VE Table and VEAL

[NigeT]

Hi all,

I have been running VEAL most times I run the car lately. I have not changed the tune at all to do this but I'm wondering how VEAL accounts for EGO input to the actual fuel pulse width. I have EGO control enabled pretty much across the board, so it is always tweaking the pulse width away from where the VE table would put it.

Anyway I am getting an increasingly VE table and wondered if anyone can give me any advice how to best, and most safely, smooth it out? There seem to be quite big regions of the table that I just do not reach when driving - how do I handle this?

I also notice that my idle VE seems pretty low compared to just above idle. Even seen many recommendations not to use VEAL to tune idle VE, so what is the best approach to ensure that the VE table values are appropriate. Should I disable EGO for that region (low RPM and MAP - how do you get very low RPM and mid to high MAP) when the engine is fully warm and just log the wideband AFR readings and see whether the values should be lifted or lowered?

I'm thinking I need to clean this up before moving on to start and warm-up tuning tweaking.

Thanks as always,
Nigel.

[elutionsdesign]

I'd say your table actually looks pretty good, not nearly as lumpy as a lot of them get with just VEAL tuning. There is a built in smoothing feature in the tool bar where you could go in and select small portions of the map to smooth but I don't really think you need much of that.

EGO control is part of the VEAL equation, you'll need to go to the manuals to see exactly how its handled. I always use EGO control and tune with VEAL occasionally so it works fine. There are portions of the table your motor will never operate in, like 500 rpm and 240 KPa boost, impossible. For those impossible cells its nice to go in and blend them into the rest of the table OR just put in the same value so it sticks out where the motor never goes, I prefer the first option as the fueling (and ignition) equations are never using just a single cell for calculating fuel so cells adjacent to those in actual use can be considered for the final result.

Very normal for the cells above idle to be bigger, when you let out the clutch the load goes up but the rpm's don't rise as quickly, most motors like more fuel there. I do disable EGO control in the idle region as a good tune always starts with a rock solid idle which is usually best achieved without extra ECU input. Just pick an AFR the motor likes, most are happier a little rich at idle, like 13.5 or so AFR.

[NigeT]

Thanks for that comprehensive reply. So the ridges and rise, fall, rise patterns I'm seeing are fairly normal?
Normal warm idle is at 850rpm, should I disable EGO much above that?
Thanks again.


Nigel

[elutionsdesign]

I usually set EGO minimum to 1200 or 1300 rpm. Yes, the multiple ridges can be normal, depends on the engine, think of it as an airflow map (which it is).

[NigeT]

Thank you.

How does the air map work - I'd expect it to increase with MAP (higher pressure, more air - simplistic I suppose), just don't see why it would increase and recede with rpm.