Merlin

Hey, I was just curious if anyone knows if HPT calculates the dynamic airflow (lb/min) or if it is calculated by the VCM and just aquired by HPT. I was also wondering what parameters it uses to calculate this value. I am assuming it uses the Ideal Gas Law with pressure from the MAP senor, volume from the VE tables, temperature from the IAT sensor and rpm for the time. Mass and the gas constant I would guess are rather obvious but I was curious about the other variables. I am working on calibrating my MAF and just wanted to know where the mass airflow measurements are coming from. Anyone help me out here? Thanks

jimmyblue

iTrader: (11)

Dynamic airflow and dynamic cylinder air are a
mix of speed density and MAF airflow measurements
(varying in proportions w/ RPM) with further smoothing
done to settle down the jumpy readings. We know
only a little about the source blending and nothing
much at all about the post-processing (with probable
exceptions in the tuning software companies' gurus).

P Mack

iTrader: (6)

What ^he said, and yes the speed density part is based on the ideal gas law with ve, IAT, and MAP. Look here for more detail on how they're blended http://www.hptuners.com/forum/YaBB.p...num=1078851555

Merlin

Ok, thanks guys, I just wanted to make sure I wasn't calibrating the MAF based totally on what the MAF itself is telling me as that would be rather pointless. However, after reading that HPT forum page, it seems that the method of logging dynamic air vs MAF frequency to tune the MAF might not be that accurate if the dynamic air data that we are logging is tainted by input from the MAF - unless, of course, when you disable the MAF the VCM uses a pure SD calc to output the dynamic air data. Anyone know if we get a pure SD calc for dynamic air when we disable the MAF (set fail frequency to 0)?

Thanks again for the help

MNR-0

As I understand it, Dynamic Air is filtered MAF, via the Dynamic Airflow parameters. It removes the spikes a MAF sees and smooths it out.