MAF Scaling - Open/Closed Loop Fueling info

[solidONE]

Originally Posted by thambu19

@solidONE
I think I get it now. So there are two ways of making sure the AFR is right. 1. Adjust the MAF with a bump at 3.0V ish or 2. Increase load limit at around 3K rpm.

This is done because if not done the engine will run lean at 3K ish rpm. What about the other engine speeds then? Why would it not run lean at those? Is it because at the other engine speeds the load limit isnt clipping yet? Meaning to say that at 3K rpm the intake performs better than at other rpm?

Would you have a copy of @Wayno xml?

Yes, that or LTFT's will be higher after computer had done some learning. But, then the rest of the rage will likely become too rich due to the increase LTFT. Not sure whether if this means the intake performs better at 3K vs stock, because if you rescaled the MAF for accuracy using completely stock components without adjusting the load limits, that lump will probably still be there.

@Wayno has the files linked at the bottom of the first post in his thread labled "WW 2015-09-17 OFT Defs.zip": http://www.ft86club.com/forums/showthread.php?t=94822


This is just considering the MAF scales and load limits. Once you get further into it you will also find that the MAF intake temp compensation will make the car run richer in cooler weather and leaner in hot weather. I've just about come to the conclusion that it cannot be perfected. My approach is to have it dialed in so afr's don't become richer than 12.0:1 in cold weather and no leaner than 12.5:1 in hot weather in OL operation and call it a day.

[steve99]

Originally Posted by thambu19

I agree. If the MAF is causing the engine to use a 15% positive fueling correction the engine will run as if it will bog down because it will be looking up a spark 15% higher which is usually more retarded. Worst would be at WOT where in OL the engine will receive 15% excess fueling for no good reason. I just did not understand that bump in the middle of the curve and I think @solidONE had a neat explanation as to why it is needed.

I dont get that big bump but maybe its just differences in intake or maf sensors.

I have stock Intake maf scale and fairly linear rising load limits

looks like this on E85
http://datazap.me/u/steve99/uel-v5-e...zoom=1226-1532


maf scale
[Table2D]
0.90 0.9
0.94 1.1
0.98 1.2
1.02 1.5
1.05 1.7
1.09 1.9
1.13 2.2
1.17 2.5
1.21 2.7
1.25 3.0
1.29 3.3
1.33 3.6
1.37 3.9
1.41 4.4
1.45 4.6
1.48 5.1
1.52 5.6
1.56 6.2
1.60 7.1
1.64 7.8
1.68 8.3
1.72 9.0
1.76 9.8
1.80 10.5
1.84 11.2
1.88 12.0
1.91 13.0
1.95 14.2
1.99 15.1
2.03 16.0
2.07 16.9
2.11 18.0
2.15 19.1
2.19 20.5
2.23 21.5
2.27 22.8
2.30 24.0
2.34 24.8
2.38 26.4
2.42 27.6
2.46 29.4
2.50 31.3
2.58 33.6
2.77 42.6
2.97 52.2
3.20 69.5
3.44 87.0
3.71 110.8
3.91 131.5
4.06 147.2
4.30 179.1
4.49 208.4
4.73 247.8
5.00 307.1


load limits
[Table2D]
800 0.9
1000 0.9
1200 0.9
2000 1.0
2200 1.0
2400 1.1
2600 1.2
3800 1.3
4000 1.4

[thambu19]

I read his post and man it was quite a bit to handle even for someone who does calibration as a profession

[thambu19]

@steve99 Are you using the Takeda intake as well? I just ordered mine. I hope the intake sounds good

[steve99]

Originally Posted by thambu19

@steve99 Are you using the Takeda intake as well? I just ordered mine. I hope the intake sounds good

nope :-) just completley stock intake even the filter

I helpd a couple of guys with takeda/gready (same thing) they are a but of fun as they seem to introduce turbulance at lower rpms, although I think their has been a design change so it may be better now.

[solidONE]

^ @steve99's MAF and load limits tables look the tidiest. Maybe you can try a similar calibration and see if that get's you where you want to be. But, first I would scale the MAF table so that when displayed in a graph it looks nice and smooth (not too many lumps or bumps) with LTFT's below 2~3% after learning in CL and AFR's past the 3.0v mark in OL as close to target as possible. Then, I would start making changes to the load limits. After that's done, you can go back to make minor tweaks to the maf scale again to try to get it even more accurate.

[solidONE]

Originally Posted by thambu19

I read his post and man it was quite a bit to handle even for someone who does calibration as a profession

LMAO!

[JB86'd]

Why does the MAF intake temperature compensation make the car run richer in cold weather, and leaner in hot weather? I'm no expert but I would think that is backwards of what it should do.

When looking at the table, it looks like the MAF value has a positive % increase as temperature goes up, wouldn't that richen it?

[solidONE]

Originally Posted by JB86'd

Why does the MAF intake temperature compensation make the car run richer in cold weather, and leaner in hot weather? I'm no expert but I would think that is backwards of what it should do.

When looking at the table, it looks like the MAF value has a positive % increase as temperature goes up, wouldn't that richen it?

What I mean is the unmodified calibration causes it to run richer in cooler temps. I've tried messing with the intake temp compensations and got good results in CL operation from +110 down to sub 50 temps, but not in OL where it's more important, as the STFT will adjust for any lean-ness or richness in CL operation anyways.

Go take a WOT log in 100 ambient temps, then one in 50 ambient temps. Compare the 2 logs and you will know exactly what I'm talking about.

[JB86'd]

Originally Posted by solidONE

What I mean is the unmodified calibration causes it to run richer in cooler temps. I've tried messing with the intake temp compensations and got good results in CL operation from +110 down to -50 temps, but not in OL where it's more important, as the STFT will adjust for any lean-ness or richness in CL operation anyways.

Go take a WOT log in 100 ambient temps, then one in 50 ambient temps. Compare the 2 logs and you will know exactly what I'm talking about.

I believe you. My point is more, why would they set the temp compensation to do that? And also, the table looks opposite to me, maybe I'm interpreting it wrong.

[Kodename47]

Originally Posted by JB86'd

I believe you. My point is more, why would they set the temp compensation to do that? And also, the table looks opposite to me, maybe I'm interpreting it wrong.

I'd be suggesting that it's setup with air density in mind, warm air is less dense and therefore the same amount of fuel will make it run rich and the opposite for lean conditions. So to counter that you remove fuel for high IAT and add fuel for lower IATs. I think that the standard compensation is just a little to aggressive in doing so.

[freerunner]

Originally Posted by Kodename47

I'd be suggesting that it's setup with air density in mind, warm air is less dense and therefore the same amount of fuel will make it run rich and the opposite for lean conditions. So to counter that you remove fuel for high IAT and add fuel for lower IATs. I think that the standard compensation is just a little to aggressive in doing so.

Exactly that.

We used modified intake air sensors signals for tuning motorcycles back in the days, when it was uncommon to reverse engineer ecus.

[solidONE]

Originally Posted by JB86'd

I believe you. My point is more, why would they set the temp compensation to do that? And also, the table looks opposite to me, maybe I'm interpreting it wrong.

That's one of those things you'd have to ask the engineers at Fuji Heavy in charge of the engine management, along with why their calibrations has so much damn knock.

[thambu19]

I am guessing: In order to keep calibration efforts minimal they calibrated to the best 93 octane fuel available and decided the knock control system can adapt to the rest of the fuels? Looks like they have the same spark, cam cal etc for cars in Australia, Europe, USA and everywhere else. I think they are one of the few OEMs that I have seen utilizing a spark addition algorithm. Most OEMs dont add spark they just take away spark due to knock.