Can we talk injector flow rating for a minute?

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-Boostjunky-

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OK, so, I know a lot of us are already aware that the aftermarket ratings of injectors are not very representative of what's actually being injected in terms of real world use. I learned this fact some years ago, and it has bothered me ever since to see people tossing around flow ratings in the 30, 40, and 50 LPM range.

I mean, let's be realistic, here. If you had injectors that injected such large quantities of fuel, you'd probably hydro-lock your motor with fuel.

More realistic figures have been claimed to be in the 1 LPM range for stock HPCR Cummins injectors, and with using 100% over injector nozzles, more like 2 LPM. That seems much more realistic, and thanks to honest companies like Exergy, we have flow data to back those figures up.

I just recently had a friend get his Duramax injectors flow tested at a local Diesel repair and performance shop (Gillette Diesel), and he came back with flow figures in the 31 LPM range, and that they were 55% over stock. He was not given a flow sheet, they didn't tell him any specifics as to balance percentages or backflow values, they just told him, "Everything looked good."

This bothers me. BADLY. No substantial data was given to back up their claim of "Everything looked good." And the fact that they rated the injectors at 31 LPM just bothered me even more.

So, I wanted to know if anyone out there has any idea how these shops are coming up with these flow ratings. I've heard that some shops test injectors with compressed air, and that this is how they come up with flow ratings in the 30+ LPM range. I asked my friend to verify that Gillette wasn't using air in their testing procedure, and they assured him that they did, in fact, use a liquid (what liquid, I don't know), and that they have a "fancy" common rail injector test stand.

How, then, are they coming up with 31 LPM? I just don't understand.

Furthermore, how does one take the data from an Exergy printout, where it shows injected quantity in mm3 at different pressure ranges and pulsewidth values, and translate it to a LPM rating?

I know that Exergy ends up usually printing out the LPM rating on the sheet, but I have seen a sheet (which I will attach) for stock injectors that only showed the mm3 values, and didn't show what the LPM rating was for said injectors.

If anybody has a formula to take the mm3 ratings to translate them into a LPM figure, that would be awesome. I suppose it would help to know what the mm3 rating was derived from in terms of how many times the injector was fired for the test, given the pressure and pulsewidth at that injector at the time of the test.

On to some data sheets:

Stock nozzles (these are the ones without a LPM rating)
stocknozzles_zps18e2e7bf.jpg


60% over injectors
60overs_zps095ab94e.jpg


105% over injectors
105overs_zpsb7f0515c.jpg


Any insight would be greatly appreciated.
 
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Some places use air instead of fuel to rate them. Some flow just the nozzle whiles others flow injector.

phone
 
I never understood how they think using air can be an accurate measurement. I know very high flowing 12v injectors are in the 5lpm range. 31lpm is not a realistic number imo at all.
 
ClamDigger4 said:
Some places use air instead of fuel to rate them. Some flow just the nozzle whiles others flow injector.

phone
Click to expand...

That, I understand. It was for this reason that I had my friend ask specifically if the shop was using air to test his injectors, or liquid. They specified that they used liquid in their test stand, and rated his injectors (which were not the shop's own injectors, they were DDP nozzles) at 31 LPM.
 
2.6 trucks run 1/3 lpm rated injectors than that at tops. 6-7lpm. Sounds like air to me.

phone
 
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Send your money to company's that can actually flow the whole injectors and provide data. You can turn this back into %over by simple comparing operating points between the modified injectors and stock.

So for the hack job tuning of factory ecu's you can use the % over to modify your injection conversion table's or in the case of stand alone you just use the actual flow numbers in mm3's.
 
Actually this is what you want: Along with the data set. It's as good as it gets.

injectorflow_zps9326c9b6.png
 
Ok, so does anybody know what pressure and pulsewidth uS is used for calculating actual flow rate of the injector in ML/min?

For example, the mm3 value at a pressure of 1600 bar and pulsewidth of 1800 uS on that chart shows it flowing about 350 mm3 per stroke.

How many strokes are there in a minute? I know that in real world situations, that is entirely dependent upon engine speed. But for testing/flow rating purposes, what pressure, duration, and how many strokes per minute are used in a standardized test?
 
Injector #1 on the 105% over set in the third graph being 2192ml/min would be 2.192lpm, this is done with the raw nozzle no needle steady state @ 100BAR and 42° celsius with viscor test fluid.
 
Smokem said:
Injector #1 on the 105% over set in the third graph being 2192ml/min would be 2.192lpm, this is done with the raw nozzle no needle steady state @ 100BAR and 42° celsius with viscor test fluid.
Click to expand...

Ah, thank you, very much. That helps to know that the LPM rating is just the nozzle.
 
Can anyone comment on how II now rates and flows their injectors with the new Bosch equipment they use?

I have BMS nozzles honed to 100% overs or "200HP", wondering if they actually are or I got taken...
 
I had 90's in mine at one time. I forget who did them, but they were tagged 29lpm. Don't even start on Flux's. But it would be great if everyone used the same scale. How weston explained it makes perfect sense though.
 
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