When it's stock and unmolested, the numbers are perfect.

If they read wrong it's either because your WB reads wrong at the rich end of the scale OR the fuel pressure is wrong or usually BOTH.

 

You've really got a hard on for Fuel Pressure being the reason for all issues...

 

The AFR on the fuel map, that comes from the engine development engineers using an engine dyno which measures mass flows of both air and fuel.
What's displayed converts directly the actual IPW required to make that AFR given the correct fuel pressure.

If you change the fuel pressure, the AFR is automatically wrong.
If you tune it wrong to try to get around the wrong fuel pressure, you also get it wrong.
When the WB reads wrong..........it's wrong.


If it's tuned right......the numbers will be the same.

 

nope, not even on a fully stock car...

 

If you turned off Lean Spool it would probably be closer.

 

I highly doubt that is one of the dumbest statements ever, but thanks for the credit.