Since I have datalogged that the computer gives you a little more timing advance when leaning out the air/fuel ratio, I was wondering if I should try and lean the car out more.

What would be a "safe" O2 voltage to run at WOT? Currently I am tuned to run at 0.87-0.88V at WOT in 3rd gear (that O2 voltage is technically the approxomate air/fuel ratio where a regular internal combustion engine on "normal" gas should make the most power).

There should be a point where the power gained from some extra timing advance is negated by running the wrong air/fuel ratio, or I will start knocking and the timing will pull anyway (or I start to risk engine damage). I wonder if more power can be safely gained from leaning out some more.

Any opinions/advice/experience with this?

"Tutto fa brodo."

Todd Scungio
98 RS
15.173 @ 90.70 MPH

And also a 2011 Ralliart

your ecu advances the timing when the mixture leans out? that's weird.. seems kinda backasswards to me

I've head like .78 is about where you would start to notice detonation... I wouldn't push it down that far though. If you really want to find out get some wideband O2 dyno tuning done. I think eventually I'll do this, I went with Greg for Hujjat's Dyno, now I just want to see mine up there. And compair your data logs to the dyno runs and see what the good voltage is for 12.5:1 air/fuel ratio.

Una salus victus.
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yea, I could use some dyno time, and once I get a few more mods on, then I'll really need to get the car tuned properly

So far I am aiming for about 12.5 or 12.7 to 1, which "should" be about 0.87V on a normal O2 sensor, but as we know that can vary as each O2 sensor is a bit different, and a normal automotove O2 sensor isn't that accurate at that air/fuel ratio

tomorrow I might try a bit leaner while monitoring O2 voltage, but I doubt I'll go down much more than another -2% at 7000 rpms

"Tutto fa brodo."

Todd Scungio
98 RS
15.173 @ 90.70 MPH

And also a 2011 Ralliart

so, does leaning out increase compression?

'98 Eclipse GS - The slow screamer.

Mods? If God wanted us to mod cars, he would make aftermarket companies. Oh wait... yeah i better get to work on that.

No...leaning out is less fuel per amount of air.

99GS MT | Star Stage 2 | GC coilovers | HurriganeGS tie bars | Tokico Illuminas | 17x7 Enkei RS5 | Baer track brakes |+

yes, i knew that much i was just wondering what he meant when he said he was aiming for 12.5 to 12.7 to 1.

'98 Eclipse GS - The slow screamer.

Mods? If God wanted us to mod cars, he would make aftermarket companies. Oh wait... yeah i better get to work on that.

heh heh, wasn't clear there

12.5 to 1, air to fuel ratio

"Tutto fa brodo."

Todd Scungio
98 RS
15.173 @ 90.70 MPH

And also a 2011 Ralliart