What are GOOD A/F Ratios ??

[jondee86]

Just fired up my LC-1 Wide Band Controller and A/F gauge. Took the
car for a short run to see what sort of numbers I was getting...
12.5 @ WOT
14's and 15's @ just driving around
13.3 @ idle (you can see the off throttle idle enrichment working )

Just curious to know if these are good numbers ??

I'm running a simulated narrow band output to the stock ECU. Will go
to direct wide band data out to the aftermarket ECU when it gets installed.

Cheers... jondee86

[IH8TEC]

seems pretty good to me, i'm assuming this is NA? cause turbo i'd want a bit richer on WOT and boost.

[Lith]

Yeah they sound pretty ideal for an NA setup

[jondee86]

Sweet The instructions have a bunch of stuff saying that your readings
can be off if you have bad earths. So I wanted to check that I was in the
ballpark with the actual readings.

Yeah... NA for sure, and the stock smallport ECU doing a good job taking
care of a little bit of extra air from mild cams and poddy intake

Cheers... jondee86

[strx7]

12.5:1 seems a bit rich for an n/a but in saying that all motors are different, and some prefer to be a bit richer while other prefer to be a bit leaner, somewhere between 12.7:1 and 14.0:1 is what most n/a should be at WOT

[jondee86]

Just found this on another forum tonight...

This is from "How to Tune and Modify Engine Management Systems"
by Jeff Hartman

Air/fuel Mixture and Characteristics
AFR Comments
6:0 Rich burn limit (fully warm engine)
9:0 Black smoke/low power
11.5 Approximate rich best torque at wide-open-throttle
12.2 Safe best power at wide-open-throttle
13.3 Approximate lean best torque
14.6 Stoichiometric AFR(chemically ideal)
15.5 Lean Cruise
16.5 Usual best economy
18.0 Carbureted lean burn limit
22+ EEC/EFI Lean Burn Limit.

As said, seems to indicate there is a bit of latitude on the AFR's
according to what you are tuning for. Factory tune will be on the
conservative side to cater for shopping basket use.

Cheers... jondee86