we all know what air fuel we want...say like 12:1:1 and so on, but can somebody explain what these numbers mean to me? I have a idea but need to know from some of you more techincally incline or tunners.

here's my guess...the 12:-is 12 parts fuel? ......the :1: is one part air? i don't understand the last :1.....

Thanks.

 

no, its the other way around. Its air to fuel ratio, which means 12 parts air to one part fuel. It takes a lot more air for combustion than fuel. Optimal burning is 14.7 air to 1 fuel, which is called stochiometric. When an engine is under a load you want to try to keep it near 12-13:1 if its NA or sleightly more rich at 11-12.5:1 for forced induction. Leaner is meaner but richer is safer.

 

If you say 12:1 that means 12 parts air to 1 part fuel. You added an extra semicolon, I'm guessing you meant to use a period, like 12.1:1. That means 12 point one (parts air) to 1 (parts fuel).

 

ahh...i was right for the first two..but just got it switch around..but lets say this

12.1:1.....what the last 1 stand for?? crank rotation?

 

smashback has it right.

the number to the left of the colon is how many parts air, the number to the right is how many parts fuel. there are only 2 numbers involved with air/fuel ratios

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by R-1303 &raquo;</TD></TR><TR><TD CLASS="quote">ahh...i was right for the first two..but just got it switch around..but lets say this

12.1:1.....what the last 1 stand for?? crank rotation?</TD></TR></TABLE>

Read the peoples posts! They answer your question.