Moving MAP compensation to main fuel map

Discussion and support for MoTeC's previous generation ECUs.

Moving MAP compensation to main fuel map

Postby Lorcan on Thu Jul 29, 2021 6:09 am

Hopefully this will make sense to someone. We've been using a boost MAP compensation table (Adjust>Fuel>Compensations>MAP Comp) for years in the format 200kpa = 100% increase, 300 = 200%, 400 = 300%, 500 = 400% and so on, as shown in the F1 help for this table. However this table only supports 600kpa as a maximum (5 bar boost) and we have almost reached this point. To run more boost I want to move this compensation to our main fuel map which supports 1000kpa or any amount we choose, and have zeros in the MAP compensation table.

Mathematically, how do I do this? Do I take all the numbers in the 5000rpm column, for example, and multiply them by the corresponding percentage for kpa? Is it that simple?

As a single example we have "55.0" in the fuel table cell for 400 Effcy kpa and 9500rpm. Do I multiply this figure by 3 (300%) to make 165? Is this what the MAP comp table actually does?
Lorcan
 
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Re: Moving MAP compensation to main fuel map

Postby Sean on Fri Jul 30, 2021 4:56 pm

Why not just add more sites in the map comp table with the values you want? I just tried in ecu manager, was able to add sites up to 3000 kpa , I didn't try higher than that. Right click in the table, select axis setup, add / alter sites as required.

Or have I misunderstood the problem? Sean
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Re: Moving MAP compensation to main fuel map

Postby Lorcan on Sat Jul 31, 2021 1:29 am

Sean wrote:Why not just add more sites in the map comp table with the values you want? I just tried in ecu manager, was able to add sites up to 3000 kpa , I didn't try higher than that. Right click in the table, select axis setup, add / alter sites as required.

Or have I misunderstood the problem? Sean


It lets you add to the axis in this way but when you try to fill a cell it won't go past 516%. This is what happens when I try to type "600" in the 700 column.
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Re: Moving MAP compensation to main fuel map

Postby Sean on Sat Jul 31, 2021 10:44 am

Ah, okay, I follow. So, just throwing an idea out there..............

The compensations are all percentages of the base pulse width I believe, so could you use one of the other tables, say fuel comp 1 or 2 as additive to the MAP comp? Example below could get you to 600 kpa possibly....

map comp.jpg
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comp 2.jpg
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If you were not using the EMAP comp table you could change the x axis to manifold pressure and then have half the compensation on the map comp table and half on the emap (as the emap comp has the same range as the map comp), in theory that could get you to 1000 kpa. If EMAP comp is already used but is simple, can that move to comp1 or 2 to free up emap to use in tandem with map comp?

And I should apologise for having a swing at workarounds rather than answering the original question. That being said, if you incorporated the map compensation in the main fuel table up to say, 7 bar, would you not lose resolution in the small throttle / boost areas? Max value of 400 in the table would seem to imply tiny numbers, and therefore big fuel steps at low load.
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Re: Moving MAP compensation to main fuel map

Postby Lorcan on Sun Aug 01, 2021 3:10 am

No apologies needed Sean, I appreciate your input. The emap table thing is too messy for me, although I see where you are coming from. I really need an answer to my original question from Motec support, or anyone else who knows.

FYI it's a compound turbo dragbike. Part throttle resolution is of little importance, it's only ever used in the burnout. It needs to idle between 2000 and 3000rpm, sit on antilag at 8500rpm for a second or two, then operate between 8500 and 11000rpm and 500kpa and 1000kpa for 6 seconds on full throttle. That is all. I don't need super resolution I just need the numbers to go high enough for our application. The main fuel map will do that, I just need confirmation either that the way I propose doing it is correct, or an explanation of how it should be done.
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