Billiumss

iTrader: (11)

I took the car out last night to get some O2 readings. At WOT I am at .940 or higher!!! Sometimes I would hit .960

Then I turned the juice on and figure that it should be lower, well not by much, I was reading around .900-.920

Everyone tells me that the ideal reading at WOT should be .870 mv

I bought some used stock MAF ends so I can take the screen out and so I don't have to ruin mine. I installed them on the car last night. I need to get a few more miles on it before I do more tests and so the computer has time to learn the descreening.

Everything that I read, it should lean my car out a bit.

If it doesn't lean out enough, I guess I can cut out the metal pieces in there to allow a little more air in.

If anyone wants to see my Autotap readings, you can download the files from Here

Just use the playback mode. I was using Ver 1.11.

Bill

Reckless

iTrader: (9)

Think you're gonna be fighting a losing battle Bill. Yes, it will lean out the car. But at part throttle you are driving around lean, the computer learns this, and dumps extra fuel in at WOT to compensate for the lean condition it sees during part throttle driving.

You need a MAFT or tuning to straighten this out.

NoGo

iTrader: (2)

Don't stress it on your O2 readings.

My car is dead nutz 12.8 a/f ratio when my O2's read around .96-.95

Our O2's are NOT accurate at the WOT a/f ratio. Get that thing on a wideband O2 before you start making some major changes to the WOT a/f ratio.

Reckless

iTrader: (9)

I think to be "the most accurate", a wide-band should be utilized. But O2s are usually accurate enough for NA tuning.

Bill...I'll PM you on the COFBA site.
Todd

Spydum

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong>Don't stress it on your O2 readings.

My car is dead nutz 12.8 a/f ratio when my O2's read around .96-.95

Our O2's are NOT accurate at the WOT a/f ratio. Get that thing on a wideband O2 before you start making some major changes to the WOT a/f ratio.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">NoGo hit the nail on the head. Our O2's typically suck, and do not function perfectly. Hit the dyno with the wideband sensor, and go from there.

NoGo

iTrader: (2)

I disagree. O2 readings are highly dependant on exhaust flow and the style of exhaust that you are running.

For example. I just removed my CATs. I made absolutely NO changes to the a/f ratio tuning, and now my O2 readings are around .89 at WOT rather than the usual .95 that I was seeing with CATs. I know that the car is still running around a 12.8 a/f ratio (probably slightly leaner) because it is in open loop control at WOT. However, my O2's are indicating nearly .05 mvolt difference. The O2 sensors are affected too much by differences in exhaust to count them as an "accurate" method of tuning for WOT. They should only be used as a "rule of thumb" type of tuning in which most people should shoot for .85 to .95

Additionally, at .9 mvolt you are 100% out of the mvolt range that the O2's are designed to run about. The O2 sensors are not designed to be accurate or precise at the kind of a/f ratio's that you see at WOT. It is just not an accurate way to tune for WOT a/f ratio.

PewterZ28

iTrader: (1)

My O2s are reading as much as .30 difference from each other at WOT, is this normal?
EX:
B1S1=.930, B2S1=.950 (.20 diff.)
B1S1=.940, BSS1=.965 (.25 diff.)
B1S1=.925, B2S1=.955 (.30 diff.)

Usually they are averaging about .15 difference.

Derrick

Billiumss

iTrader: (11)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Reckless:
<strong>Think you're gonna be fighting a losing battle Bill. Yes, it will lean out the car. But at part throttle you are driving around lean, the computer learns this, and dumps extra fuel in at WOT to compensate for the lean condition it sees during part throttle driving.

You need a MAFT or tuning to straighten this out.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Not what I wanted to hear....

Todd,

Send me a PM or email with your phone number, I want to call you so we can talk....

Bill

PewterZ28

iTrader: (1)

ttt

NoGo

iTrader: (2)

Yes, it is very possible for O2's to very that much.

Back when I thought O2's were accurate at WOT, I used to record my values for different WOT runs. It wasn't uncommon for them to deviate +/- .2 mvolt between various runs.

Good Luck
<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

NoGo

iTrader: (2)

It also depends how your average them. There is alot of Bad or scewed data that gets picked up. The best method I have found is to use a trendline on excel. It makes it much clearer to actually see the average value of the O2's.