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s5fourdoor
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« on: August 04, 2011, 01:57:33 AM »
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Nyet's tuning wiki ( http://s4wiki.com/wiki/Tuning#Desired_AFR) says the following for KRKTE: KRKTE - primary fueling. Start with this to get your WOT AFR to roughly match your requested AFR. If you are using stock injectors and fuel pump, you should not have to touch this. I was just wondering. I've always read that .85 is the optimal O2 voltage for WOT. If my O2 sensor readings are .95, does that mean I have to raise KRKTE? |
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« Last Edit: August 04, 2011, 02:10:03 AM by nehalem »
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NOTORIOUS VR
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« Reply #1 on: August 04, 2011, 05:40:51 AM »
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sounds like you are relying on NBO2 voltages... you should really not be doing that.
that said, 0.95V is richer the 0.85V so no, to go leaner you would make KRKTE smaller.
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s5fourdoor
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« Reply #2 on: August 04, 2011, 09:40:11 AM »
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Thanks. Also thanks for the advice, you are right. Which WBo2 would you recommend? I think I'll buy one today...
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nyet
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« Reply #3 on: August 04, 2011, 09:48:35 AM »
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There are really only two worth mentioning: zeitronix and innovate.
innovate is arguably better, but you need extra junk to log RPM...
zeitronix + boost sensor + rpm pickup works pretty well. Its also nice to be able to log boost past the MAP limit.
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nyet
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« Reply #4 on: August 04, 2011, 09:52:45 AM »
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I never liked this wording. When starting a brand new tune, you should get KRKTE set up so that your part STFTs are near zero (assuming your LTFTs are zero), then later try to get WOT fueling to match req. I'm going to reword the wiki. |
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« Last Edit: August 04, 2011, 09:54:45 AM by nyet »
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NOTORIOUS VR
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« Reply #5 on: August 04, 2011, 10:07:22 AM »
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VEMS also has a really nice gauge... this is their V2:  http://shop.vems.hu/catalog/roundv2wbo2egt-p-166.htmlFeatures: -WBO2 -EGT -various analog inputs (rpm, map and others) -logging -PID boost controller -shift/warning lights all for under $300 USD and if you can deal with slightly less features you can get their V1 (what I am using) gauge which is approx $220 USD |
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nyet
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« Reply #6 on: August 04, 2011, 10:19:47 AM »
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Hey thats not bad  Somebody should get one and send me a log so i can add it to ECUxPlot .. |
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NOTORIOUS VR
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« Reply #7 on: August 04, 2011, 10:26:51 AM »
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Hey thats not bad Somebody should get one and send me a log so i can add it to ECUxPlot .. ok ok... I'll do it... I haven't connected RPM or boost input yet (rpm isn't too hard, for boost I need to get a map sensor)  |
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s5fourdoor
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« Reply #8 on: August 04, 2011, 11:26:54 PM »
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I tried changing KRKTE. My car was running it at .1060.
Using the new ME7 logger @ 20 hz, I figured I'd give it a shot to see if I can draw any conclusions prior to purchasing a wideband.
Using MATLAB, a robust quadratic fit, and my brain (ha!) - I decided to graph
MAF g/s versus the averaged bank1/bank2 oxygen sensor voltages.
There is a DEFINITE structure , which very clearly dissipates and spreads out at lower MAF g/s. At high g/s, I'm willing to wager that the technique I've used here is good.
Obviously a wideband, once installed, will confirm my findings.
Regardless, I thought you guys would geek out over this stuff, so I've uploaded a graph of the "model curves". AKA my progress: KRKTE = .1060, .1000, .0900.
Quick Question: I noticed that my MAF g/s continues to increase as I'm lowering my KRKTE.
When will this G/s delta increase cease? I feel like the point where it stops is close to the theoretically optimal location for KRKTE.
In other words, "you can't flow more air given any other mixture charge". Agree / disagree?
Another Question: I noticed that the car is now stumbling a bit at idle with KRKTE lowered from .1060 to .0900. TVUB is still stock. Do I need to raise TVUB or lower it? Raising TVUB increases the amount of fuel pulsed at idle, right? I'll probably stop my model-driven narrowband tuning until I get a wideband for this alone...
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« Last Edit: August 04, 2011, 11:35:16 PM by nehalem »
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nyet
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« Reply #9 on: August 05, 2011, 10:29:54 AM »
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I noticed that my MAF g/s continues to increase as I'm lowering my KRKTE.
You're probably making more power because your CFs are coming down (less knock) due to richer conditions. |
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