Can we have more baro correction bins?

[msoultan]

Hey Guys,
I was wondering if it's possible to add more baro correction bins. I was just doing some testing and what I was doing was setting a new data point at every 1000ft. I'm not sure if the curve is supposed to be linear or not - the baro tuning windows says non-linear. So for that reason, I wanted to put a data point at every 1000 ft up to at least 9,000 ft. I'm thinking that we bump it up to 10 bins, first starting at sea level.

I noticed the following value in ms2_extra.h that defines the dimensions of the barocorr values array:

Code: Select all

#define NO_BARS 	6

Can this just be bumped up to 10 and then change this line in the INI file:

Code: Select all

      baroCorrVals    = array ,  S16,    864,    [    6], "kPa",      0.10000,   0.00000,  0.00,  400.00,      1 ; * ( 24 bytes)

with 10 for the array dimensions?

Thanks!
Mike

[muythaibxr]

It's not that simple, but you're in luck... I think there's enough room to do this on that page:

Code: Select all

EAEAWW[12], /* added to the walls CLT scalar */
	EAESOW[12], /* pulled from the walls CLT scalar */
	placeholder[20];
    int
	BaroVals[NO_BARS],   // Barometric pressures (kPa x 10) for baro correction table
	MatVals[NO_MATS];    // air temperatures (degx10) for air density correction table
    char
	BaroCorDel[NO_BARS],   // Barometric corrections (+/-%) - added to eq. value
	// to correct for varying exhaust size
	AirCorDel[NO_MATS];    // Air density corrections (+/-%) - added to eq. value

So there are 20 bytes free just above where you need them... you're asking for 12 more bytes of tuning data... I'd have to rearrange the data in that immediate area, but I don't think it'd be too difficult.

I'll see what I can do this weekend.

Ken

[msoultan]

Sounds good. I've been using percent baro in addition to baro correction and it's working really well so far. Let me know when it's ready and I'll test it out. I'll be going up to the mountains in a couple weeks.

Thanks!
Mike

[Philip Lochner]

Sounds good. I've been using percent baro in addition to baro correction

Baro correction is very important for me too. Mike, are you saying that you use both the two point baro correction as well as the 6 point table?

I have adopted the approach of setting the two point table to 100% all over and rely only on the 6 point table for my corrections. It helps to see a trend.

I'ld like to understand why you need more than 6 points though?

[msoultan]

Hey Philip,
What two point barometric correction are you using? I don't think that exists anymore.. at least I didn't think so.

What I use is Percent Baro and the 6-point barometric correction. Are you using percent baro? It's money..

Mike

[Philip Lochner]

The B&G fw had "two point" baro correction table. They added the 6 point later in addition to the 2 point table for finer corrections.

It wont take much for me to become confused between B&G fw (that runs on my Landy) and Extra fw that runs on the Jag.

You've just brought my attention to the fact that I have no clue what "percent baro" is and will have to read up on that. I sense that this is something unique to Extra?

[Philip Lochner]

Found the "2-point baro table" (in the extra fw...) as in MT Extra !!

Go to tools, sensor calibration, last two lines:

I have "at total vac" set to 100 and "rate" to 0. This way only the 6 point table influences the baro correction.[/img]

[muythaibxr]

You've just brought my attention to the fact that I have no clue what "percent baro" is and will have to read up on that. I sense that this is something unique to Extra?

B&G have it too, but I think they call it something different... MAP/BARO maybe?

Ken

[hassmaschine]

The B&G fw had "two point" baro correction table. They added the 6 point later in addition to the 2 point table for finer corrections.

It wont take much for me to become confused between B&G fw (that runs on my Landy) and Extra fw that runs on the Jag.

You've just brought my attention to the fact that I have no clue what "percent baro" is and will have to read up on that. I sense that this is something unique to Extra?

I could be wrong, but this is how I understand it: % baro compensates for the max pressure reading you will get at high altitude - say you were at 5000ft and local pressure was 80kpa. without % baro, the highest load site on your VE table that you could reach at WOT would be 80kpa. %baro fixes this so it will hit full load (100% for an N/A engine) on your VE map.

[msoultan]

The B&G fw had "two point" baro correction table. They added the 6 point later in addition to the 2 point table for finer corrections.

It wont take much for me to become confused between B&G fw (that runs on my Landy) and Extra fw that runs on the Jag.

I'm doing everything w/ ms2extra. I have not played with anything in the tools/sensor calibration settings.

KEN, do I need to set those values to anything? Right now I have it all at 0. I'd like to just use the 6-point adjustments for now...

You've just brought my attention to the fact that I have no clue what "percent baro" is and will have to read up on that. I sense that this is something unique to Extra?

Percent baro is awesome. It accounts for changes in map values as you go up in altitude so it doesn't affect your VE, AFR, and any other tables that rely on MAP. This way, your tables are no longer altitude specific.

here's where it all started:

http://www.msefi.com/viewtopic.php?t=24421&highlight=

[muythaibxr]

I think I had the idea independently but at the same time as Al... probably implemented it around the same time too.

I don't actually know about the behavior of the 2-point stuff... I've never used it! I'll have to take a look and see what I can find there.

Ken

[msoultan]

I don't actually know about the behavior of the 2-point stuff... I've never used it! I'll have to take a look and see what I can find there.

Ken

Hey Ken,
If you could look into the 2-point behavior, we might not need more points on the 6-point table. I was doing some more tuning today at altitude and it's actually looking pretty linear. I was thinking it might be logarithmic or exponential or something, but it's not shaping up that way.

Thanks,
Mike

[Philip Lochner]

% baro compensates for the max pressure reading you will get at high altitude - say you were at 5000ft and local pressure was 80kpa. without % baro, the highest load site on your VE table that you could reach at WOT would be 80kpa. %baro fixes this so it will hit full load (100% for an N/A engine) on your VE map.

Yes, this is what B&G call map/baro and determines the load based on MAP divided by Baro. I prefer to use absolute MAP as load determination (particularly on the ignition timing side of things - I then have baro timing retard built in) With map/baro (or %baro) 50% load will be 50kpa at sea level and will be 25kpa where baro is 50kpa (just to make the figures stress the point).

But this has very little to do with barometric correction which is tuned with the 2 point table under Tools (IMHO also not needed) and the 6 point table (where I do all my baro corrections so I can see the trend).

[muythaibxr]

OK well, I'll leave that table alone for this release then.

[msoultan]

But this has very little to do with barometric correction which is tuned with the 2 point table under Tools (IMHO also not needed) and the 6 point table (where I do all my baro corrections so I can see the trend).

I'm curious why you don't think it's needed. The first area map/baro (% baro) makes a big difference is with the AFR table. If you don't use it and go up to altitude, the AFR selection is all wrong. This also holds true with the VE table and I would assume ignition (don't use ignition control). Plus, if I don't use some kinda baro correction, my mixture is very rich at 6k versus sea level.

[Philip Lochner]

First, let me just ensure that its understood that I'm not saying that %baro(or map/baro in B&G fw) is not needed. On that topic I am saying that I just prefer not to use it . (If you really want to understand why, perhaps another thread?)

I am saying that I think the 2 point baro correction table is not needed and that the 6 point table can do it all. Keep in mind that my understanding of the relationship between the 2 point table and the 6 point table is based on my understanding of the two tables relate in the B&G fw and I'm assuming its the same in the Extra fw.

The 2 point table offers a linear baro correction for all values of baro. The slope (rate ) and Y-axis crossing point ("at total vacuum") can be set by the two values one enters. However, as nature would have it few things in life is linear, so the 6 point table was added such that the 2 point curve can be fine tuned. The value of the curve in the 6 point table is merely added (or subtracted) from the value of baro obtained from the 2 point table.

So, if I set the 2 point table values as follows:
"at total vacuum" : 100%
"rate": 0%

then I end up with a horizontal line giving 100% correction for all values of baro.

Now, if I enter either + or - values in my 6 point table, these values are added to the 100% only 2-point table and thus represent the total correction implemented. Eg: the 2-point table will have 100% at all points, so if the 6 point table yields 5% at a given baro pressure, the total correction is 105%. I find this works perfectly as I can easily move between 1000m and 1800m within about 100km and I'm a bit particular about having the same AFRs at the same point on my VE table - which I now have (with my MS 2 Extra beta 18 fw).

Hope I've managed to explain myself.