Converting Lambda to A/F ratio and getting confused

[HPLouis]

I'm doing some datalogging on my car and I'm reading my A/F ratio in Lambda. I want to convert it but I'm wondering which value to use.

I see .756 in Lambda on my wideband. If I use gas stoich (14.64), I get 11.06. If I use E10's ratio (14.079), I get 10.64.

I'm just trying to figure out if my A/F ratio is 11.06 or if it's 10.64? All that I've read said to get to .789 Lambda and that's 11.5 but that's the gasoline stoich. If I use the E10 stoich, it's 11.1

Thanks

 

[SVTXTC]

I'm doing some datalogging on my car and I'm reading my A/F ratio in Lambda. I want to convert it but I'm wondering which value to use.

I see .756 in Lambda on my wideband. If I use gas stoich (14.64), I get 11.06. If I use E10's ratio (14.079), I get 10.64.

I'm just trying to figure out if my A/F ratio is 11.06 or if it's 10.64? All that I've read said to get to .789 Lambda and that's 11.5 but that's the gasoline stoich. If I use the E10 stoich, it's 11.1

Thanks

AFR

14.64 to 15.2 accept
16's 17s cautious

Below 12
11's mid elevens good spot AFR

10s overly rich

9s and 8s bad rich


Just forget AFR all together. Lambda is always lambda. No conversion needed. .74 is fine if you’re in boost. Just a hair fat. 1.0 or higher is good for driving around part throttle.

In boost you should be in the .7 range no leaner than .78. .78 is ideal target for WOT

Never be alarmed at part throttle as long as car runs well. It could be as lean as 1.5 on deceleration and that’s fine. There’s are specific dfco tables for this to abound backfiring etc. Part throttle .9 to 1.0 is all good.


When you get into boost it should richen up almost instantaneously and anywhere from .72 to .78 is plenty safe. Avoid backfiring/ gurgling. Not abound. WOT at .80 or higher is a problem. Anything in .60s is way too fat.

Hope this helps

 

[HPLouis]

Just forget AFR all together. Lambda is always lambda. No conversion needed. .74 is fine if you’re in boost. Just a hair fat. 1.0 or higher is good for driving around part throttle.

In boost you should be in the .7 range no leaner than .78. .78 is ideal target for WOT

Never be alarmed at part throttle as long as car runs well. It could be as lean as 1.5 on deceleration and that’s fine. There’s are specific dfco tables for this to abound backfiring etc. Part throttle .9 to 1.0 is all good.


When you get into boost it should richen up almost instantaneously and anywhere from .72 to .78 is plenty safe. Avoid backfiring/ gurgling. Not abound. WOT at .80 or higher is a problem. Anything in .60s is way too fat.

Hope this helps

Perfect. Thank you

 

[2003RedfireVert]

Doesn’t this depend on what Lamba is in your tune?