TurboBerserker

iTrader: (1)

So I ran a little experiment to see if my VE table results mentioned in the other thread (getting 60-80% VE using the SD method) were screwy because my IFR values were too rich. Makes sense, right? VE is very low hence IFR is too rich...

Anyway, I made two runs -- one with the stock ve table and IFR of 5.44 (old value was 5.15), and another run with the stock ve and IFR of 5.75.

The first run's results are almost identical to the 5.15 setting, and the second run is closer to ideal, but still shows -10 LTFT in many areas. I cleared the LTFTs in both runs and tried to avoid boost. Why didn't the 5.75 setting make the LTFTs lean? It certainly would with the MAF plugged in.

I arrived at the 5.15 IFR by computing new inj size / old inj size * old IFR. I've also talked to about a million people who say that the 42# stubbies are around 5.2 IFR.

Thing is, at 5.15 the truck seems pretty rich (AFR gauge is 2 leds into rich). At 5.75, the AFR gauge is right at the top of stoich, but also crashes out the o2s every now and again (and I mean crashes... they go to < 10 mv). Looking at a graph of the o2s, 5.75 is really sleepy most of the time, 5.44 is kinda sleepy, and 5.15 is still a bit sleep at times.

Is there an exact formula for calculating IFR based ONLY on the injector size (and not on the old value, etc.)? I have 44# racetronix flow matched injs

monodax

I can calculate your IFR table exactly if you post your stock table along with the stock injector size and your old fuel pressure along with your new injector rating and fuel psi.

TurboBerserker

iTrader: (1)

I have a linear table, so it's pretty easy from that point.

I've been told the stock injectors are 24#s (but I think this is either incorrect or the rating at 3 bar / 43.5psi) and the pressure is 58psi (4 bar) at the rail.