Factor/Offset for WBo2 input

Superdave · Post by **Superdave** » Wed Jun 13, 2012 3:02 am

I noticed the other day that while going down the track my WMS wideband was showing mid 11 AFR's and my datalogs are showing mid 12's.

Using a '7730, $A1 mask, BFUZ code with Ryan Hess's hack from many years ago and his matching .ads.

He's got the factor at .0392, Offset 10.

Operation is Multiply ([X*Factor]+Offset).

It's fairly close at idle between the controller and the Tunerpro display.

Any help is appreciated.

Thanks

Post by **robertisaar** » Wed Jun 13, 2012 8:32 am

i don't know what controller Ryan used to come up with that equation, but it's probably different than what your controller is pushing out.

Superdave · Post by **Superdave** » Wed Jun 13, 2012 7:23 pm

Found this for the AEM UEGO: "(2*voltage)+10 so the conversion factor in TunerPro would be (2*x/50)+10."

That makes everything show leaner.

I'll contact Western Motorsports and see what they say it should be...

rts91tsi · Post by **rts91tsi** » Thu Jun 14, 2012 3:20 am

The AEM white papers, which may or may not be correct from what I've read, list the full scale voltage of the sensor to be 4.99v, basically 5v. The papers also list the AFR scale from 10-19.98 for gasoline, basically an AFR range of 10.

Additionally, the ECU will interpret the voltage it sees as 0-255 from an 8 bit ADC. These numbers will need to be plugged in to form the equation to convert the ECU's interpretation of the WB signal, to a useable AFR reading on the logger.

It would look something like this: AFR= x*(10/255)+10

AFR range of 10, divided by 255 (based off 8 bit ADC, how the ECU will report max voltage)= 0.0392 rounded off.

.0392 * 128( how the ECU would report 2.5v)=5.0176

5.0176 + 10=15.0176 AFR=2.5v, which from the white papers, is almost spot on.

Again this will all depend on the exact voltage output from the UEGO. The UEGO is also sort of picky about how it is grounded(shorter wire length is usually better), which can lead to a variance in the external AFR reading.

Additionally you can conduct the test shown from the video to dial the equation in for your setup.

http://www.youtube.com/watch?feature=pl ... mb4VmDd0ao

Six_Shooter · Post by **Six_Shooter** » Thu Jun 14, 2012 2:41 pm

It looks like the conversion is very similar to the Innovate LC-1.

In my ADX, the conversion is: X * 0.100000 + 0.000000

But this may be more affected by what's in the bin, since there are a few selections for different WBO2 sensors, both linear and non-linear. The non-linear selections have their own look up tables.

Post by **robertisaar** » Thu Jun 14, 2012 2:45 pm

A1, not code59.

Six_Shooter · Post by **Six_Shooter** » Thu Jun 14, 2012 6:29 pm

I realize that, but this is a Wideband issue, which may or may not have the same conversion, mearly putting out what I know works in other cases.

Superdave · Post by **Superdave** » Fri Jun 15, 2012 3:26 am

WMS replied, it's a linear scale.

I may just start using it's built in logger if i can still get the cable from them.