how do i find out what is a good air fuel ratio ?
for a standered cosworth stage 1 2 ect

and when on say a rolling road wil this move around ?

is there anything i can buy to check that i have good fueling through the rev range whilst driving up my local motor way ?
ie if i have the wrong afr then i can take it to a tuner

i do not wish to map anything my self im not rich

hope some one can help advise me

thanks alan