HI guys what would you say is the ideal afr at idle on a large half bridge 13b

Cheers Paul

 

mine idles in the mid 13s to low 14s at 1400rpm

 

Do you still have your icv? Mine idles low to high 13s idles at around 1500rpm

 

The ideal ratio is wherever the engine is most happy by having the most stable idle, drawing the most vacuum, and the cleanest exhaust.

An idle control valve is not going to be useful for a bridgeport except to raise the idle (open loop) during warmup.