MAF (lb/min) vs Dyn Air (lb/min)

[PurplePiss]

I have been logging this and they do not match. Should they? If they don't, does that me the VE table is wrong?

[WS6FirebirdTA00]

dynamic is calculated by the computer based on the VE, IIRC. The MAF is calculated by the MAF, they should match. This means your VE and/or MAF is not done correctly

[PurplePiss]

My MAF might be boogered and that's why stock VE and Tim's VE haven't made it run any better. I either need to tune this specific maf or there's something wrong with it and it can't be calibrated. I assume that it is possible for a maf to not be able to be calibrated?

I have a ported 98 LS1 MAF, can I plug that in on my 05 GTO LS2 and try it if I have relocated the IAT out of the LS2 MAF?

[redhardsupra]

tuning MAF is nothing else but matching it to VE. of course, there's no point of doing so unless VE is done right, because then you're gonna end up with both of them giving you wrong info. when they differ too much tho, it's a good sign that you oughtta retune. they are usually a bit different, as one is a calculation from many components, and the other is just a simple table lookup. dynair usually looks way more choppy.

[EC_Tune]

Don't forget Chris' sponge analogy.

Dynamic airflow should be the same as MAF in steady state. If not, retuning is necessary. During transients the Dynamic airflow moves more in short duration to compensate.

I created a PID to calculate MAF Error% vs dynamic airflow.

EC

[PurplePiss]

So I need to be at steady cruise to really tell if they are close? Is WOT a transient situation? Its purely VE at that point and not looking at the maf correct?

[EC_Tune]

Above 4000 RPM it's all MAF, below 4000, it's a mix of VE & MAF.

[ninobrn99]

Don't forget Chris' sponge analogy.

Dynamic airflow should be the same as MAF in steady state. If not, retuning is necessary. During transients the Dynamic airflow moves more in short duration to compensate.

I created a PID to calculate MAF Error% vs dynamic airflow.

EC

do u have a formula you can post?

[EC_Tune]

I need to dig it off my laptop @ work. But yes I will post it.
basically its:
100*(Dynamic Airflow-MAF Airflow)/MAF Airflow.

[SideStep]

SWEET info.... and good recommendation for Dynamic Air vs. MAF error %

[EC_Tune]

100*([pid.2320]-[sens.40])/[sens.40]

[ninobrn99]

thanks!

[PurplePiss]

EC, what do you do with this formula?

[EC_Tune]

I was playing around with it just to see what happens during transitions. The dynamic airflow definitely moves faster than MAF.