Changing RPM points on Tables. Calculating new cell values.

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Changing RPM points on Tables. Calculating new cell values.

Postby Nigep » Wed Jan 18, 2012 1:15 am

I am running MS1 V3 in Alpha-N on my car.

The system is working fine, the map is as good as I can get it and i`m happy with it.

However, there are a couple of RPM points on the MAP that aren`t where I want them to be. As the MS1 has limited resolution, I want to move the RPM points on both the fuelling and spark tables.

Is there an excel sheet or similar that someone has created that lets me put in my current table, then on a `target` table, I can change the RPM points and it calculates the necessary fuelling values using the same calculation as Megasquirt.

I have a couple of small AFR dips that can be seen to change as the fuelling goes into the next cell, I`m wanting to try and tune this out, but need to increase resolution in those areas at the expense of more stable zones.

Obviously, I could do it by trial and error, but if there is a method of automating the calculating of the desired target values, that would obviously be my first choice.

Nige.
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Re: Changing RPM points on Tables. Calculating new cell valu

Postby Nigep » Mon Jan 30, 2012 12:48 pm

Image
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Re: Changing RPM points on Tables. Calculating new cell valu

Postby E4ODnut » Mon Jan 30, 2012 5:37 pm

I don't think there is an easy way to this and it will probably mean a re-tune in those areas. I stand to be corrected though.
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Re: Changing RPM points on Tables. Calculating new cell valu

Postby ol boy » Mon Jan 30, 2012 7:08 pm

I'll give it a shot.

Your looking for the proportion between the 3 cells, 1 to the left and 1 to the right of the cell column you want to move. ie.. your rpm columns are 700, 900 and 1300, but you want 700, 1000 and 1300. Take your VE numbers at 60% load/TPS ie.. 50, 57, and 70. With 700 to 1300 rpm a 600 rpm spread, 1000 rpm would be half way between 700 and 1300, while 900 was not. Your spread from 50 to 70VE is a difference of 20, so half of the spread added gets 10 added to the lower number of 50 to get a new VE number at 60% and 1000 rpm, 60. Do this for each value you want to change.

The Delta change to the percent difference in columns. In the example above 57 is 1/3 of the way to 70 as 900 is of 700 to 1300.

Hope this helps, Later Ryan
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Re: Changing RPM points on Tables. Calculating new cell valu

Postby Nigep » Mon Jan 30, 2012 7:23 pm

I need to read that a few times to get my head around it :RTFM:


Thanks for the info.
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Re: Changing RPM points on Tables. Calculating new cell valu

Postby ol boy » Mon Jan 30, 2012 9:22 pm

tell you what, export your VE table, zip it and post with what you want to move around.

Try this first.. In TS open the VE table in the tuning tab all the way to the right. You can see how smooth or not so smooth the VE table looks. As long as you have 'even spacing' unchecked you can see where your rpm columns are unevenly spaced. If you change a rpm column without changing the VE numbers you will end up with a mountain or valley for that column being shifted to the right or left. Increase or decrease the VE numbers until you get the smoothness back between the cells around the column you changed.
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Re: Changing RPM points on Tables. Calculating new cell valu

Postby Nigep » Sun Feb 19, 2012 8:26 am

I`ve put together the following spreadsheet, it takes the original values and uses them to calculate the `new` values depending on the desired RPM and/or MAP/TPS values.

I haven`t added any error checking. If you have a smaller or larger value in the destination table, it will give an error.

This should help change RPM points if your original values are no longer where you need them, I found I have a gap in my table and I needed to change the rpm points, hence this spreadsheet.

Hope someone else finds it useful too. The source values I used are sample values, not a working map.

Any suggestions / bug reports, please reply in this thread and I`ll sort it (if I can).

Macros will need enabling to allow the interpolation calculation to run

Nige.

Screenshots showing the VE and Spark table pages
Image
Last edited by Nigep on Sun Feb 19, 2012 1:54 pm, edited 4 times in total.
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Re: Changing RPM points on Tables. Calculating new cell valu

Postby jsmcortina » Sun Feb 19, 2012 8:45 am

I presume you are doing it as an example, but just to point out that you can't use the Y axis "upside down" like that in Megasquirt.

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Re: Changing RPM points on Tables. Calculating new cell valu

Postby Nigep » Sun Feb 19, 2012 9:13 am

Spreadsheet tweaked to show output table in correct orientation. :)

Download link in post above.
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Re: Changing RPM points on Tables. Calculating new cell valu

Postby smudge » Mon Apr 09, 2012 2:38 pm

A very useful spread sheet thanks Nige :D I altered my idle rpm and tsp ranges the other on my ITB car, because of new throttle position, worked very well and saved me having to calculate each change manually. Cheers Tom.
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