Quote:
Originally Posted by serialk11r
I think forced induction gas engines have low AFR because they use the excess fuel to cool down the charge. Maximum power comes at something like 13:1 or so where the excess fuel can consume all of the air, but after that the excess fuel is wasted and you get less power since you're cooling the charge more. But it's a necessary evil when you have very high boost.
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Yeah, you're shooting for 12.5:1. That's the magic number that gives you the most power, but under boost, you have to enrich the AFR. Many pistons have been melted with too lean of a AFR under boost.
The nice thing is, with a predictable spool up, you can usually get away with leaning out the AFR in the cruising range.