kwhiteside

My Actual AFR is running richer than commanded during serious track days and I'm trying to figure out my tune.

The EFILive guys gave me a list of things to check, starting with the B4001 Injector Flow Rate table.

I've researched like crazy about Injectors and have some understanding now.

Stock Z06 Injectors are rated at 28lb for 58psi 4bar. The spreadsheet defaults to 43.5psi 3bar because that is how most injectors are rated when sold.

So if I input a flow rate of 28 at a rated rate of 58, but then change my actual pressure to 68 which it is, I start seeing problems. This is assuming my injectors are still stock. ( I now know there should be a part number on the side of them, I'll get that when I get my glasses to read ) So I'm racing around and my commanded AFR is based on a 58psi table when actually I'm pushing out 68psi and more fuel. This explains why I'm running richer than commanded. Now if my injectors are upgraded bigger ones, that condition would be even worse to the rich side. The pcm is sending voltage to the injectors like they are small 28lb injectors at 58psi, but if they are big 40lb injectors being hit with 68psi, they will be releasing too much fuel.

Please confirm what I'm thinking that if this IFR table is too low, I'll be running richer than commanded?

Also please explain why the table and the injector.xls spreadsheet stop at map Kpa stops at 80. When I'm speeding along, my map gets close to 100 Kpa which is off the table? Is there another place for WOT IFR?

I'm learning as fast as I can, don't laugh too hard at that last question. I hear guys talking about how the WOT settings are less computer controlled all the time, I just don't know where to look inside EFILive yet.

BLOWNBLUEZ06

So you turned your pressure from the standard 58psi to 68? If you have the capability of adjusting your fuel pressure, then why not just turn it down? If you don't have a FPR, then your stated pressure #'s are most likely off.
Most injectors are rated at 43.5psi or 3 bar.

Don't compare your MAP values to your IFR table as they are not referenced the same. For a better idea of what I'm talking about. Just consider that the 0 value on your IFR table is 100 kpa on your MAP. The MAP starts reading from maximum vacuum and goes to 100kpa at 0 vacuum. The IFR table's 0 value is 0 vacuum and 0 pressure and then moves toward vacuum values, so 80kpa on your IFR table is actually 100-80=20kpa, 50kpa on the IFR = 50kpa on the MAP value and 30kpa on the IFR = 70kpa on the MAP. Bottom line is they work inversely to each other due to the reference of one beginning the count from 0 at an atmospheric -100kpa and the other beginning the count from 0 at a true atmospheric value of 0.

Regardless of what you command, the computer makes no adjustments for you at WOT. It is important to begin with proper IFR values as well as all of the other base values, but once those values have been entered, you must adjust the MAF tables to tune the car to the actual desired AFR values. Your commanded values are a reference for the PCM based on VE and MAF tables and adjusted by the modifying tables' values such as the VE and MAF vs ECT and IAT tables.
I am an HPtuners user. If the table aren't named the same, so be it. The same rules still apply.

kwhiteside

I didn't turn my pressure up. I bought the car a year ago and have installed a prosport fuel pressure gauge. It usually reads 68-70psi. I've had it over at Vengeance Racing and they seem to think my car had been severely modified in many areas. So I'm assuming the gauge is correct and the last guy had a higher pressure fuel pump put on. I'm get a magnifier or glasses to read the part number imprinted into the injectors when i get home. I thought i could read bosch, but my eyes are getting a little fuzzy these days. If i find they aren't the originals, that will even more confirm the previous owner was going more fuel.

Whats the chances my Prosport gauge is reading wrong?

BLOWNBLUEZ06

There's a chance. You can make a cheap handheld gauge setup and use it for a comparison. 42 is a big injector for an N/A motor. Maybe used for fuel enrichment on a decent sized dry nitrous kit.

kwhiteside

My injectors are 12561462 stock 28lb z06 injectors for sure.

I'm wondering if my gauge is reading high. Everybody seems to act like the vettes should be at 58 fuel pressure and it is odd to be different.

Beer99C5

Do you have a BAP?

Stock pressure is 58 PSI, if you have a BAP or aftermaket fuel pump it could be higher.

The spreadsheet is likely redhardsupra's, it is what I used for updating my 42 # delphis (rated for 3 bar, used 58 PSI for the new values since that is are operating pressure) Worked no problem.

I would say return to the stock values. And do some logging, should be closer than what you seeing.

I would start and replace the fuel guage or run a another to compare values, as well as return the 4001 table to stock and do some logging to see if AFR falls back inline.

Gordy M

Using the IFR table from redhotsupra these are the flow rates of 28 lb injectors @ 58 running 68lbs of pressure

3.8200499 3.840365733 3.860574657 3.880678343 3.900678418 3.920576468 3.940374038 3.960072636 3.97967373 3.999178756 4.018589111 4.03790616 4.057131238 4.076265644 4.09531065 4.114267497 4.133137399

These are the IFR at the normal 58 lbs of pressure.

3.528 3.549987566 3.571839784 3.593559122 3.615147975 3.636608667 3.657943455 3.679154528 3.700244014 3.721213979 3.742066434 3.762803333 3.783426574 3.803938007 3.82433943 3.844632596 3.864819209

The above are in 5 kpa increaments of MAP. Basically your making the injectors running 8.3% richer than you tune. Also, it looks like your LTFT's are off the chart.