Valuable information about narrowband oxygen sensors...

[10_SS]

nice I didnt know you could cut logs... huge help. Thanks

Regarding the logging rate... for example I log my RV GM 8.1 workhorse on 1-3hr trips, Im not sure I will be able to do that with 3.0 due to the large file size... any way I can slow that logging rate down? It would be a nice feature for long trips.

[Keith@HPTuners]

If you want less data, don't use broadcast parameters.

[gmtech16450yz]

nice I didnt know you could cut logs... huge help. Thanks

There are a TON of little features like that in 3.0. I'm telling you, use 3.0 for a solid month or so and then go back to 2.24 and see how much you're missing as far as speed and features. Things like auto saving logs, that one is HUGE!!! How many of you did a nice long log with tons of data and forgot to save the log? 3.0 auto saves every log when you stop logging. F ing awesome little feature. Saving and sharing config or Layout files is also WAAAYY better. Pinch the screen for zoom in and out on a touch screen, I use that one all the time now.

Here's another HUGE one, "View Zoom Data Range Only" in the graph or histograms. Holy cr@p that's useful!!! You have a half hour drive with city and freeway driving but only want to work on the freeway steady cruise mixtures? Zoom in on only that part of the log and the histograms will only populate with that data. And it moves along when you move the zoom or section of the logging window! That's powerful stuff guys.

For me the proof is in the results. I've had onboard logging in my daily driven LSA Sky for a few years now. I literally have a couple thousand logs since I log everytime I drive the car. I'm a driveability guy, that's my specialty. WOT tuning is easy and pretty brainless, it takes a few runs to get that stuff dialed in and you're done. What I work on damn near everyday is pursuing the ultimate fuel control and driveability. What it's given me is how to tune a 700+whp car to where it starts just as fast on a cold morning on full e85 as on gas, as well as perfect throttle response, mixture, ignition timing and idle control. Here's what I've seen since switching two things, a fast AEM 30-0300 wideband and inputting it into v3.0 through the CAN network instead of using 2.24. The result is I've gotten the closest fuel control I've had in literally hundreds of logs and tunes.

I've made a big deal about narrowbands in this thread because I don't think guys realize how important having not only an ACCURATE feedback of exhaust content, but TIMELY feedback. I truly believe that a large percentage of modified cars are being tuned with either slow or inaccurate widebands. Have any of you ever gotten to the tuning point of feeling like you're chasing a moving target on fuel control tuning? If you're changing values in fuel control cells that aren't EXACTLY where the fuel issue is, you'll never get commanded and actual to line up. THAT'S what I've seen as being different since using 3.0 and this new wideband. Histogram data is far more accurate because those values are hitting in the proper cells, not the one's right after or before.

Anyway, Thanks again for jumping in Keith. I'm glad we got the "false data" idea put to bed. I've compared Channel data to Chart data also. I personally use the Chart Display 90% of the time when tuning. The Channels values are just numbers. The Chart Display is what's showing you "trends" or directions of change over time. THAT'S the important stuff. Interpolation is a good thing. It's the whole basis of compression and expansion in damn near every aspect of computer or digital file use. Anyone that's used Photoshop HAS to understand Interpolation. Yes, there are times when it is a bad thing obviously. You can't take a 15megapixel image and compress it down to 3Mb and expect to not lose valuable data. But when there's a huge portion of that image that's the same values, you also don't need 50thousand pieces of data with the same values saved in a file. As far as HPTuners Chart Display and Interpolation goes, I have NO problem with it interpolating between my 10ms data points of important parameters. I'm thrilled just to get data at every 10ms!!! Verson 2.24 gave me that same exact data every 48ms or so.

[dr.mike]

I knew 30ms was too long for the 30-0300s

[Mr. Smith]

Epic (10 month old) thread (so I don't feel bad for resurrecting it).

Can someone please tell me why my narrowband readings are all over the place?
In the Graph layout and in the "O2 (mv)" table, I'll get mv readings like 777, 750, 616, 215, 59, 750, 806, 103, 850, 508, 70, 491, 905... for example. Is that normal (for 10 minute drives/logs?) and how can I get the mv's spot on in all the cells?
My VE/fuel trims are not bad.. and the better they get, they don't seem to affect/improve my 02 mv's.
Car runs great, engine feels strong, everything else is okay...
Also, I get different 02 readings in "Channels" compared to "Graph". They don't seem to be an average of the two sensors.
I have "02 Voltage B1S1 SAE" and "02 Voltage B2S1 SAE" selected in my Channels list.


Team narrowbands and STFTs FTW

[schpenxel]

That isn't how it works. Just use fuel trims.

[Mr. Smith]

Thanks Schpenx.
So are your 02 narrowband mv's like mine too?

[schpenxel]

How many hits do you have in the oddball cells?

I haven't been logging O2 voltages lately but from a few random old logs I have pretty similar numbers. Probably just hit that cell when it was on the lean end of the "swing" or whatever. It only takes something like +/- 2% to make NB O2 sensors swing from lean to rich

[metroplex]

Thanks 10_SS! You saved me a bunch of typing! And no, that absolutely wasn't a stupid question jtrosky, it was actually an excellent question.

As 10_SS stated, narrowbands do a very good job of keeping the mixture at stoich by switching back and forth between too rich and too lean. There is another big reason that most manufacturers have stayed with narrowbands, and that's the catalyst operation. A 3-way cat NEEDS the mixture to be both too rich AND too lean, that's how it operates. The very short explanation is that if what's going into the converter was perfect combustion, it wouldn't have the elements needed to control NOx. So since the cat needs the mixtures to swing back and forth between too rich and too lean, a switching oxygen sensor works great for that.

And yes, some cars already have widebands from the factory. The Bosch E69 used in the GM Ecotecs like the LNF have factory widebands. Not only that, they run in closed loop at all times, even during WOT. If LS engines had closed loop WOT fuel control there would probably be half of the blown engines that there are now. When you do a mod that makes a constant closed loop engine too lean, it doesn't blow up because even at WOT it knows it's lean and richens the mixture automatically. (In general terms obviously.) The fuel control in a Direct Injected Bosch E69 LNF is amazingly accurate. It makes tuning an LS engine seem caveman crude in comparison. LTFT's are normally within -5 to +5%, even from the factory. I usually shut off LTFT's because STFT's are plenty enough control in those engines, and even those can be tuned to stay within a -10 to +10% span. Watching commanded and actual Lambda in the logs, they're almost always exactly the same. Oh and they use Lambda in those ECM's too, none of this AFR or EQ Ratio stuff. lol.

Every Ford EcoBoost also comes with widebands and runs in closed loop all the time. The Ford "PE" table is called the Closed Loop WOT Lambda table, IIRC.

I have been toying with the idea on using narrow bands for wot tuning on my 07 Mustang, by disabling open loop, setting desired lambda to 1.00, and reducing the timing so I can monitor fuel trims out to 6500 RPM. My theory is that the trims will tell me how much I am deviating from stoich with the transfer function. Once the function is dialed in, I could then enable open loop mode and restore timing. I figure the ecu can now command 0.85 based on a transfer function that was tuned for stoich.

I looked at some of the transfer functions developed by vendors and it seemed like the changes made to the closed loop portion matched the higher voltage sections in terms of percentage delta over a stock MAF. In other words, the scaling or correction factors didn't deviate a whole lot at WOT vs. Normal closed loop.

[guitarZ]

Higuys,

I'm putting together an Arduino circuit to display AFR, so does anyone have a detailed chart or table for a narrow-band oxygen sensor?

[schpenxel]

A narrowband can accurately tell you two things

1. You’re richer than lambda = 1
2. You’re leaner than lambda = 1

There is no telling an exact AFR with them

[guitarZ]

The old-school guys have been using it for many years with success.

You can make a decent calibration chart, and software can get you further to a good mixture adjustment, but you can't get extreme precision with it.

[dr.mike]

As you move away from the midpoint, at lambda 1.000, the voltage curve is HIGHLY dependent on EGT and exhaust back pressure. You can't map a voltage to an AFR/Lambda value with any useful repeatability. Better to get the arduino to read a WB output. Either voltage, serial, or CAN.

[mbray01]

creating any type of chart referencing o2 mv to afr, or lambda, would be nothing more than a rough estimation at best. In this thread there was a post giving one of those rough estimations. That was that individuals findings in reference to his experience with narrowbands vs widebands. I have a chart I use specifically, that is different than theirs, that coincides with my findings. There are way to many factors that play into this. narrow bands are in no way shape or form accurate beyond lmbda 1.0. Having said that when I tune a fuel map, and have it dialed in. I generally want to see a narrow band reading around 900mv +/- 10mv on na applications. lighter cars I want on the - side, trucks or heavier vehicles on the + side. If I have readings outside of these numbers, I generally find that there were errors somewhere else. These numbers are for basically stock applications. anything else would require wideband use. also pay attention to both narrowbands reading the same in 2 bank systems. if one is reading 910mv and the other 830mv, well either you have a mechanical issue, or one is lying to you. You will never find a 100% accurate chart because none can exist. Different manufacturers will have different slopes, heat plays a huge factor in that slope, and the age of the sensor is also a huge factor as well.