About AFR Target map

[Roger-Dee]

Hi all

I'm reading more and more on megasquirt, and I want to know how much easier is it to tune it using the afr tables and a wideband?

[740ATL]

Well... you don't necessarily need the afr target tables to tune.

From my understanding, the afr targets are just the afr ranges that represent the ideal for a general load-vs-rpm range. In a way, whether you are manually tuning, or regular-old-datalogging/tuning, you're still always using the AFR targets... in your head... you're still tuning based on a pre-set image of what the table should look like in terms of AFR vs load/rpm.... the difference really is in how much input you have into that process.

that's my initial thoughts.... Personally, I haven't used the afr targets for tuning yet... I've only done the manual tuning and datalog style tuning so far.

Mike

[blkaplan]

I use my AFR tables to power my 02 correction. You can tune with them as well, eventually you should just use them so you can get day to day correction

[JohnMc]

It uses the AFR targets if you have autotune (and a laptop) turned on. I've not always been too happy with the results of autotune, but recently I put on a new exhaust system and moved the wideband up to the downpipe from the previous mounting in the front of the cat. So it might be a bit more responsive now.

Autotune is a feature of megatune, not megasquirt, so it's only going to happen when you have the motor running and a laptop plugged in. But the AFR targets are also used in calculating the EGO corrections if you are running in closed loop mode. Which, if you have a wideband, there's not much reason not to. (Actually, autotune uses the EGO correction amounts too, it just looks at them and then tweaks the table accordingly).

Autotune does well at fine tuning areas of the curve where you spend a lot of time, like cruising. But it's hard to spend a LOT of time in full boost acceleration, because it is usually ripping up through the rpm bins so fast it doesn't really have time to tune any of the cells. The log analyzer in Megalog Viewer does a little better, because it can look at multiple acceleration runs, average them all together, and tweak the table. But you are still probably a little better off tweaking those areas of the table by hand.