Wide Band O2 Info

[MOTORSPORTS Innovations]

I get a lot of questions on O2's so I put this post to help inform guys on what is going on with O2. (ok, I need money for my junk ) Call me with questions on the O2 stuff or data logging in General. Greg 609-265-2110

Q1 - what is O2 and how does it compare to EGT?

O2 samples the exhaust like EGT but takes lots of samples and uses a heated sensor to get your actual Air-Fuel-ratio in a very short time (like .003 sec) O2 reads all the way down the track (including on the 2-step). So if your car goes way rich for .7 of a second if it comes down a bit hard after a wheel stand, O2 will see that and show you on the graph EGT will not. EGT is best at showing "peak" at the stripe. EGT is cheaper and easier to use.

Q2 - What components are in a O2 "kit"?
There are 3 categories

Gauges - Auto Meter, Innovate, AEM Typical prices $200

Instruments - AFX, FAST, Daytona, Innovate LM-1 & 2 Typical prices $250 - $325 - some of these have a memory to replay the O2 info one the screen or laptop.

Data Logger Input boxes - all the logger companies have their own deal plus you can use AFX, Innovate, Daytona to send info to the logger. $200-$350

Here is the Racepak single channel unit:


Almost all the companies have the controller & sensor - the V-net deal is Racepak. Most use the Bosch sensor that came OEM on bazillion Hondas & VW's. Replacement sensors are about $80 from logger companies. You can buy the sensor for $55 from local auto parts store but some companies use a different plug. Leaded fuels will hurt the sensor. Life varies a lot but 95% of the guys go a full season without needing a new sensor.


Q3. Where do I put the bungs?

The best place is in a primary tube. This is the official recommendation on Racepak and Innovate. The reason is to get the truest sample of exhaust gas - in the collector you frequently get back pulses of clear air.




Q4 - Does the 2 channel unit take 2 channels of the Racepak Sportsman and how long are the wires?

Yes, it does take 2 channels of the Sportsman or V300. The wires are easily long enough to reach primary tubes on each side. almost 48" when you combine the controller extension wires and the sensors. Also, one of the features of the 2 channel unit is that it can be upgraded to 4 channel.



Q5 - what is lambda?Lambda is a fuel independent display method. All the O2's sample at hundreds of times per second and come up with the content of the exhaust. Based on software settings your O2 will display in gasoline Air-Fuel ratios, methanol A-F's, lambda (and other fuels). My analogy is your digital dial caliper - you grab a piece of 1/8" steel - it reads .125 - you push the button for metric and it shows 3.17 - same steel just displayed in a different method.

Q6 - what kind of readings are good?

12.5 - 12.8 usually makes best power before torque peak. After that 12.9 -13.0. There is no perfect reading and yes ignition timing can influence the number.

Give me a call or e-mail with any questions.

Greg

[Tom Goldman]

I learned more about my old carburetor ,none of it good, in 5 or 6 runs with the o2 sensor,than I did in 2 seasons of racing with an EGT meter.
Well worth the investment.

[billy leber]

Originally Posted by Tom Goldman

I learned more about my old carburetor ,none of it good, in 5 or 6 runs with the o2 sensor,than I did in 2 seasons of racing with an EGT meter.
Well worth the investment.

Tom, where did you put your sensors? I was gonna just put one in each collecter. Also ,what brand of stuff did you use, i currently have no data logger and was just going to use the AEM stuff , dont want to spend much on this if possible.

[Alan Roehrich]

I run mine in the collectors. We successfully ran the NGK PowerDex AFX for a couple of seasons, and the sensors held up to everything except the landing from a really out of shape wheelstand. Response was good, and the big LED readout is easy to read.

You know, if you mounted it right, you could use one of those little "Hero" cameras to record video of your runs from inside the car, and it would show the gauges.

I also like the Daytona Sensor stuff. They are really racer friendly, affordable, reliable, and their service is good. If you wanted a really inexpensive simple set up, it's worth a look.

[Tom Goldman]

I started with the sensors in the primary where Racepak recommends them.
After I got the new carb to its best A/F ,I moved them to the collector , about 6" from the merge.
The readings are similar and are ok to just monitor o2 levels,but tuning is better achieved with it in the primary.
With the senser in the collector, the readings while on the throttle stop are meaningless .
There is too much "free air" around the senser at low exhaust velocity,and it always reads the afr as excessivly lean.
The WOT readings are relativly close to those measured in the primary.
Billy , the Racepak Sportsman data recorder was the best bang for the buck I've spent on a part for the racecar.
Way better than my old TAG recorder.

[Rich Biebel]

When I raced an LT-1 Stocker......An Innovate LM-1 from Greg was basically all I used to tune it and I used it all the time during Time runs at every race I went to. I removed the sensor once time runs were over. I had mine in a collector and it was a problem below 5000 getting correct readings. I added some collector extension pieces and the readings were fine after that at lower rpms.....

Ran a best of 10.55 with my home built engine and tuneup.......


I sold the car and the LM-1 with it and I really wish I had kept the LM-1.......

[Ed Wright]

At idle and low RPM, 02 in the collector, it's useless. If you run mufflers there is no problem. On the 2 step it's going to look lean because of misfires. Misfires output oxygen due to incomplete combustion. 02 sensors only measure 02 content, software converts that to A/F ratios. In one primary you could miss a bad injector on that bank, of trash in a jet, until it's too late. In the collector you see an average of all four on that side. To me that is more useful than monitoring one cylinder. Unless you have one in each primary, I don't see that as the best way to go. One dirty injector and the average A/F is going to be lean on that side. Won't tell you which cylinder but will narrow it down.

Dynojet has one, called Wide band Commander that logs data so you can down load it (A/F versus RPM) after a run ot dyno pull. You can also log two other parameters, like for instance, TPS on a foot braked automatic car, and also intake Air Temp, etc.

I like the FAST stand alone wide band (also a version with dual sensors is available), but it would be nice if it logged versus RPM instead of just time. Both of those systems as well as my FAST XFI wide bands in the car and the A/F module on my chassis dyno all show the same A/F ratio on a given pull. You have to learn your tool, some like the one mentioned in the first post won't always agree. You have to find what your engine likes with your sensor. There is no magic number for everything. different fuels even show different A/F ratios in the same car with the same sensors. Like VP C11.

[Bill Edgeworth]

X2 what Ed said.
I think especially on stockers with factory intakes some have particularly bad fuel distribution. I know on my Pontiac stuff the distribution is not too good and to take a reading on any particular tube may be a bit of a gamble. Better to get an average in the collector. However if you do not have collector extensions it can be difficult to get an accurate number. I started out using an LM-1 now I use the dual channel Daytona module tied to a Computech DataMaxx. It’s a great set up for the money. I also think it’s important to remember that different fuels can require markedly different A/F ratios. In my combo over a full point difference between C-11 and C-12. An O2 sensor/Data Recorder can make life easy. If used in conjunction with a program like Crew Chief Pro which can calculate your corrected sea level HP. If you see that your corrected HP is dropping off when your AFR has not changed its can be a good indication you have some engine issues.