I have gotten a lot of different answers about flow rates and stuff for the stock stage 2 injectors. A lot of it conflicting, but there seemed to be a trend in that they arerated at 3 bar, with a flow of 42.5 and a rail pressure of 56-58.

Okay, so let's take 3bar = 43.5 psi and run the numbers with 56 and 42.5:

40.03304349 40.4818578 40.92575046 41.43761574 41.87137731 42.30069122 42.72569154 43.21624306 43.63232637 44.04447916 44.45281076 44.92450703 45.32491116 45.72180893 46.11529087 46.57015137 46.95652498 47.33974523 47.71988808 48.15959577 48.53331748 48.90418331 49.33333652 49.69823268 50.06046915 50.42010325 50.83646092 51.19064366 51.54239264 51.89175733 52.29639974 52.6407605 52.98288314

Same with 57:

40.54835415 40.99152674 41.42995902 41.93567039 42.36433277 42.78870097 43.20890153 43.6940284 44.10560461 44.51337549 44.91744469 45.3843121 45.78069489 46.17367502 46.56333863 47.01386446 47.3966211 47.7763114 48.15300792 48.58879622 48.95924181 49.32690542 49.75241245 50.1142573 50.47350815 50.83022 51.24324552 51.59463588 51.9436492 52.29033306 52.69191474 53.03370738 53.3733113

And 58:

41.05719763 41.49493604 41.92810462 42.42787885 42.85161775 43.27120733 43.68676715 44.16664546 44.57385793 44.97738377 45.37732133 45.83950521 46.23198544 46.62116169 47.00711603 47.4534288 47.83266817 48.20892432 48.58226656 49.01423845 49.3814926 49.74603553 50.16798778 50.5268566 50.88319446 51.23705415 51.64682628 51.99548927 52.34182978 52.68589361 53.08448297 53.42376411 53.76090412

Stock stage 2 files for 05 and 06 start at 40.1601 at -120 kPa Vacuum. I have seen a tune from someone else that said they "modified" their IFRs for 42 LBers and theirs match the 40.1601.

My 07 came from the dealer with stage 2. My IFR table starts at 40.9129. With this much conflicting data what do I do? Trust the dealer/factory tune or buy some lucas 42 LBers that are flow tested? I would hate to dish out the money for 60s when I rarely touch 100% IDC, but it sucks to blow $200 on more 42s that won't improve my flow. I get from everybody that IFRs are where you start, but how? Is there a way to know when your IFRs are off? Maybe that is the approach...

Any thoughts?

 

Does anybody know how to tell if your IFRs are not correct?

 

ummm nope no clue sry

 

can you check your IPW vs RPM...?

Fuel Injector Duty Cycle Calculator

I forget where I got this link, maybe WopOnTour link

 

Well, I can log my IDCs directly, but how does that tell me whether or not my IFR tables are correct? I also noticed, BTW that not only is my IFR table different from the others, but my offset tables are as well. A LOT different.

 

How are you getting this information..??

this is a 2007 stage 2 (stock) Injector flow rate vs. kpa vac
40.91291 41.36730 41.82168 42.27413 42.72657 43.14511 43.56268 44.06066 44.51698 44.90742 45.25426 45.64276 46.05936 46.44884 46.81990 47.21906 47.63663 48.01447 48.36616 48.77210 49.21486 49.60045 49.94923 50.30480 50.66617 51.01883 51.36761 51.72414 52.08551 52.41976 52.73657 53.08535 53.45545

 

Mine matches the one you just posted. Stock 05 and 06 look like this:

40.16013 40.55638 41.03305 41.42930 41.82653 42.22278 42.69945 43.09667 43.49292 43.96959 44.36584 44.76306 45.15932 45.63598 46.03321 46.42946 46.90613 47.30238 47.69960 48.09682 48.41363 48.81085 49.12766 49.44544 49.76322 50.08100 50.39780 50.79503 51.11184 51.50906 51.82684 52.06517 52.22309

I got that from Deni's tune from the HPT repository as well as an 06 "Stock stage 2" file from there as well.

The numbers that I got from the info I ran came from here:

 

I've personally measured rail pressure to be at 58psi on my car, so I've used that in my IFR calculation.

I have better results tuning the offset table by hand. Log voltage, trims (or a/f error), and map and see what the difference is between cells, that should tell you how far off your offset table is.

 

Now that sounds promising. I can log all of those things. Don't fully understand though. More info? (he asks with a small ray of hope...)

 

For offset, theres a histogram already setup, you just have to load it from the options menu. I changed my offset table to a MAP based one as its easier to work with than a vacuum based one. Just personal preference. Anyways, I log ignition voltage, MAP, and trims and use that histogram. I then take the difference between cells and multiply that into the offset table.

 

And your MAF and/or VEs won't mess with the findings?

Also, I do not see that histogram in the import menu.

 

Thats the reason I only use the difference between cells. Say all cells are between +5 and +7 error, I simply subtract 5 from all of them. If they are between, lets say +4 and -4 then you wouldn't have to subtract anything. You'll find they'll only be +-1-2% off from each other in reality.

The number that is left is the one that is your error due to your MAF calibration.

 

Cool. Thanks. So you think the IFR should be okay then and I should just concentrate on the offset table, correct?

 

Eh, I wouldn't spend too much time on either. The values you have are within 1-2% of each other. I would concentrate more on your MAF tuning, thats the most important part imo.

Heres a screenshot of that offset table you can setup. Remember mine has been converted to a MAP offset from the factory vacuum one. If you are using the vacuum offset values, change your table in the histogram to vacuum instead of map and log the pids/sensor accordingly.

 

Sweet. Thanks. This is going to be important, because I will be winding up with 60 LBers soon, I think and I do not want to just multiply everything by a percentage. I want to be able to dial stuff in right. Besides, there are almost no Chevy in my area, and I would like to become a resourse for people who need tuning in the SF bay area.

+ rep for your help.

 

No problem. With 60s you'll spend a lot of time on these different values if you want the car to run like it does with 42s. You'll notice before you have everything dialed in with 60s the car will drive completely different until you have decent values. Offset on 60s is fairly different than then one for 42s.

 

I can imagine. I think for now, I will get back to working on my VEs and MAFs and do some more reading on the IFRs and offsets and stuff, so that I can get an understanding of what they really do. I was concerned because of the data I was finding, but you helped ease my mind a bit, so I can get back to what I was doing.

By the way, IDCs that peak at 102% at 6800 RPMs aren't too big a concern are they? I can always ramp the boost down at 6700 right?

 

Yeah, you'd have to play with the desired torque settings if you have an 06 or 07 under Boost Control.

 

I was thinking just enter 95% under the boost level from 2nd gear up. No?

 

Okay, so my 60s are on the way in and I am setting up a tune that I can flash after installing them. I read the instructions for first set up injectors that ssnipes posted and I get 99% of it. The part I think I need help with is the min pulse width, short pulse limit, the adder and the offset table. with the offset table, I want to be able to know where to get the numbers for the tables to start with, then I can dial them in better by using the method explained earlier in this thread. With the others... well, everything in the quote by witt I don't get...

Thanks in advance for any help...

 

Bumpage for the all knowledgable morning crew!

 

you already know where i stand d00d

 

LOL. Yep, but when I get this info, between my fuel maps and your timing maps, we will have the baddest balts around (if you ever get around to installing those 60s!).

 

im just lazy. timing is no biggie for me. other people it is. some people on here have seen what i run for timing.

 

I have no idea when it comes to timing. You know that, you've seen my logs. Maybe, I'll have you teach me some stuff around timing once I finish getting the injector values nailed.