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ig. timing advance VS. O2 Voltage (1G/GVR4 ONLY!!)

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Mitsuturbo

20+ Year Contributor
87
5
Feb 5, 2003
Seattle, Washington
FIrst off.. this was done on 17psi, 91 Octane, and 34deg IATs. (yes, utah is THAT cold right now)
Ran some quick logs on the car last night, and i "know" my o2 sensor is pretty well shot, changing it tonight most likely, but my question is this.. do the o2 voltages affect how much timing advance you're getting? I assume they do, since it's the ECUs ONLY way of knowing how rich/lean things are running. Since my o2 is peaking at like .76v, i am speculating that this is why i am only seeing like 14-15 deg. timing advance. Correct?

this was with ZERO knock as well.. in case you were wondering
I lowered boost to 9# and got 22deg of advance, (saw the same o2v) so i'm left wondering if the ECU isnt comparing Hz to o2v and basing timing from there

I know the 2g is stingy with timing and basically "pulls" timing on the higher airflow maps. I have been told by a great many people that the 1g/GVR4 is not like this.

Thanks.

91 GVR4, 8.8:1 compression, Ported head, evo3 big16, 3" turboback, 550's, 2g maf, SAFC, SITC, DSBC-R, Apexi EGT
 
From what I learned, O2V on our cars don't relate when tuning for knock/timing. I run 16psi and have 0-3 counts and timing ending at 19°-20°. My O2V's are everywhere, ending anywhere from .81 to as low as .76. You maybe be getting only 15° with 0 counts of knock because of too little timing. What is your Karmen on a 3rd gear pull? What is your base timing set at? This all plays a factor on how much timing you will get on a WOT run.

my_gst95
 
The computer only uses the O2 signal during closed-loop operation at idle and cruise (low load conditions), and it doesn't use it for timing, only fuel.

At WOT, timing is based on maps within the ECU, and then changed if you have knock, high coolant temps, hi intake temps....
 
Originally posted by my_gst95
From what I learned, O2V on our cars don't relate when tuning for knock/timing. I run 16psi and have 0-3 counts and timing ending at 19°-20°. My O2V's are everywhere, ending anywhere from .81 to as low as .76. You maybe be getting only 15° with 0 counts of knock because of too little timing. What is your Karmen on a 3rd gear pull? What is your base timing set at? This all plays a factor on how much timing you will get on a WOT run.

my_gst95
Hz at the top of 3rd @ 17psi, with a 2g maf, ends up around 1850hz
Coolant temp is staying right at 200deg or below

My base timing is set at 5 deg, but the ITC can adjust that anywhere i like. I have tried different ITC adjustments throughout the range, and nothing seems to yield more automatic ignition advance for me.

I guess i'm somewhat confused, since the ECU's only way to tell how rich or lean you are, is with the O2 sensor voltage. So i assumed that the ECU would loosely base timing on that, among other factors, such as IAT, ECT, and HZ.
 
Keep in mind that if you add timing with the ITC, it's not going to show up on the logger since the logger doesn't know it's being changed.

Timing is based on airflow per rev, and engine speed. Then, it is modified depending on knock.
 
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