Imback
15+ Year Contributor
- 1,300
- 263
- Nov 8, 2006
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Long island,
New_York
The jump in your cells between 6000 and 6500 is to drasitic. That's causing your airflow to start looking jittery around that rpm and above.
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Its much smoother now, both boost stability and AF.Did something improve that I'm not seeing? It's still choppy af.
Switching to a 5bar sensor cut your resolution significantly.
The GM sensor seems to have an issue, and the VE map has bias tuned into it.The jump in your cells between 6000 and 6500 is to drasitic. That's causing your airflow to start looking jittery around that rpm and above.
This is a 50PSI sensor, not the 75PSI sensorIt's smoother because half the resolution is missing.
I agree! Which post is missing a log you were looking for? - I went back a week and attached the pictured logs.Post the pics if you want but you should also post the actual log file. Makes it easier for us to see everything.
Here is a log of a car I was working on a few years ago, this is a pull before the clutch gave up. This is comparable to you as it's a 16g @ 17psi, very similar physical setup. I left boostest on for keks. But seriously, look at how stable it is.Choppy? Ok. I'll take 1psi oscillation over 4psi oscillation, even if it turns out that the sensor is smoother due to improved filtering. The air turbulance caused by valves opening and closing is not helpful to capture in the data used to deliver fuel.
The voltage resolution you are referring to is: 0.03v less per psi - ~27% difference.
GM3Bar - 9.1 psi/volt or 0.11volt/psi
ZT-35bar - 12.5 psi/volt or 0.08volt/psi
In comparison
ZT-5bar - 18.75 psi/volt or 0.05volt/psi ~45% difference
Both resolution and sensor filtering will help to smooth out the data - and in this case, I say that is a good thing.
The blue Omni4Bar line on the screen is super hard to see - and that sensor looks like it is producing smooth output.Here is a log of a car I was working on a few years ago, this is a pull before the clutch gave up. This is comparable to you as it's a 16g @ 17psi, very similar physical setup. I left boostest on for keks. But seriously, look at how stable it is.
It may be interesting to swap the brake booster and the MAP sources on the manifold.ECMTuning User Support Forums
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I have not - but I like the suggestion. No need now with a better sensor.Have you tried mechanically smoothing out the response with a snubber? I've used them in hydraulic ram systems that are PID controlled as well as leak detection systems that have to read 0-2 inWC ( 0.072 psi) with 100psi dynamic operating pressure. You'll probably have to play with the orifice size but they make more expensive ones with changeable "pills" similar to a nitrous jet.
MHI e16g, ebay o2 housing, unknown 3" downpipe ending under the driver's ass. Intercooler, BOV I hate, standard MBC ball/spring. It's a fairly stock car.But - as you show, 17psi is smooth. Now, do you think it is smooth because the pressure in the manifold is smooth or do you think the PSI is smooth due to the way the sensor is designed?
Boost control on this pull is very good - What kind of setup was the turbine, o2, WG and downpipe.
Yes - closed loop is working, Fuel trims are +- 5% and during idle, the minimum InjDuty cycle is 1.2% with these RC-1000cc injectorsI've been away from tuning for awhile and I have limited experience using ECMLink, but I am curious, do you have closed loop fuel trimming enabled? If so, what's the minimum injector pulsewidth correction per cycle?
YupI'm assuming you're using much larger than stock 450s.
It probably won't - that is a good data point to check.Might try locking into open loop to see if it still oscillates.
That is a BISS adjustment, as 101 as it sounds.I'm getting closer to MAX boost again. I saw 27.3 PSI in the initial boost spike and then 24psi tapering down to 22psi - but I don't have enough WOT data yet. A few more runs and I'll have the map filled out.
What I'm wondering is if anyone has SD Idle hunting like we see in the beginning of the log. This starts happening after everything is nice an warm/hot.
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I don't know Jus, mine does the same thing sometimes, I think. I have a hard time seeing it in my logs. But when I'm in the car and judging rpm by sound, when I hear an oscillating idle speed and look at the wideband gauge, it usually seems like the higher or stronger idle sound corresponds to slightly richer on the wideband gauge, which would be a voltage hump (high) on the front O2.The period of the idle hunting matches the signal from the front 02 sensor cycling:
Hmm, I'll try NB simulator and see if that changes the result. I wonder if a new front 02 would resolve this.