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Stock map vs modified groupN : why richer ?

Posted: Sun Oct 16, 2011 7:55 am
by Isofouet
Hi,

I recently installed a CAI on my FN2, and I'm beginning the recalibration process.

I want to keep an AFM map because my modifications are quite light.

I started with a groupN base map, and I raised the VTEC point to 5000 rpm (3800 is too low for me)
I modified the VTC tables in consequence.

I'm still in the AFM recalibration step, but I noticed that with this map, i'm running quite rich, and I don't understand why.

For example :

With CAI and stock map :

Image


With CAI and my map :

Image

The AFM XY graph isn't optimal, but it is worse with the stock map.
So why AFR are so rich with this map ? I don't understand because the AFR tables from the groupN map are quite close to the ones from stock equivalent.

Another example is with injector duty : max is 90% with stock, and i'm close to 100% with the modified map...

Should I raise AFR WOT compensation tables ?

I attach my map and a datalog with it.

Thank you !

Re: Stock map vs modified groupN : why richer ?

Posted: Sun Oct 16, 2011 8:18 am
by Isofouet
Another thought :

The AFM recalibration can only be done where there are S-Trim data, ie in closed loop.
The voltage range is within 1-3V

But, in open loop, the voltage can raise to 4V, and there is no recalibration for these values

This plot shows the problem :

Image

After 3V, I didn't recalibrate, as I have no values... Should I extrapolate the values to 4V ?

Re: Stock map vs modified groupN : why richer ?

Posted: Mon Oct 17, 2011 8:09 am
by Hondata
Plot the lambda vs air flow and use that to calibration for open loop.

To get a more accurate plot of making closed loop afm calibration I suggest trying shorter datalogs, where you run under steady throttle so that ths short term trims don't swing as much.

Re: Stock map vs modified groupN : why richer ?

Posted: Thu Oct 20, 2011 9:17 pm
by Isofouet
Thank you, it works wuch better with your advices.

I still need some adjustments, but I've got less S-trims.

For WOT, I aim a 12.6-12.8 AFR, but I run still a bit rich... Is the correct solution to trim the MAF sensor calibration ?

My calibration for high voltage is quite lower from the stock one :

Image

Should I lower it again to reach my AFR goal ?

Plus I don't really understand the point of the WOT compensation table.
AFR should not be raised above 12.5 (or the ECU doesn't go in open loop).
With the groupN calibration, it can't be changed so ?

What does the ECU really do with this table ?

Thank you

Re: Stock map vs modified groupN : why richer ?

Posted: Fri Oct 21, 2011 7:56 am
by Hondata
If you change the intake from stock, then you need to re-calibration the AFM flow vs voltage table based on short term trim. While doing this keep the WOT compensation tables stock (the injectors, manifold, cams and exhaust should also be stock at this point). You can also raise the WOT determination pressure to 90 kPa or so in order to calibration high air flow values.

Re: Stock map vs modified groupN : why richer ?

Posted: Sun Oct 23, 2011 12:03 pm
by Isofouet
Thank you.

If I assume my AFM sensor is well calibrated (good AFMv vs Strim plot), and I have ~12.5 WOT afr (value of the WOT compensation table), what is the setting to have a bit leaner AFR (~12.8) ?

It is not recommended to set AFR in the WOT table above 12.5 (or the ECU doesn't switch open loop)

Is there no solution except a MAP calibration ?