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Snow Trooper
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« Reply #15 on: September 16, 2011, 12:42:34 PM »
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some very weird behavior...
now it seems I am discovering what i overlooked before. I am still working with this near stock file to try and lock down blow through tuning. It never requests lambda of less than 1? Why?
If I unplug the maf it behaves like it should in regards to fueling.
In these pulls i didnt lift, regardless of risk of engine failure as I was running e85 for protection against detonation. I was trying to get longer pulls but as the wideband indicated 19.5:1 (lol) it just cut out.
Am i missing something?
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nyet
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« Reply #16 on: September 16, 2011, 12:50:23 PM »
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Are you using BTS? Log calc egt and compare with your TABGBTS
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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Snow Trooper
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« Reply #17 on: September 16, 2011, 01:07:14 PM »
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yes, like I said this is a new behavior thats isolated to the blow through. in draw through it doesnt happen, in speed density (maf unplugged) it doesnt happen.
calc egt is well over tabgbts
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« Last Edit: September 16, 2011, 01:12:32 PM by Snow Trooper »
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Giannis
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« Reply #18 on: September 16, 2011, 01:28:10 PM »
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Mayby the ecu doesn't read enough load so it thinks that you are in low load condition and doesn't enable the high load fuel enrich mode. I think you should try to rescale the maf properly before you proceed any further.
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« Last Edit: September 16, 2011, 01:32:29 PM by Giannis »
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nyet
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« Reply #19 on: September 16, 2011, 01:38:01 PM »
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Agreed. Load is RIDICULOUSLY low. What AFR should you be seeing according to your BTS table?
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« Last Edit: September 16, 2011, 01:42:08 PM by nyet »
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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Snow Trooper
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« Reply #20 on: September 16, 2011, 03:44:04 PM »
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that is actually already scaled, that is a stock 73mm housing scaled up 15% across the board. issue is that anything more and it becomes so rich at idle that you literally cant remove enough fuel.
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Snow Trooper
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« Reply #21 on: September 16, 2011, 03:50:46 PM »
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also, if I scale too much to get the desired maf readings at wot and in boost then the idle becomes the issue as I was talking about in the first post. huge g/s readings and engine load at idle with severe rich conditions to the point of practically needing a negative krkte value...
so far no one has told me what they see at idle in regards to g/s either. do some peoples cars idle with that high of air readings? cause none do that I ever see.
I guess the point of all of this is that i know how to make if work for me at this point on my car. I am trying to understand how and why the maf works this way in blow through. effectively opposite of what every other blow through setup seems to do.
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Snow Trooper
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« Reply #22 on: September 16, 2011, 03:54:56 PM »
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now i am talking to myself... but another thought that i should point out.
my issue with insanely low krkte values is this, maybe you get it in check with the maf plugged in, but as soon as its taken out of the mix (unplugged or fails) the car is running off a crazy low value and is so lean it cant even run. the crazy scaling of the maf is needed to be back in the correct range again in regards to fueling calculations.
remember i base everything off my obsessively calibrated wideband.
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Snow Trooper
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« Reply #23 on: September 16, 2011, 03:57:35 PM »
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Agreed. Load is RIDICULOUSLY low. What AFR should you be seeing according to your BTS table?
i even went back to stock values on like 9.5:1 for bts. my old maps that i had working on the car great with draw through were 11.5-11.6 at full load. this has to be a maf thing, it has to be scale related, i just can figure out how to achieve the right balance without modding other maps, i want to know that air is being properly read. |
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Giannis
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« Reply #24 on: September 16, 2011, 04:11:45 PM »
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Another think to consider is that maf is a sensor designed to suck air from the outer enviroment. If you are using it as blow through the air mesured is far more hotter than the air it should read. So there has to be a map to correct this. Sorry but i cant express correctly in english. For example if you read 4V in suck setup with a stantar enviromental temperature the 4V reading in blow through setup won't be the same because the air temp is now +20 degrees (especially in wot with 1+bar of boost). I think some mafs have an intergraded circuit for calculating the air loss from higher temps. So this circuit affects the maf readings. So this is another reason you can't use just a scaling of 15% across the board. I also wrote before that the scaling for bigger maf is not fixed across the board but varies as the airflow increaces. Sorry everyody for the big topic. I hope that i helped you.
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nyet
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« Reply #25 on: September 16, 2011, 04:13:40 PM »
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i even went back to stock values on like 9.5:1 for bts. my old maps that i had working on the car great with draw through were 11.5-11.6 at full load.
Yea, but what is your BTS at 60% load? Stock is pretty much lambda 1 until 122% |
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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Snow Trooper
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« Reply #26 on: September 16, 2011, 04:19:45 PM »
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hmmm... true... I will have to look. which then brings us back to the maf not accurately indicating load.
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nyet
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« Reply #27 on: September 16, 2011, 04:20:57 PM »
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Which should have showed up in your fuel trims for part/idle, and in wideband vs req AFR WOT deviation.
Also, modern MAFs should be properly temp corrected, even with +20F variations.
If in doubt, check the sensor datasheet.
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« Last Edit: September 16, 2011, 04:22:51 PM by nyet »
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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Giannis
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« Reply #28 on: September 16, 2011, 04:31:57 PM »
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I meant +20C not Fareneit. Mayby there is some limit until witch temp can be corrected. In a wot run with no correct afr and ignition as in this case, it can reach 100+C max IAT. I think that a sensor designed for reading air from the enviroment won't correct in such temperatures.
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nyet
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« Reply #29 on: September 16, 2011, 04:45:51 PM »
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Excellent point. On my K04 car, I rarely see over 150F IATs (65C ish), but I can certainly see it is possible for a blowthrough setup to get air temps that are beyond the spec of MAFs intended for ambient.
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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