An interesting read on redrilled injectors

[eficalibrator]

I've been trying to make the point to the tuning community for quite some time that not all injectors are created equal. Hence, my original article on fuel injectors on my website.
(http://www.calibratedsuccess.com/Assets/Documentation/Fuel Injector Article.pdf)
Paul Yaw from Injector Dynamics finally got the time to perform the test that I knew would confirm what I already suspected about redrilling. Simply put, the idea that "you can just use the original offsets and short pulse adjust values with modified injectors" is bullcrap. Read Paul's article for the details. (http://www.injectordynamics.com/DrillbitsAndDipshits.html)

The short story is that there is indeed a very significant shift in offsets and short pulse adjust values that comes with changing the orifice plate. Get these wrong and you'll find yourself baking a lot of unnecessary changes into your MAF, VE, and idle control tables.

[GAMEOVER]

Good read...:D

[redhardsupra]

Paul and Greg, THANK YOU!

Short Pulse Fueling tables and such are there to make up for the particular physical characteristics that show up as the nonlinear portion of the injector flow. If you change the physical characteristics (I think drilling holes counts as such), wouldn't then all the numbers whos entire purpose in life is to describe these nonlinear oddities, have to change accordingly? Why is this so hard to understand?

[injectordynamics]

I don't think it is hard to understand. I think it just needs to be presented with real world data so that it is more than an abstract concept. I get frustrated sometimes because these myths still exist. Fact is, I just need to quit bitching, and get off my ass and do the work so that people can see it.

The emails coming in within hours of posting the article make it clear that people understand it now. I'm glad you liked it.

Paul Yaw
Injector Dynamics

[samh_08]

So what injector are we supposed to get if we need bigger ones? Sometimes stock ones with 'stock' data aren't big enough. Any suggestions?

Great read by the way. Your work is appreciated!

[L31Sleeper]

So what injector are we supposed to get if we need bigger ones? Sometimes stock ones with 'stock' data aren't big enough. Any suggestions?

Great read by the way. Your work is appreciated!

Um.............Injector Dynamics Of course.

[eficalibrator]

All of the Ford Racing Injectors can be used in a GM application too. I have reverse engineered the characterization data from Ford to GM units for these injectors and include that data as part of my professional training material.

The major point here is that it's OK to use new injectors. You just need to make sure you have complete data on them to avoid creating tuning errors from the start.

[joecar]

All of the Ford Racing Injectors can be used in a GM application too. I have reverse engineered the characterization data from Ford to GM units for these injectors and include that data as part of my professional training material.

The major point here is that it's OK to use new injectors. You just need to make sure you have complete data on them to avoid creating tuning errors from the start.Greg, is that data available on your DVD...?

[eficalibrator]

Greg, is that data available on your DVD...?

Yes, the data disc that comes with the "GM Tuning Beginner's Guide" DVD includes raw injector data for all of the FRPP injectors in GM table format. You may still find that some high-flow injectors require scaling to fit older PCM limits and that some PCMs also have a minimum raw pulse limit (transient fueling) that must also be reduced to allow my data to work properly. The nice thing is that Ford rates their injectors at 2.7bar of rail pressure, so running them on a GM vehicle with 4bar yields higher flow rates and supports more power.

[samh_08]

The nice thing is that Ford rates their injectors at 2.7bar of rail pressure, so running them on a GM vehicle with 4bar yields higher flow rates and supports more power.
So running a Ford injector at 4bar doesn't change anything but actual fuel flow? No adverse changes to injector data?

[joecar]

...
The nice thing is that Ford rates their injectors at 2.7bar of rail pressure, so running them on a GM vehicle with 4bar yields higher flow rates and supports more power.Greg,

In the injector data on your DVD, is rated pressure indicated being 2.7 bar...?

(i.e. is the rated pressure apparent to someone viewing the data on the DVD)...?

[ I'm asking on behalf of someone thinking of buying the DVD ]

[5.7ute]

Greg or Paul, going from that article, the offsets increase when drilled due to the change in the high slope of the injector. This being calculated by continuing the high slope down to the 0cc/min axis.
However when reading the Ford injector data article, the offset is measured from where the low slope intersects the 0cc/min axis. So in theory, the offsets when drilling have a major effect in a GM calibration which only has a defined high slope & small pulse adder, but next to none in a Ford type calibration which utilises both a high & low slope. (Which in that example the low slope was similar)Is this correct?

[injectordynamics]

Greg or Paul, going from that article, the offsets increase when drilled due to the change in the high slope of the injector. This being calculated by continuing the high slope down to the 0cc/min axis.
However when reading the Ford injector data article, the offset is measured from where the low slope intersects the 0cc/min axis. So in theory, the offsets when drilling have a major effect in a GM calibration which only has a defined high slope & small pulse adder, but next to none in a Ford type calibration which utilises both a high & low slope. (Which in that example the low slope was similar)Is this correct?

Give me a day or so, and I'll feed that same data into my Ford worksheet and put real numbers on it.

Paul Yaw
Injector Dynamics

[5.7ute]

Give me a day or so, and I'll feed that same data into my Ford worksheet and put real numbers on it.

Paul Yaw
Injector Dynamics

Thanks Paul.
Also if you could share your formula for cc/min to g/sec (petrol) it would be appreciated.

[injectordynamics]

Thanks Paul.
Also if you could share your formula for cc/min to g/sec (petrol) it would be appreciated.

It is fuel dependent. In the case of my testing, the specific gravity of the test fluid (Gasoline) is .72 grams per cc.

Paul Yaw
Injector Dynamics

[5.7ute]

It is fuel dependent. In the case of my testing, the specific gravity of the test fluid (Gasoline) is .72 grams per cc.

Paul Yaw
Injector Dynamics

Thanks, much appreciated.
Now to see if I can make a rough spreadsheet to convert the data between units.

[eficalibrator]

Greg,

In the injector data on your DVD, is rated pressure indicated being 2.7 bar...?

(i.e. is the rated pressure apparent to someone viewing the data on the DVD)...?
The data included with the DVD is presented with a nominal working pressure of 4bar. I had to do some interpolation between Ford data points to get there when I plotted the mass vs time curves (at 4 bar) in Ford units before converting to GM units. What you see on the data disc should be more or less copy and paste into a GM controller with 4bar (58psi delta) working pressure. Some ECUs have different axis breakpoints, so some interpolation for that is occasionally necessary.

[eficalibrator]

...This being calculated by continuing the high slope down to the 0cc/min axis.
However when reading the Ford injector data article, the offset is measured from where the low slope intersects the 0cc/min axis. So in theory, the offsets when drilling have a major effect in a GM calibration which only has a defined high slope & small pulse adder, but next to none in a Ford type calibration which utilises both a high & low slope. (Which in that example the low slope was similar)Is this correct?
You're on the right path here. I don't have the data to confirm that redrilled injectors are "close enough" on a Ford low slope, but I would agree that the offset error should be less than what we see on a GM-style offset. In a perfect world, I would still want to see the data since I know that the Ford low slope is really just a straight line compromise to what is really a pair of opposed curves.

[injectordynamics]

I would agree that the offset error should be less than what we see on a GM-style offset.

Even if the offset error ended up being less, it's only because the term "offset" has a different meaning in Ford speak.

GM and Ford are both describing the same thing which is the flow vs pulsewidth curve of the injector.

At the end of the day the difference between the mass of fuel you want, and the mass of fuel you get would be the same as long as both Ford and GM describe the response accurately.

In any case, I'll feed that same raw data into the Ford worksheet and get it posted.

By the end of the day if the phone will stop ringing...

Paul Yaw
Injector Dynamics

[5.7ute]

How come whenever these injector discussions come up I end up with more testing to do? :doh2:
Paul, is there any chance of getting some raw data sets from your testing to have a play with? I would like to compare what I come up with to ensure I am on the right track.
Cheers Mick

[injectordynamics]

Greg or Paul, going from that article, the offsets increase when drilled due to the change in the high slope of the injector. This being calculated by continuing the high slope down to the 0cc/min axis.
However when reading the Ford injector data article, the offset is measured from where the low slope intersects the 0cc/min axis. So in theory, the offsets when drilling have a major effect in a GM calibration which only has a defined high slope & small pulse adder, but next to none in a Ford type calibration which utilises both a high & low slope. (Which in that example the low slope was similar)Is this correct?

I fed the raw data into my Ford worksheet and added the chart and data as an addendum to the original article. (http://www.injectordynamics.com/DrillbitsAndDipshits.html)

Paul Yaw
Injector Dynamics

[5.7ute]

Thanks for adding that Paul. It certainly shows that no matter what system you are using, the offset data etc is incorrect once you drill the orifice plate.