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Old 08-28-2013, 10:02 PM   #26
Super73
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Join Date: Nov 2007
Location: Bay Area, Ca
Posts: 2,841
Re: how do these look.

There are pros and cons to MAF and narrow bands.

MAF can be a restriction when trying to get the last few hp from combo.

Narrow bands always want to achieve stoich (lambda = 1) which lambda is set in the tune.

Being I run a big ring gap and a semi loose piston to wall clearance, I don't want the narrow bands putting me at lambda at idle and tip in (below 2,400rpm and certain KPA). I actually command a slightly leaner AFR than lambda to help avoid e85 getting in to the crank case with the blow by I have (due to ring gap). I shoot for 1.02-1.04 lambda in those areas (15-15.3 AFR on the gas scale).

One can tune very close to lambda based on the volumetric efficiancy table. But narrow bands do provide a little more resolution in between VE cells since a speed density tune averages fueling between 2-4 cells based on KPA and rpm.

If you see major elevation changes often, or huge climate changes where you live and daily drive said vehicle, narrow bands are good to have. If not VE alone can be just fine.
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------Motor---------------Bottle
60'---1.53---------------1.41
1/8---6.58 @ 105.92----5.87 @ 118.41
1/4---10.38 @ 126.97----9.24 @ 142.49
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