[Kalns]

Hello.

Lately I have noticed a lot of talk about these options and whether they should be enabled or not..

So I am wondering if I should enable any of the given options under VE table and if they are any good or not, assuming I am using latest firmware to date. And If there are some additional options that need to be configured if using these? Like AFR protection operation ranges or something else ?

Multiply VE value by MAP ratio
Multiply VE by ratio of AFR to Target AFR
Multiply by ratio of stoich AFR/target AFR (incorporate AFR)

Bare in mind that I am not fully understanding what these options are doing from two sentences under help icon or wiki..
At the moment I have not enabled them, since once I tried and wbo2 failed, got so rich fueling that engine could not rev past 4.9k rpm ... so I disabled them and retuned VE table to avoid this happening again..

[jonbill]

The one to definitely NOT use the 2nd, AFR to target AFR.
The other two have no dependency on the real time o2 sensor response and are safe.
You can read about them in the wiki.
https://wiki.speeduino.com/en/configuration/VE_table

[pazi88]

Yeah, the wiki has pretty good info about those options and what is recommended.

[Kalns]

I have read this wiki section like 5 times and still do not understand what is meant by it. Like I can set my settingss as suggested, but do not understand why it have to be like that. I like to question things

So a resume would be like this ?
Multiply VE value by MAP ratio - Set to Fixed ( because of wiki and because I do not use barometric sensor )
Multiply VE by ratio of AFR to Target AFR - Set to NO
Multiply by ratio of stoich AFR/target AFR (incorporate AFR) - Set to YES

And by doing this I assume it will flatten my VE table, as wiki says and will use wbo2 for corrections to get lambda = lambda target, am I correct?

Also about Lambda..
Any recomended settings for AFR correction Algorithm?
I am thinking that it shold be used up to (including) cruse speeds ~3500rpm and only if lambda is inbetween 0.8 and 1.2, so if lambda sensor dies it does not affect the tune. Am I on the right track or should this be something compleatly diffrent ?

[jonbill]

I think the usual advice is to set the first to MAP:Baro, which gives correction for atmospheric pressure. Although you don't have a Baro sensor, speeduino takes a Baro reading before engine start and uses that.

Multiply by ratio of stoich to target doesn't involve your o2 sensor at all. Just the stoichiometric ratio defined in your tune and the target AFR table. It allows you to simply adjust the AFR table and the fuelling will adjust automatically to the new target. (But it'll be no more accurate than it was before - its just maths)
When you have a good/accurate tune and a wbo2 sensor, you can use the pid algorithm. I think the usual advice is to set it to operate between a narrow afr range and only limited authority and lowish load.
I think mine is set for 12.5 to 16 afr, 7% authority and only upto 10% TPS.
But I'm sure others have other preferences.

[Kalns]

I have noticed that if baro correction is disabled, it still reads some value and it jumps around 95 to 105 kpa, and if there in table is set something diffrent than 100 for fuel, then it might upset the tune alot, so I have zeroed (100) the table to avoid this "feature" Only when I noticed that it reads something other than 100kpa I did this and it fixed most of the problems where barrometric correction would have affect even if its disabled as a sensor input.

Thanks everyone for input, it cleared up a bit what and why is going on.

[PSIG]

Also about Lambda..
Any recomended settings for AFR correction Algorithm?
I am thinking that it shold be used up to (including) cruse speeds ~3500rpm and only if lambda is inbetween 0.8 and 1.2, so if lambda sensor dies it does not affect the tune. Am I on the right track or should this be something compleatly diffrent ?

When you have a good/accurate tune and a wbo2 sensor, you can use the pid algorithm. I think the usual advice is to set it to operate between a narrow afr range and only limited authority …

^^This. There are no "rules", but seems a good place to begin. As most know, I let the system read and log O2, but I do not use any O2 corrections at first, as I do not want the box to alter the engine's response to a tune change. If I lean it a bit here, I want to see that change in running, not let the box 'fix' it for me to the table Lambda value. We do not know the best AFRs for this engine and fuel yet, so I don't let it try to correct to the 'incorrect' values in the AFR table. Yet.

Once the base tune is firming-up and the good Lambda values are known and entered in the AFR table, I first limit corrections to only a range that will run the engine without partial or full misfires, then continue with tuning. BTW - these are similar filters I use in TS and MLV log filters, as I do not want them to alter fueling if (example) the engine is in rich misfire, reads lean O2 because of it, and adds more fuel when it's already too rich.

A concept I use is that a set of parameters are discovered in tuning and operation, outlining the "normal" range of Lambda the engine sees. I then limit the corrections to only apply, slowly, to that 'normal' expected range. The better the tune, fuel quality, etc, the narrower the range. This covers normal operation, mostly covers some anomalies, but prevents uncontrolled corrections or wide swings in fueling due to various reasons from bad data, dead sensors, etc.

[Kalns]

Yes, definitely, o2 corrections should be enabled only when VE table is set in place and only minor changes are needed..
I was mostly curious about settings that are in VE table, as a bit wider explanation would be nice to have, or help file / links in general about all the features.

Anyway, now I understand a bit more about this, thanks for input.

[pazi88]

I think the usual advice is to set the first to MAP:Baro, which gives correction for atmospheric pressure. Although you don't have a Baro sensor, speeduino takes a Baro reading before engine start and uses that.

Yes that was previously when there was no fixed option available nor baro correction. But now there is actual baro correction with curve to adjust, so the baro-option is not really needed. Also the baro option is bit risky to use without separate baro sensor, because in that case Speeduino takes map reading as baro when it boots up. Which is generally fine. But if ie. your connection to pc cuts out while engine is running and it reboots speeduino. It can take what ever is the current vacuum value as baro reading and throw off the tune untill next re-start. So it's recommended to use the fixed option and separate baro correction.

[jonbill]

I think the usual advice is to set the first to MAP:Baro, which gives correction for atmospheric pressure. Although you don't have a Baro sensor, speeduino takes a Baro reading before engine start and uses that.

Yes that was previously when there was no fixed option available nor baro correction. But now there is actual baro correction with curve to adjust, so the baro-option is not really needed. Also the baro option is bit risky to use without separate baro sensor, because in that case Speeduino takes map reading as baro when it boots up. Which is generally fine. But if ie. your connection to pc cuts out while engine is running and it reboots speeduino. It can take what ever is the current vacuum value as baro reading and throw off the tune untill next re-start. So it's recommended to use the fixed option and separate baro correction.

Thanks Pazi. I remembered it the other way round, but I've been back and reviewed some threads on Discord and of course, you're right.