TahoeSS01

here is some interesting statements about wideband o2s-

Quote-
WBO2 sensors measure actually the partial pressure of oxygen in the exhaust. This partial pressure changes for example with altitude. The calibration resistor built into the sensor connector is there so that all WB CONTROLLERS read the same pump current in free air at the MANUFACTURER SPECIFIED AIR PRESSURE. It does nothing else.

The WB sensors used by many meters are OEM parts for production cars. A typical commuter car spends 99% of engine time at idle or part throttle. Full throttle periods are few and far between. A sensor used in a racecar or performance car spends a LOT of time at WOT, with aftermarket turbo tuneups at RICH WOT. Rich operation changes the sensors and makes them age much faster. They go out of (pump current) calibration MUCH before they slow down noticably.
So, using the calibration resistor just means that the sensor is in the ball-park for correct readings. Doing a free air calibration on the other hand is exactly the same as what the sensor manuf. does on a NEW sensor, but corrected for the actual conditions, not the sensor manufacturer's specified standard conditions.

Bosch knows that. Some Bosch ECU's actually DO re-calibrate the WB circuit during coast-down for that very reason. They found BTW that re-calibration IS important in Germany because german cars spend more time at WOT (Autobahn) than US cars. They also compensate for air-pressure differences because the ECU has a atmosph. pressure sensor and CAN therefore compensate

End quote

So as I see it-
How do you want Your sensor calibrated -Free air at install(and on demand) or fixed resistor value at factory ?
And which do you think will be more accurate for all the different elevations we live at?

I have seem a lot of posts on widebands but I thought this info was important as we tend to push the envelope daily.

So the consistant accuracy,not a ballpark estimate of AFR, could mean the difference between good engine life and a melted piston.
We safe guard everything else so this is cheap insurance for any heavily modded truck IMHO.

negativeswitches

iTrader: (15)

i'd liek to know myself :watches:

shimp

So are you saying that we shouldn't buy the AEM WB sensor kit because it is factory resistor calibrated and never recalibrates? We should buy the LC1 kit that everyone keeps saying is crap and goes out all the time?

TahoeSS01

All I am stating is my 3 year experience with my bosch set up on a blown and now n2o truck I have checked the accuracy with many dyno WB..

Here is the Bosch specs for the LSU 4.2 sensor with regards to drifts during aging.
The test was done at a constant 20 deg C with 0.8 Lambda gas and 1.7 Lambda gas.
The drift is 0.02 Lambda (0.3 AFR) after 500 hours and 0.04 Lambda (0.6 AFR) after 2000 hrs in rich gas.
Of course this test was done in a very benign environment.
No rich spikes from accel enrichment, constant temp without heat stress, no soot particles and so on.
It shows why recalibration is needed to get exact results.
Without it you are relying on the sensor calibration when new and have no way to correct the drift.
The factory calibration of the sensor is accurate to +-0.01 Lambda (0.147 AFR)


This is what makes all of us individuals -opinions and the willingness to accept others preferences.

trever1t

iTrader: (14)

Good info. Thanks!

shimp

Okay, so what's a good wideband kit for average tuning that has recalibration as a feature. It was my understanding that you could not recalibrate the AEM wideband, only the LC1 unit.

For those of you who complained about the LC1, is the only problem you had the sensor going bad? Could that sensor be replaced with a better sensor and solve all the problems? Or will you always have to replace the sensor after some time, especially with turbo or supercharged vehicles?

TurboJohn6

iTrader: (12)

I sure as hell would like to know which one to buy. I want to start tuning and need to know. Everytime I think I have it figured out, I see another post that makes me question my choice.

shimp

Yeah I know the feeling.... So which one do we need? It sounds like we need one that we can recalibrate.