Time for a New Look at Fuel Injectors and Their characterization Data
08-01-2012, 08:53 AM
#21
Launching!
Thread Starter
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.
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.
There's lots of "sheep" out there-I'm just not one of them.
08-01-2012, 09:39 AM
#23
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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.
08-03-2012, 10:07 AM
#34
Launching!
Thread Starter
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.
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.
08-04-2012, 07:45 PM
#35
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 $$ build. I wouldn't trust -it should flow this and here's the data from a set we did awhile ago.
Are my customers going to buy them? NO
The injector data is a big thing now becaue I think the new computers and about 95% of the tuners out there have no clue how to tune them in correctly with these VVE table's. So plugging in data that is close is getting them by.
I'd be willing to say that pretty much no one here cares about emmision output since this board is about performance.
For now I'll stay with the injectors we use. When/if tuning them in becomes a problem I'll look into more expensive injectors.
From what I see and have seen- best data- pay someone to flow every injector you have- huge bill, can be worth it on a big $$ 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.
08-05-2012, 11:51 AM
#36
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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.
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.
08-06-2012, 01:50 PM
#37
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.
08-07-2012, 08:09 AM
#38
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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.
