No, I don't think your missing the point, but are you able to see the air fuel ratio or exhast gas temp or o2 content while you drive, and make sense of it and provide information on what you need to do about the information given to you?
I work as a pilot of a road roughness vehicle. It uses a US data logger which takes road roughness snap shots every 32 feet. Then it converts the roughness readings to an international standard. The thing is, I can drive 17 miles, and get 62000 data points. To get good runs, I have to repeat the process five times to cut out experimental error, and get a good percentile. The data gets dumped into a spreadsheet, and then you decide what you gonna do to the road you surveyed. All I'm interested in doing is making sure the road is the smoothest it can be for each coin my company throws at it, but before I could even do that, I had to set up a whole bunch of spread sheets, and rules, and calibration constants just to get a meaningfull out put. The mantenance crews told me they wanted less info so they could make sense of the reams of graphs I delivered to them. So I had to do a third kind of report so everyone could get there head around it. And I was only looking at one thing...bumps in the road per mile!
With a car, you've got to control all the experimental error and environmental factors. On the road, you just can't do it without many, many runs. In Australia and America, Ford engineers do the final fuel mapping debugging in sweltering weather with the same type of data logger I do, only 100 times more powerfull, and with much more data space. Along with about 20 other thermocuples all over the engine, trans and exhast. They use a Wide Angle O2 sensor which tells you how lean or rich the engine is running. Just the same as CoupeBoy suggests. But what you gonna do with the data, and how do you know the lean fuel air ratio you just caught wasn't a weather change, or cooling problem, and which cylinder was getting steamed, and did the engine knock, and if so which cylinder.
On a dyno, you can create the condition which causes a lean out right away, and do five runs, the minimum required to get a 90% -tile idea of what is happening.
I'm not against getting the technology into the drivers hands, you guys should have a go. It's just that it isn't always a case of backing off on the main jet, or idle screw, or emulsion tube or float level, or ignition advance etc. etc. when you see the sensor go into the red. An O2 sensor will tell you the truth, the whole truth, and nothing but the truth, but only about one aspect...the exhast gas temperature, not a sausage more!
As for me, I've got a Campbells Scientific 8-bit data logger under my bed, and I'm not even about to hook it up to an O2 sensor untill I get someone dynotuning my proposed supercharged 228 engine.
arty:
