I just finished using EFILive autoVE (running the car in speed density and tuning against a wideband). Man, the car ran so crisp and responded to throttle so quickly. Why does putting the same VE table back into my MAF tune now feel so sluggish?

The car felt great in SD mode but feels blah in MAF.

 

Now you need to rescale the MAF table with your LC-1 with the trims off. Create a Map similar to the VE ben only based on the MAF o/p freqs vs rpm with the lc-1 as the data. See EFI Lives forum for the actual map.

 

Yup, the MAF and the VE table aren't aligned, so with the MAF enabled the filtered airflow values make the car feel slug-ish and slower.

 

g*K/x = VE in a MAF system. Basically the VE table is Air Ahead Prediction. GM does this to ensure that the MAF does not oversample or undersample creating transient fueling issues. The correct term for a GM VE table in a late modle 95 Up MAF system is Dyna Air. Go back to stock tables and start working the lean zones with the it set in open loop. a VE table is a bit of a moving target however becuase the vaules in the table will be affected by incoming Airflow.

 

Also dont forget when tuning that the reading from your WB O2 will be 5 samples or so behind the rest. So while you are trying to make small transistions while driving the O2 readings are delayed campared to Commanded AFR due to the gases having to go down the exhaust pipe.
I'm trying to work on something in Excel to account for the late WB02 readings, realign and create a VE modifier. I'm also going to take into account that the amount of samples its delayed may depend on RPM.

 

Good point, this behaviour becomes very evident when employing the Road Runner. With the RR you can get into the rythem of it.

 

Hi guys,

As per Doc's advice I found the map to apply BEN to MAF on EFILive. It wasn't setup for my MAF or for my LC1 but once I saw what those guys were doing I was able to transpose it to my car.

Once I rescaled the MAF according to that data (which was much easier to get than the VE data) the car felt great again.

 

Cool beans man, glad to hear you figured it out.

 

Is your MAF ported and descreened ???