Originally posted by teamzr1:
Its hard to look at gas mileage on cold winter weather but I'd suspect the MPG will increase a bit in summer for keep in mind winter gas makeup does not give good MPG
What is the difference in the USA? Over here I think it's the same
Originally posted by teamzr1:
You might try a test of setting IFR a bit leaner across the board, as long as you do not have ping then engine will perform better and MPG will also increase
Does it mean that with positive LTFT's the engine is running light lean to stoichoimetric? And with negetive LTFT's it's light rich to stoichoiometric?
Originally posted by teamzr1:
Being you have water injection I would not expect a linear IFR table since when WI is on makes AFR about 8% richer thus IFR needs to be commanded with shorter injector pulse width when WI is on
WI turns on at 2 PSI and off at 0.5 PSI. For my particular (low boost) setup this additional enrichment happens in open loop only.
I was able to tune the IFR only in the closed loop range (20 - 90 kPa), over 90 kPa I just set it as a linear continuation of the curve.
I now have to check what happens in PE...
How does the PCM calculate the IFR under boost?
My MAP only sees 105 kPa max, the IFR goes only up to 100 kPa. Does it keep the last value @ 100 kPa? Does it extrapolate up to 105 kPa then it's linear?
I ask because there's something I don't understand:
After 105 kPa I think the PCM keeps a constant value. In reality there's less fuel flowing because of the backpressure in the intake manifold. But the PCM doesn’t notice that.
At the same time the MAF is checking for the amount of air and commands the injectors accordingly.
With constant PE vs. RPM values I should see the AFR rising proportional to the RPM (and to the boost).
In reality the AFR remains constant (that was with water alone. So the AFR wasn’t affected by the alcohol).
Why?
Something similar happens when the supercharger is disconnected: with constant PE vs. RPM values the AFR at WOT decreases at high RPM. Linearly.
Can I assume that my MAF is seeing more air than what really flows?
In NA and at WOT I see a constant MAP of about 90 kPa, so this is not something I can adjust with the IFR.
Is there some other factor that influences the AFR at WOT?
COT is disabled and the temperature is 190 – 200F. What else could it be?
Stefano
