Your results show that at 142 bar the marine nozzles dump more fuel than OE.

When I bought my HO injectors from Heath I was told that pop pressure was stock - only change was the nozzle.

Myth completely busted? Depends on pressure....like you said....
 
#4 ·
3.5 cc difference in output is only achieved when the pressure is changed to stock. Marine injectors are set higher than stock and output remains vertually the same. If you use factory settings for both marine and stock the difference is nothing. So myth busted.
 
#8 ·
70 cc's is the Stanadyne spec (70mm/3/stroke)

This is the max setting for the 5521 pump on the test stand with the calibrated nozzle holder assemblies designed for that specific pump. I set the pump to max setting and then recorded the results with the stock/marine injectors.

I am not prepared to do extensive testing nor do I desire to.

Point was to prove whether or not marine injectors put out enough extra fuel to produce another 40 hp. In this case it did not.
 
#6 ·
Re-graph....this time it should be right...
 

Attachments

#7 · (Edited)
A test of 80 mm^3 at 3000 RPM would be great if possible...
 
#11 ·
With really rough math, and you only add 3 mm3 of fuel extra, that would mean that you have turned a 195hp engine into a 204hp engine with that much extra fuel. That is of course dependent upon many, many variables.
 
#12 ·
Nice work DP.

In my lifetime experiences, here is what I have learned. A higher pop pressure does not cause more fuel to be added. Higher pops make a finer atomization, and also delay opening a tad (Same as advancing the ignition on a gas engine), but only to a very small degree.

Higher pop injector allows fine tuning an engine, but no way does it make buttloads of HP in itself. Going to hi pop injectors and expecting 40hp gains is like changing your spark plugs and expecting 40hp. Ain't gonna happen. Going hi pop, and adding more injection duration, and yeah... you are gonna get more hp.
 
#18 ·
Wouldnt you get more power just adding more fuel, too? Or would adding more fuel make more power with the marine injectors than it would with stock ones? Its only roughly a 60 PSI difference.... is that enough to make a difference?
 
#17 ·
DP

I’m sure everybody here appreciates your input and I’m no different, but…

I think for you to say ‘Myth Busted’, is inaccurate. What you have proved is that a Marine Injector doesn’t flow enough fuel to support the HP Claims with a factory program.

You said Stanadyne sets their stand to 70mm output. A good percentage here have aftermarket ecm’s. Reported rumors have claimed upwards of 85mm with a modified program. Would an 85mm stand show different results? I don’t know, I’m asking.

Two of the most reputable Vendors here have either said or advertised increases in HP. One has said ~25hp and the other advertised ~40hp with his ecm. Maybe not all Marine Injectors are created equal or your testing is incomplete.

Whether or not you do more testing makes no difference. You have backed up with what you have stated for a long time. I think there are more variables for it to be conclusive though.

Regardless, I've made my choice on the purchase.

Myth not completely busted...
 
#22 ·
DP
Two of the most reputable Vendors here have either said or advertised increases in HP. One has said ~25hp and the other advertised ~40hp with his ecm.
correct me if I'm wrong, if each vender is claiming the increased power with their ECM, but are specifying marine injectors, does anyone know how their ECM would do w/ OEM injectors? Sounds as if the ECM is providing a longer pulse=more fuel versus a higher pressure for more fuel...is that correct?

if one were to throw in the marine injectors with stock nozzles, you could have a bit more fuel; wouldn that make the engine run a little rich?
 
#19 ·
I don't support the 40 hp just from marine injectors in a truck.

I don't think you will see any difference from the naked eye on spray pattern comparing the 2 nozzles.

I have seen high speed camera recording of injectors and a larger nozzle orifice will flow the diesel a bit faster (all else the same). Its a small change and only a few micro seconds difference in a couple mm penetration. A guestimate of time the piston stays at TDC over a 2 degree arc of crank travel is 0.129 seconds (at 2800 rpm). So faster penetration of fuel at higher fuel rates and higher RPM probably makes a difference (maybe to economy or emissions and or power). I have always appreciated these are factory injectors from reputable manufactures and if it makes a difference to them then there is probably a difference.

Do they change speed or rate of temp rise in cylinder ???? I think Marine nozzles help for thier application - steadier higher fuel rates and higher sustained RPM's.
 
#21 ·
How much to "tweak" my pump???? :rolleyes:
 
#24 ·
I own a number of heavy trucks and the mechanical cats always dyno quite a bit higher when the injectors are worn out. There is probably some variation dependant on the amount of wear in the fuel pump as well, but I don't see how a worn pump can flow a bunch more fuel. Seems like it would leak back more and pump less if anything. Anyway, a 4-1/4 3406 with half a million miles on the injectors and trailing a cloud of smoke can usually run with the big dogs! I don't notice anything like the difference in my trucks with electronic engines. Don't know if this is helpful to the discussion or not, but just what I have observed. Speaking of smoke, the Heath goodies I just installed on my pickup didn't give me a cheap 325 horsepower, but I don't see smoke anymore, ever, which is sure nice. And it does go a lot quicker.
 
#25 · (Edited)
That's kind of my arguement bearmtnmartin. I propose any HP gain may be from the combustion event timing differences. I THINK its probably at the upper RPM's and not any real usable HP for a truck engine. I have read issues with truck idling with marine injectors so MAYBE a HP/Torque dyno curve would show less low rpm power and better mid and upper rpm ranges power.

I guess I see the injectors as somewhat of a restriction as if they were not any restriction the flow would be measured same as the pump output at 70cc's. But they are under.

If someone can explain the test more fully and it might be clearer. I take it you run the IP fixture for a set number of strokes or time and measure the output diesel actual vs setting??? And if so I can see the volumetric differences being very little but penetration rate and or combustion a/effect still being measurable in HP/Torque, emissions, or other.
 
#27 ·
Isn't the 5068 pump rated at 100cm? I think its a bit more than the latest version's rating, but exactly how much, I dunno