Stock A/F ratio

[laza101]

Hi all,
Anyone know what the factory DSM air/fuel ratio is set at for wide open throttle? I'm sure someone has put a wideband sensor on one. Thanks!

 

[Kevin Jewer]

Not sure about 1g, but 2g is set to 9.5:1 if you are on the max airflow map, over 2.1 grams/rev airflow. What you get at the WB depends on any intake leaks, accuracy of the air metering system, and accuracy of the fuel delivery system (injector flow, dead time, and rail pressure).

Suffice it to say the factory shoots for a pretty rich mixture, for 2g at least.

 

[laza101]

The reason I'm asking is because I'm currently running stock ratio. Is there room to lean it out on 650cc's with 50 trim @ 20psi?

 

[kpt4321]

1g's get down to 9.3:1 at higher engine speeds on stock airflow.

I can't tell you if you have room to lean it out, you need to datalog the car to find out.

How do you know you are running stock A/F ratio?