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Old 02-06-2013, 11:02 AM   #29 (permalink)
beatr911
Master EcoModder
 
Join Date: Feb 2008
Location: West Coast, USA
Posts: 516

B2300 - '96 Mazda B2300 SE

Focus - '05 Ford Focus ST

The red car - '00 Honda Insight
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To keep perspective, for at least my experiment, I will not be re-engineering this bike much at all. Probably just changing valve and ignition timing and possibly some jetting changes with O2 sensor information.

The manual says static compression is 10.2. Dynamic compression at totally stock timing is about 8.4, retarding one tooth on the intake cam drops it to ~7.3 (if I remember right, my data is at home). From what I've read, dynamic compression of about 8.5 is about the max on pump gas. My 8.4 runs well on regular grade gasoline.

So, to take advantage of the lower compression, I'll use advanced ignition timing, lean carburetion, and the hottest intake air I can muster.

The key for this experiment is to find the balance between reducing dynamic compression and intake reversion. Gain in one, lose the other. Finding the correct balance that is biased toward fuel economy is the goal. As much fun as it sounds to tinker endless nights optimizing this engine, I do not want to incur too much work. I would like this to be repeatable by others, or have others at least use this to some sort of advantage.

Oh, yeah, no big hurry as I ride a vanpool to work and am not on the bike as much anymore. Please be patient if you are eating popcorn while reading.
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