B4001 Injector Flow Rate table help

[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 b4001 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.

[joecar]

The IFR axis is MANVAC which is BARO - MAP and not MAP.

[mr.prick]

So you are using stock 28lb injectors @ 68psi?
68 -58 = 10/68 =14.7
Increase {B4001} 14.7% from stock
Then I imagine you will need to tune all over again.

[joecar]

The IFR axis is MANVAC which is BARO - MAP and not MAP.

Ken,

MANVAC=80kPa corresponds to MAP=20kPa (assuning BARO=100kPa).

The B4001 IFR table is indexed by MANVAC... at WOT, MANVAC is 0kPa (since MAP is 100kPa).

[joecar]

See my other comments: showthread.php?p=98072#post98072

[joecar]

Ken,

If you have STOCK injectors...

Can you adjust your fuel presure regulator to 58 psi...?

If you can, that would be great because then all the other injector tables (derived by GM engineers to suit your stock Z06 injectors) would then be correct...

If not, then even tho the IFR table can be recalculated, those other injector tables may not be correct anymore.

[mr.prick]

Are the offsets dependent on FP or the impedance of the injector?

[kwhiteside]

I got the number off them, 12561462, they are the stock 28lb injectors. According to my Prosport gauge hooked to the end of the fuel rail, I'm pushing 68-70psi fuel pressure instead of 58.

Is that high psi so unusual that I should question the gauge setup, or trust the gauge and alter my b4001, then redo my AutoVE tune? Keep in mind one of the main problems identified in my track day log was that actual afr was richer then commanded.

[mr.prick]

Be sure of your FP,
I had a mechanical gauge on the fuel rail and it read 10psi higher than actual.
What fuel pump are you running, how did you up the FP?

[kwhiteside]

I did not up the fuel pressure. I bought the car a year ago. Recently hooked up AFR and Fuel pressure gauges to the apillar pod as I was thinking about running some nitrous. It is a prosport gauge that has a sender on the end of the fuel rail with an fittings then wires to the gauge.

http://www.maperformance.com/prospor...rformance.html