[Diy_efi] Re: Newbie ? refined

[Phil Hunter]

Me thinks some of you are missing a very fundamental FI concept.
Duty Cycle is a gross oversimplification, easy to understand
w/o realizing you're missing the bigger picture.

Assume an engine running at 3000 RPM, injectors on continuously
(100% D.C.), AFR is 10:1. Now spin that motor up to 6K RPM,
D.C. is still 100% but what is the AFR? 20:1!!! Why? Same amount
of air per revolution (ignoring VE), but half the time per rev
and therefore half the fuel. Make sure you fully understand that
concept, especially if you bump up the rev limiter, which may
have nothing to do w/ mechanical limits and everything to do w/
avoiding top end lean out.

Let's look at things from a different angle, assume an engine
spinning 6K, 100% D.C., AFR is 12:1. Slow it down to 3K but
keep the AFR at 12:1, D.C. is now 50%, plenty of "headroom" for
nitrous at 3K but none at 6K.

HTHs,
philh
(digest)

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