Wide band O2 sensor vs HCCO meter

I was talking to a VW tuner, who uses a wide band O2 sensor, instead of a HC/CO meter. He states that he knows of no one, who tunes VWs, that uses an HC/CO meter.

He feels that the air/fuel ratio measurement is accurate, and that an HC/CO meter is not necessary.

These guys have pulsed injection systems, with programmable ECUs that can be adjusted for any RPM, thus they are able to set the fuel where they want at any RPM......thus the use of the wide band sensor for measurement.

My K and KE-Jetronic Ferraris are only set at idle speed. Would a wide band sensor be of any benefit, over the HC/CO meter?

I don't seem to read anything about people using this on a Ferrari, in the posts.

Actually I debated someone in the past about the usefulness and accuracy of the two.

The bottom line was the Exhaust Gas Analyzers (CO/HC Testers) give FAR More info about what's going on in the engine.

While the Wide Band O2 sensors have their usefulness, they are very limited in what they can do or tell a tuner.

Maybe once the VW gys move up to the Big Boys Toys they'll want to additionaly add to their overall knowledge base as well.

JRV: Can you give an example of where a wide band sensor would be useful, over an HC/CO meter?

When I see graphs, in texts, of A/F ratios, next to those of HC/CO ratios, it would seem that they correlate at the lambda=1 position. Thus, getting the A/F ratio at 14.7 (Lambda=1), at idle, would correspond to the "best" HC/CO reading. What am I missing?

Thanks

Henry,

what you're missing is that with WBO2 there is no CO or HC only O2...so you really don't know what's going on in the engine...and unless everything with the engine is in perfect condition you're not really 'tuning' with the WBO2, simply compensating.

For example...with your GA you saw readings on your Boxer of .50% CO % 300ppmHC with that "data" we were able to not only tell you a likely reason for the poor numbers 'lean miss', but also what to do to correct the situation...with a WBO2 if you had a bad plug /plug wire for example, there would be no 'data' to give clues as to the solution...and even in your case of a lean miss the WBO2 would give no data to hint at a cure, because the WBO2 is simply an adjustment device not a diagnostic device.

Each tool has it's place....and on a programmable EFI system one would have to have a WBO2 in place to adjust A/F Ratio across the entire spectrum of use, but adjusting without additional data is risky to the engine itself and not a be all end all. To 'really' tune & tweek engines takes a very large variety of data to not only set A/F ratio but also to maximize HP & dial in safety margins for longivety.

Here's a good example of the WBO2's failings...355's...

They have a computer and 2 O2 sensors per bank to read & change A/F Ratio 'in real time'...however when something happens..bad/dirty injector for example, all the system can do is turn a MIL on. It can't diagnois or fix the problem...then one must check the exhaust with a GA to determine the true nature of the problem, and what to do about it.

So the bottom line is the WBO2 is still years & years away from being able to match what a GA can do..and more likely the GA's will become small enough to be mounted in a car for true OBD's and the WBO2 will be an apendage to the GA. In fact if you think about it GA's already have an O2 sensor plumbed in as the 4th gas.

Most interesting dialog...

I've always viewed an exhaust gas analyzer as a diagnostic tool...and any sort of O2 or WB02 device as a merely "where am I" with respect to the A/F ratio.

This company has very interesting white papers pertaining to the significance and meaning of 4/5 gas readings...

http://www.bridgeanalyzers.com/Docum...Paper%2010.pdf

JRV and Hank...Thank you for sharing your questions, answers and perspectives. I love to expand my knowledge base!

Regards,
David