Baro Correction Microsquirt

[ajg193]

Hi guys,

Quick question here:

With barometric correction on a microsquirt using a second MAP sensor exposed to atmospheric pressure, what does one need to do with regards to the correction table?

Ie, with the correction table just being 100% for all barometer kPa, does this mean that no correction is applied anywhere or that no correction is applied to some built in correction model within the code?


Assuming that it 100% across the table means no correction at all, do I just adjust the correction at idle for different altitudes to maintain constant idle AFR and assume this correction is appropriate across the entire map? Or is there a more suitable load condition tuning baro correction?

Thanks

[jsmcortina]

Thete's no hidden or built-in correction in current firmware. It is all in the curve. 100% does indeed mean no correction and yes you will need to adjust it to work on your engine.

Ideally adjust during normal driving rather than just idle.

James

[ajg193]

All good, thanks. I took the car up a 400 metre or so hill today and did a little bit of tweaking with the baro table. Looks like about 0.7% less fuel needed to maintain the same idle up there.

I've got a long trip coming up this week (1200 km or so) with a few climbs to above 1000 metres above sea level (normal tune at sea level) so it should be a good opportunity to come up with a reasonable baro table.

Just out of interest, why is the standard barometric correction table just 100%? Do all engines generally require significantly different corrections?

[racingmini_mtl]

Just out of interest, why is the standard barometric correction table just 100%? Do all engines generally require significantly different corrections?

That's a looooong story. If you have a few (many) hours to spend (waste), you can do a search on the forum on the subject of baro correction...

Jean

[ajg193]

I have discovered that Been philosophizing and googling all day about the many possible variables that affect fuel requirements with a change in altitude.

I'm actually amazed that carburetors do such a good job of keeping an engine running in such extremes 'straight out of the box'.

Looks like this should be an interesting problem to tackle.

[Dennis_Zx7r]

I'm actually amazed that carburetors do such a good job of keeping an engine running in such extremes 'straight out of the box'

I doubt that, I think it's more likely because one rarely measures Lambda with carbs. For different altitudes on my bike for example, different jettings are recommended by the manufacturer.

[panel]

I've been doing this also.

If you have a few (many) hours to spend (waste), you can do a search on the forum on the subject of baro correction...

Jean