E38 Injector Data from Fuel Injector Clinic

I'm attempting to tune a family member's 2007 Z06 which was tuned by a shop that built the engine but could not get the driveability to a good place. The shop originally installed larger injectors but did not have data on them so I have purchased a set from Fuel Injector Clinic to have a good baseline to tune from.

I haven't been able to find any other posts regarding this, so maybe I'm just too dumb for this but I have a few questions about the data, both what is on their website and what comes with set which pertains directly to the injectors I have.

1. Flow vs. Pressure - is the table description in the downloaded data from FIC. I believe this corresponds to table B4001 - Injector Flow Base in the tune. My concern however is that the OEM data in B4001 only changes in the top half of the pressure table and the maximium increase over the lowest pressure is 4%. The data table provided by FIC increases at every pressure (almost linearly) to a max of 59% over the lowest pressure. Does that seem reasonable? How does a 60lb. injector flow 38 lbs./hr. at 128kPa and flow 85 lbs./hr. at 640kPa but the OEM injector only flow 4% more between lowest and highest pressures?

2. My injectors' average flow rate is 561 cc/min (within 1.6% across all 8), yet the design flow was 540 cc/min. I assume that the data provided by FIC was set at 540 cc/min, so should I scale the flow up higher to match the average of the injectors I actually have?

3. What do I do with the injector offset data provided for my injectors? The set has an average offset of .969 ms at 3 bar and 13.5V. The data that came with the set also shows the offset value at 8, 10, 12, 14 and 16 volts respectively however, I can't find any table that looks at ms with respect to flow rate and voltage unless it's B1210. If it is B1210, I'm not even remotely understanding what I would update the FIC data to with respect to my provided data. Any ideas?

Thanks in advance!

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Originally Posted by spedracr93

1. Flow vs. Pressure - is the table description in the downloaded data from FIC. I believe this corresponds to table B4001 - Injector Flow Base in the tune.

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Correct.

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Originally Posted by spedracr93

My concern however is that the OEM data in B4001 only changes in the top half of the pressure table and the maximium increase over the lowest pressure is 4%. The data table provided by FIC increases at every pressure (almost linearly) to a max of 59% over the lowest pressure. Does that seem reasonable?

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Yes.

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Originally Posted by spedracr93

How does a 60lb. injector flow 38 lbs./hr. at 128kPa and flow 85 lbs./hr. at 640kPa but the OEM injector only flow 4% more between lowest and highest pressures?

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This table is a pressure *DELTA*... and the OEM data flat-lines the low part of the table because a naturally aspirated engine doesn't use that part of the table.

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Originally Posted by spedracr93

2. My injectors' average flow rate is 561 cc/min (within 1.6% across all 8), yet the design flow was 540 cc/min. I assume that the data provided by FIC was set at 540 cc/min, so should I scale the flow up higher to match the average of the injectors I actually have?

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Actual flow of injectors changes when you change the fuel rail pressure. If your injector data is flow rated at 3bar and your actual fuel rail pressure is 4 bar, then the actual flow you get will be more than the rated flow because of the higher fuel pressure.

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Originally Posted by spedracr93

3. What do I do with the injector offset data provided for my injectors? The set has an average offset of .969 ms at 3 bar and 13.5V. The data that came with the set also shows the offset value at 8, 10, 12, 14 and 16 volts respectively however, I can't find any table that looks at ms with respect to flow rate and voltage unless it's B1210. If it is B1210, I'm not even remotely understanding what I would update the FIC data to with respect to my provided data. Any ideas?

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Yes, it's B1210 provided your B1209 is set to "Vacuum".

You have to use the values provided and interpolate for missing values.

Thanks for the response. Your statement about the NA engine never seeing anything out of that range makes sense. When I look at the slope of the OEM data that did change, it's very similar to the slope of the FIC data in that range. I appreciate the education.

To interpolate the data points across each voltage, I multiplied each MAP value by the percent change at 4 bar. To fill in the gaps, I multiplied each MAP value by half of the percent change between each voltage given. For the table data outside the voltage range given, I just multiplied by the same percentage as the lowest and highest, knowing that the likelihood of ever operating in that voltage range is basically moot. The graph ended up with a similar shape to the factory graph. Seem plausible?

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Originally Posted by statesman

Actual flow of injectors changes when you change the fuel rail pressure. If your injector data is flow rated at 3bar and your actual fuel rail pressure is 4 bar, then the actual flow you get will be more than the rated flow because of the higher fuel pressure.

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I'm still confused on how to update the generic data provided by FIC with the data provided specifically to my injectors for the Injector Flow Base {B4001} table. The FIC website makes 2 points which are throwing me for a loop:
1. All values listed in the tables attached assume you are running the OE GM 58psi system when applicable. You are NOT required to adjust any of the provided data because of our policy to list flow sizes at 43.5psi when advertising our injectors for sale.
2. Please realize that the values in the tables are carefully chosen from data for a median set. What that means is that we will have tested a large group of injectors (usually 50 or more) and then picked a set in the middle of that group, then tested that complete set through the range of pressures and voltages listed in the OE GM tables and then populated the attached tables based on the average values of that median set of injectors.

The design flow (advertised flow) of the injectors I have is 540 cc/min. The average flow of my injectors is 561 cc/min. Both of those values are measured at 3 bar. The generic table data provided by FIC shows fuel flow at approximately 3.04 bar to be 58.62 lb/hr which equates to 615.51 cc/min. By my thinking, why isn't it closer to 540 cc/min for the generic data and I interpolate to get it closer to the actual which was the 561 cc/min? If they chose data correlating to a median set of 540 cc/min injectors that produced a 615.51 cc/min data point, does that mean that my set is lower than their average 540 cc/min flow by that much? Should they be calling it a 540 cc/min injector if that is the case?:confused:

The 4 bar data points are just as different. The generic FIC data says 67.25 lb/hr which is 706.13 cc/min but my injector data set says the 4 bar flow is 648 cc/min, putting my set 9% below average.

I suppose what I'm having trouble wrapping my head around is my set is said to flow 4% more than the design flow (advertised flow) yet the generic data set is 14% more than the design flow, so I actually need to decrease the table data to match my injectors. I'm guessing it really is that simple, but I'm just looking for a second opinion.

Here's an excerpt from the data provided:
Labels (kPa) Fuel Flow (lb/h) cc/min
288 57.06 599.13
304 58.62 615.51
320 60.15 631.575
336 61.63 647.115
352 63.08 662.34
368 64.50 677.25
384 65.89 691.845
400 67.25 706.125
416 68.58 720.09
432 69.89 733.845
448 71.17 747.285
464 72.43 760.515
480 73.67 773.535

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Originally Posted by spedracr93

I suppose what I'm having trouble wrapping my head around is my set is said to flow 4% more than the design flow (advertised flow) yet the generic data set is 14% more than the design flow, so I actually need to decrease the table data to match my injectors. I'm guessing it really is that simple, but I'm just looking for a second opinion.

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Second opinion is that you're doing your head in over nothing. You can't use true values, even if you had them. Take a look at table B4001.... did you happen to notice there's an 8g/s limit for that table? 60lb injectors don't fit. You'll have to scale them to fit, so whether they flow a bit more or a bit less don't matter. The only thing that matters is that you get them to fit into your table.

You'll have a shit of a time trying to dial in Small Pulse with those injectors. If you've got a NA engine, then make life easier for yourself and get some genuine Bosch injectors around 40lb.... they're good for over 500hp and a lot easier to dial in than what you've got now. They'll also fit into your table without scaling, so the ECM's torque calculations will still be correct (torque calculations get messed up when you scale a tune).

+1 on what statesman said.

Axis is pressure delta across injector, i.e. rail pressure minus manifold pressure.

( Note that in manifold referenced FPR system the delta is constant .)

Flowrate is proportional to squareroot of pressure delta.

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Originally Posted by statesman

Second opinion is that you're doing your head in over nothing. You can't use true values, even if you had them. Take a look at table B4001.... did you happen to notice there's an 8g/s limit for that table? 60lb injectors don't fit. You'll have to scale them to fit, so whether they flow a bit more or a bit less don't matter. The only thing that matters is that you get them to fit into your table.

You'll have a shit of a time trying to dial in Small Pulse with those injectors. If you've got a NA engine, then make life easier for yourself and get some genuine Bosch injectors around 40lb.... they're good for over 500hp and a lot easier to dial in than what you've got now. They'll also fit into your table without scaling, so the ECM's torque calculations will still be correct (torque calculations get messed up when you scale a tune).

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For anyone who may be as dumb as me in the future reading this thread, FIC advised me that the settings on their website are more than accurate enough to use without trying to modify for exact injector data. Basically, same as advised by statesman and joecar.

What will an OEM LS7 Bosch injector support? My particular application made approximately 630 at the crank. The "assemblers" of said engine originally installed some 60 lb. injectors that they didn't have the data for which is why I went the route I did. I just assumed that the duty cycle on the bosch would be too high but I don't know that for certain.

What are the specs of your engine build?

2007 Corvette Z06 LS7 7.0 liter
GM LS7 Head Castings - Port & Polish (I/E Runners & Chamber) CHE Bronze Guides, Competition Valve Job, Milled Heads - (Volume Unknown)
C5R Timing Chain
10% Underdrive ATI Balancer
Cam Motion Custom Grind 8620 Billet Core Roller Cam
232 / 248 @ 0.50
.646 / .630 (factory rockers w/trunion upgrade)
LSA 115 +4
MSD Atomic Air Force LS7 Intake Manifold
AIRAID Air Intake Tubing and Filter
Kooks SS Long Tube Headers - 1-7/8" Primaries with Cats
Factory GM Tailpipes & Mufflers

I've created a tune and scaled it by 30%. The startup doesn't seem that bad but I've got a few things that I'd like a bit of feedback on before I start shooting in the dark.

When it idles, the timing is jumping around from place to place for most of the time. If it idles long enough, it settles down but it's not that good. I'm either jumping between two different tables or my timing table is so screwy due to the scaling that the swing from one row to the next is too high. My issue with me tuning it is that I can't tell where it's pulling from to know where to start. Any thoughts?

Also, I'm thinking that I don't know how to create the correct MAPs or my calc.pids are off because the factor that my log creates is not usable. Can anybody take a look and see if either of these is incorrect? The cells populate with RPM increases like I would expect but the factor is waaaaay off and both tables (Low and High) are populating at the same time in the same place (meaning same row, regardless of the actual Hz value).

I don't have the OEM injectors anymore so if I were to swap back to get rid of the scaling, I would have to purchase a new set. I feel like I'm not that far away on this, just hoping to get a bit of guidance from some of you that actually know this stuff.

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I haven't updated to the latest software yet, so I can't view your file. I probably won't update my software for a while, so maybe someone else can have a look at your file and see if there's anything that needs correcting.

I've had good luck with the FICs even with scaling. What FIC size are you running? 660Hs?