HP Tuners GM Gen V VVE question

Hi I'm trying to tune the closed loop fueling on a gm gen v controller and I'm confused as to what the numbers in the vve table mean. All the tables are zero'd out accept for manifold switch open (indicating that's the only one used) however the actual numbers on the table make no sense. I've got engine RPM on the row and manifold pressure ratio on the column but the numbers in my table range from 638 top left to 1,932 bottom right. What are these? I expected to see units of equivalence ratio or perhaps spark advance on the VVE table but is that thinking wrong? Nothing is labeled at the top of the page and there's no description given. These numbers could be anything from cylinder airmass to dynamic airflow in some un disclosed units for all I know.

Side bar, when in HP Scanner I'm able to log the PID's for both intake and exhaust cams, however when in the VVE table it just asks for one of each. Does the VVE table in the editor only use the first intake and exhaust cams? Or is it averaging both?

I'm hoping somebody familiar with HP Tuners knows what this is, thanks

Johnathan,

Sorry for the delay, I've been at Pikes Peak Hill Climb with a race car all week and just catching up.

As you've noticed you only have one table populated, which is normal on vehicles without manifold runner control or DOD.

The axes being engine speed and MAP/Baro are relatively typical of a VE table because speed density models are based on engine speed and air pressure (along with temperature). Sometimes the pressure axis for a VE table is just MAP, but MAP/Baro gives a bit more accurate account of pressure in and out of the engine into the atmosphere.

In terms of the z data values, in the colored portion of the table, as the name implies this is related to GM's Virtual VE model, so these values are not engine volumetric efficiency percentages. That said, while the values may not look familiar, they do impact calculated engine efficiency in a similar way. Increasing z data values will result in higher calculated airflow, reducing z data values will result in reduced calculated airflow, just like a typical VE table.

Be sure you've forced speed density mode by disabling the MAF while tuning the VVE system.

Great question on the cam angles. Ideally both banks are phasing in unison, and both sides are always right on target, but in practice they're not quite that perfect. Especially during transients, one side may lag behind the other a little, or both may be off target briefly. That said, I don't suggest adjusting the VVE system or any VE system, based on transient behavior. If you only use data from steady state operation and act based on it, generally cams will be right on target, so whether a table is based on target position or actual position, your work will be valid.

I hope that helps get you going and resolve your concerns, but let us know how it goes.

Thanks so much Mike that helps a TON! I was already starting to play around with the idea that increasing and decreasing the Z values in some capacity has to correlate to VE but hearing that confirmation makes me feel way better about playing with it. I guess now it's just a matter of trial and error in determining how much does what. Thank you for clarifying about the cam angles as well. I hope you had a good time at Pikes peak that sounds awesome!

Awesome glad to hear it!

Thank you, Pikes Peak was great. We broke the record my customer wanted, almost all my friend's teams also made it to the top, and seeing the Block family carry on the tradition with Lia and Lucy was really special. It's always a long hard week, but well worth it.