Idle Timing Adv question
 

Does anyone know how much timing adv flux i should expect at idle when Cammed and larger sc. Also have NW103, BG, ARH long system and headers, lower pulley. Been trying to dial in my idle and i see timing adv change by ~15 degrees while idling. I am on the positive side. I am Tuned to run by MAF only.

The TQ tables i have adjusted so far are the 4 Idle Tq tables plus the VT table. I have the car set to run at 825 in PK/Neutral and 800 in gear.

The car uses timing to trim the idle via virtual torque calcs, and a car tuned “MAF-only” will struggle to idle well with a cam.

Any idea how tough it is to dial in VE on the GenV platform? I have never tuned VE, not even on my 2012 Camaro.

I was thinking of using Zone 0-1 only. I only need it for idling.

I wonder if the big name shops tune VE in the cars they do.

It’s a pain in the rear IMO. I ended up finding a good local tuner who didn’t mind that I had done most of the tuning myself. He ended up fixing up my VVE tables (not called VE anymore). Goat Rope Garage on YouTube does a decent job of explaining it and showing how to tweak it. Just make sure you save your tune before making an adjustment... ;)

If you go on the HP Tuners forum, you’ll find most of the decent tuners are always tuning VVE too. If you’ve watched Greg Banish’s videos, he explains why it’s important. The Tuning School says you don’t need to, and they’re wrong IMO.

I agree that many tuners don't want to touch it. I am thinking if I only do zone 1 it might not be too bad.

I don't think its that hard, mainly depends on how OCD you are on how perfect you want to get it.

Use the bluecat VVE coefficients generator, the HP Tuners built in one just isn't that great and the solver in it will get really unstable between boundaries and screw up your smoothness of your table and change parts of the table you don't mean to change.

I agree 100% you have to tune VVE and get it right if you want a good idle. I also had to adjust the virtual torque table by about -20% or so in the idle regions and only on the negative and low timing tables. Before I did this it would idle at really low timing values and made the exhaust louder.

Looked at my VVe today but I set it only to run up to 1400rpm. It was appx 43% rich.

43% rich as compared to what? A wideband? the stock O2s?

Stock VVe numbers. I only did 600rpm to 1400 rpm and I had to reduce the vve table numbers 42% to get them within 3 %. Guess it's understandable with all my mods.

I don't think we can trust wideband or any O2 feedback with a cam with overlap at idle, I think fuel trims still may look stable and relatively low as well as O2 oscillation, but can we really trust what O2's are saying when the car is misfiring and combustion is not even occurring properly because the cam is so big?

Most PD blower cams have little or even zero overlap. Mine actually has negative overlap! So if factory O2 is telling you too rich at idle and you can back that up with wideband readings, I suspect you’re safe making adjustments based on that data. On a choppy NA cam, maybe it’s a different story.

^Facts