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Time for a New Look at Fuel Injectors and Their characterization Data

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Old 08-01-2012, 08:53 AM
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Originally Posted by eb02z06
So I guess all the cars tuned without data don't get good driveability and don't pass emissions?
There is a HUGE difference between passing a local emissions test and being federally compliant as the manufacturer of record. A simple plug in (OBDII) check or even IM240 does not come anywhere near the complexity of the FTP UDDS, HWY, US06, SC03, and Cold CO tests. When I was a calibrator at GM, the goal was to have our tailpipe emissions at 1/2 of the federal standard with 4k mile catalysts for each test. Tier II Bin 5 standards are not always a cakewalk to hit, even with a completely stock new engine. These emissions targets are the reason why it takes an entire team of calibrators about three years to release a new engine and calibration package at the OEM level. Minimizing the variables during the development process is not just a convenience, it's a necessity.

Funny I took a set of 120lb low impedance injectors, plugged them, and got a car to get good fuel economy and pass emissions on a roller with no cats.
I'll be the first to admit that we've all "done what it takes to make it run right" at some point in the performance aftermarket. It never fails to amaze me how dumb I USED TO BE. Learning more about how the control system and physical injectors actually work has been a huge advantage when it comes to making this process easier, faster, and more consistent for me though. Even at my level, I'm never done learning.

Nobody is going to get me to pay $1000 for modified set of $500 dollar injectors and tell me there "better".

There's lots of "sheep" out there-I'm just not one of them.
I think you're still mistaking me for someone who is trying to sell you injectors. I don't care where you bought your injectors. I'm just saying that the process of calibrating the engine is 1000% easier if you actually know what the injector is doing and give the PCM precise control of delivered fuel mass. You are free to continue doing it the hard way. My car runs great.
Old 08-01-2012, 09:12 AM
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all the correct data in the world wont help if you cant input the values into the tuning suite cough *HPTuners*...
Old 08-01-2012, 09:39 AM
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Originally Posted by oange ss
all the correct data in the world wont help if you cant input the values into the tuning suite cough *HPTuners*...
Just to be 100% sure... does this mean I should ditch HPTuners in favor of, say, EFI Live? I'll do it in a heart beat because I've def. had idling issues with larger injectors.
Old 08-01-2012, 10:13 AM
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Originally Posted by Somebody09
Just to be 100% sure... does this mean I should ditch HPTuners in favor of, say, EFI Live? I'll do it in a heart beat because I've def. had idling issues with larger injectors.
I have no experience with EFI Live, that would be your call


sorry for the hijack Greg
Old 08-01-2012, 01:27 PM
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Originally Posted by oange ss
all the correct data in the world wont help if you cant input the values into the tuning suite cough *HPTuners*...
Originally Posted by Somebody09
Just to be 100% sure... does this mean I should ditch HPTuners in favor of, say, EFI Live? I'll do it in a heart beat because I've def. had idling issues with larger injectors.
So are you saying you can't input the injector data in HPtuners?
Old 08-01-2012, 02:16 PM
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Originally Posted by Somebody09
Just to be 100% sure... does this mean I should ditch HPTuners in favor of, say, EFI Live? I'll do it in a heart beat because I've def. had idling issues with larger injectors.
they have the same tables.... i don't understand this statement.



what I do get is the "delivered fuel mass" that is the trick.
Old 08-01-2012, 02:26 PM
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Originally Posted by Somebody09
Just to be 100% sure... does this mean I should ditch HPTuners in favor of, say, EFI Live? I'll do it in a heart beat because I've def. had idling issues with larger injectors.
How large is large?
Old 08-01-2012, 04:01 PM
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Originally Posted by edcmat-l1
So are you saying you can't input the injector data in HPtuners?
you can, but the values input are changed. I.e. if you input .0062 into a field you might get .0804 as a final value. Something to do with the hex-dec conversion was the excuse I got. Not isolated to any one table or value field.
Old 08-01-2012, 04:08 PM
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Originally Posted by oange ss
you can, but the values input are changed. I.e. if you input .0062 into a field you might get .0804 as a final value. Something to do with the hex-dec conversion was the excuse I got. Not isolated to any one table or value field.
What OS are you working with? I have not noticed this, and I tune a few cars.
Old 08-01-2012, 04:11 PM
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Originally Posted by edcmat-l1
What OS are you working with? I have not noticed this, and I tune a few cars.
PC ? XP, also happens on my Windows 7 laptop.
Old 08-01-2012, 04:18 PM
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Originally Posted by oange ss
PC ? XP, also happens on my Windows 7 laptop.
No. What PCM OS? What are you tuning that you see that?
Old 08-01-2012, 04:26 PM
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Old 08-03-2012, 09:32 AM
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Greg (turbolx), how long does it take to do an injector, meaning full characterization and collection of data?
Old 08-03-2012, 10:07 AM
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As long as the injectors are clean and functional, data collection takes about one full day in the lab for me to get what I consider the basics of characterization. This means a complete flow curve at 13.5v for a set of eight injectors at a single pressure and a shorter series of tests at varying voltages in order to find the trendline of offset vs voltage and populate that for the same single pressure.

Adding multiple pressure breakpoints simply adds a complete repeat of the procedure, as does running more than 8 pieces. I typically test 4 injectors at a time to make sure that their flow doesn't outstrip pump capacity or rail distribution, so testing 8pcs means two sets of four. If we are trying to get data for a part number rather than just a single set of flow matched injectors, then we really should test more than 8pcs. There can be build tolerances of +/-6% for production injectors, more for aftermarket. Finding the real "average" behavior requires that we test more samples in order to make sure we get a statistically significant sample.

The going rate for engineering consultation is north of $100/hr (just like a good lawyer, accountant, doctor, etc...) so spending a full day or three on this quickly eclipses the typical cost most associate with "engine tuning." I'm not recommending that everyone has every single injector measured, as this would be prohibitively expensive. But it is certainly nice to be able to have the confidence to say that you really know exactly how much fuel is being delivered on each shot. To some race teams or injector manufacturers, this cost is literally a drop in the bucket compared to the rest of the operation. So for those guys, we try to make sure we have as much GOOD data as possible.
Old 08-04-2012, 07:45 PM
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I'll agree with Arun on alot he said.

From what I see and have seen- best data- pay someone to flow every injector you have- huge bill, can be worth it on a big $$ build. I wouldn't trust -it should flow this and here's the data from a set we did awhile ago.

Are my customers going to buy them? NO

The injector data is a big thing now becaue I think the new computers and about 95% of the tuners out there have no clue how to tune them in correctly with these VVE table's. So plugging in data that is close is getting them by.

I'd be willing to say that pretty much no one here cares about emmision output since this board is about performance.

For now I'll stay with the injectors we use. When/if tuning them in becomes a problem I'll look into more expensive injectors.
Old 08-05-2012, 11:51 AM
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Originally Posted by turbolx
As long as the injectors are clean and functional, data collection takes about one full day in the lab for me to get what I consider the basics of characterization. This means a complete flow curve at 13.5v for a set of eight injectors at a single pressure and a shorter series of tests at varying voltages in order to find the trendline of offset vs voltage and populate that for the same single pressure.

Adding multiple pressure breakpoints simply adds a complete repeat of the procedure, as does running more than 8 pieces. I typically test 4 injectors at a time to make sure that their flow doesn't outstrip pump capacity or rail distribution, so testing 8pcs means two sets of four. If we are trying to get data for a part number rather than just a single set of flow matched injectors, then we really should test more than 8pcs. There can be build tolerances of +/-6% for production injectors, more for aftermarket. Finding the real "average" behavior requires that we test more samples in order to make sure we get a statistically significant sample.

The going rate for engineering consultation is north of $100/hr (just like a good lawyer, accountant, doctor, etc...) so spending a full day or three on this quickly eclipses the typical cost most associate with "engine tuning." I'm not recommending that everyone has every single injector measured, as this would be prohibitively expensive. But it is certainly nice to be able to have the confidence to say that you really know exactly how much fuel is being delivered on each shot. To some race teams or injector manufacturers, this cost is literally a drop in the bucket compared to the rest of the operation. So for those guys, we try to make sure we have as much GOOD data as possible.
This is amazing to me. It could take days to get the data on 1 set of injectors? Makes me wonder how companies that say they flow and do this characterization to every injector do it, imo I bet they don't, until now I never had an idea how long it would take. How would we know if they did or they did not, lol. That's why I didn't go for spending 1200 for a set of injectors when I got the same injector for 500..
Old 08-06-2012, 01:50 PM
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Originally Posted by Slowhawk
The injector data is a big thing now becaue I think the new computers and about 95% of the tuners out there have no clue how to tune them in correctly with these VVE table's.
Anybody trying to calibrate injectors via the Volumetric Efficiency table (whether virtual or conventional) has no business tuning a lawnmower, let alone a closed-loop automotive engine.
Old 08-07-2012, 08:09 AM
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Oh, I have no idea if HPTuners does or doesn't ... I was only asking for clarity. I haven't tried messing with fueling on HPTuners since I got that new cable upgrade, which is probably 5+ years old now. They were 42 lb injectors and simply scaling the table didn't yield the best idling characteristics. So back to stock I went.
Old 08-07-2012, 10:46 AM
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Originally Posted by crainholio
Anybody trying to calibrate injectors via the Volumetric Efficiency table (whether virtual or conventional) has no business tuning a lawnmower, let alone a closed-loop automotive engine.
Guess I'll go tune some lawn mowers then.

You don't tune in the whole injector off VVE ***. Most tuners will throw in a injector table and call the injectors bad because they didn't tune in VVE. Get it yet? LOL
Old 08-07-2012, 11:47 AM
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Originally Posted by Slowhawk
Guess I'll go tune some lawn mowers then.
I couldn't tune a lawnmower to save my life.


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