Dealing with Phantom knock?

[s1ngletracker]

ah yeah, good call. I just don't know how to convert voltage to A/F... any idea?

[Halon]

Run the tank down real low, and go put a couple gallons of C16 in it, and see if the knock goes away.

[s1ngletracker]

Where can I get C16?

[Shane@DBPerformance]

ah yeah, good call. I just don't know how to convert voltage to A/F... any idea?

You can't convert volts to A/F without a wideband gauge. .5v on a narrowband is 14.7:1, it is only accurate right around .5v. The stock ECU and stock narrowband O2 only care if it's richer or leaner than .5v/14.7, not by how much.

The dummy gauges don't read in A/F either. They just have huge ranges covering rich, stoich, and lean.

But any ways, your O2 volts should be like .92-.98 under boost, unless you have a 1990. And even with a perfectly flat wideband A/F of like 11.0:1, your O2 volts will change, instead of holding a consistant .96v or whatever. You could have a perfect A/F and your volts might go from .90 to 1.00 across the RPMs. So they are almost useless for tuning outside of idle/cruise.

[s1ngletracker]

How does the O2 look on this log?

LINK (http://www.mediafire.com/?0weydqtnhmk)

[s1ngletracker]

I realize the stock narrowband O2 is inaccurate, I just want to know if i'm rich or lean... not exactly how much.

Let me phrase it this way. Do you know what voltage represents stoich on the stock O2?

[Halon]

Stoich is 14.7. So if he said .5V = 14.7, then he is saying .5V = stoich.

[Shane@DBPerformance]

Don't log so many useless things and edit your logs to just pulls. I only saw 1 row in that whole thing that was 100% throttle.

Does it knock at cruise or full throttle or part throttle with some boost?

.5v is stoich on a stock O2.

[s1ngletracker]

the problem is most prominent at part throttle with boost.

Yeah, sorry about the messy log. I just realized that there wasn't much full throttle. If 0.5v is stoich, i'm at least not running TERRIBLY lean. I'm hitting about 0.90v

[Kevin 1G Drummer]

I believe Shane said 11.0 AFR is roughly .9 volts at WOT, so you shouldn't be lean at all. From the way I understand it, >.5v = rich and <.5v = lean.