Lean with no knock??
01-18-2007, 01:25 PM
#2
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Absolutely. People do it to achieve better MPG. Lean just means that the A/F is greater than the stoichiometric value ~14.7:1 for gasoline. I am talking about part throttle or idle conditions if you're so inclined. It is not a good idea to run lean at WOT. You'd be surprised how lean an engine can actually run under light load conditions.
01-18-2007, 01:39 PM
#3
Honda ULEV motors run up to 20:1 A/F. But thats at cruise, low load.
I see posts on here all the time about how so and so's car is too lean at 13:1. 13:1 IS NOT lean. It is leanER than 12:1, but it is still RICH. As in below stoich.
PS dont be hatin bout the Honda comment.....
I see posts on here all the time about how so and so's car is too lean at 13:1. 13:1 IS NOT lean. It is leanER than 12:1, but it is still RICH. As in below stoich.
PS dont be hatin bout the Honda comment.....
01-18-2007, 01:57 PM
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With spark timing pulled back to what the motor wants you
can run pretty lean. I do not know if these motors will go
diesel at high cylinder pressures and stoich, or not. If you
do not diesel then theoretically you can run as lean as you
like (though the EPA has another opinion on that).
Flame speed vs mixture falls off at both lean and rich
extremes (there is also an upper and lower explosive limit
for all combustible mixtures). So you might be able to run
insanely lean and still not detonate, although this is not
going to be good for power or economy as the charge is
punked out).
can run pretty lean. I do not know if these motors will go
diesel at high cylinder pressures and stoich, or not. If you
do not diesel then theoretically you can run as lean as you
like (though the EPA has another opinion on that).
Flame speed vs mixture falls off at both lean and rich
extremes (there is also an upper and lower explosive limit
for all combustible mixtures). So you might be able to run
insanely lean and still not detonate, although this is not
going to be good for power or economy as the charge is
punked out).
01-18-2007, 02:27 PM
#7
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Originally Posted by marthastewart
John, you said that people do that for better MPG. Is that possable in a closed loop, or I would need to tune for SD, and get rid of the NB02?
