Accuracy of this method of calculating AFR

[2gGSX]

From DSMLink I've logged a pull, then made a table for InjDuty, Airflow, AFR and Calculated AFR. I derived calculated AFR through getting fuel flow in lbs/min by: InjDuty x 660 x 4 x .76 / 454 then dividing airflow (lbs/min) by this number. My question is how accurate would this calculated A/F ratio be? Obviously I should just get a wideband and test it out but, well I'm a little poor now

 

[spyderturbo007]

You do know that DSMLink will "estimate" the AFR for you.

I know that you aren't supposed to reply with an "I heard" statement, but this is from a person that knows way too much about DSM tuning.

I have hear from Kevin Jewer (aka 95GSXRacer), that in his experience of comparing DSMLink's AFR calculation to a WBO2, that the calculation is very accurate.