Hi all
further to my "catalytic convertor" thread concerning my 08 ZX 14, I am now wondering about the secondary exhaust ports and their effect on skewing the readings of an exhaust gas analyzer.
the 06/07 models has secondary air exhaust ports feeding fresh air to the exhaust leaving the head, and supposedly helping further burn/lean out the exhaust before it got to the two catalytic convertors, one in each muffler.
for 08 Kawasaki added a third Catalytic convertor, situated in the collector, made the collector 75% larger in diameter, and increased the size of the secondary air exhaust ports by a further 20%. I am guessing the larger air exhaust ports were to try and help out in reducing the load on the new third cat so much closer to the exhaust ports, by leaning out the exhaust as much as possible before the exhaust hit the cats.
having now removed all three catalytic convertors on my 08, and installed an O2 bung in the collector for the autotuner, it seems to me that mapping for a particular air/fuel ratio using the O2 sensor and the autotuner is STILL dealing with false, artificially lean, exhaust data, arising from the fresh air added to the exhaust by the secondary air exhaust ports. That HAS to be the case, if Kawasaki has taken the trouble to enlarge the size of the secondary air exhaust ports for the 08 model year......
it appears I am still not going to get accurate air fuel readings even from a wide band O2 sensor in the collector, cats removed, unless the effect of the secondary air exhaust ports are either taken into account somehow, or the secondary air exhaust posts are plugged/closed off somehow.
does anyone know how much impact the secondary air exhaust ports have on the exhaust gas mixture reading downstream? Is there a "cheater" factor I can use in setting a fuel/air mixture, say setting the fuel/air ratio a few ticks richer from optimum calculated to take into account the effect of the adding of fresh air to the exhaust stream before the exhaust gets to the O2 sensor?
or has anyone closed off the secondary exhaust ports, if so how, and what was the result? Is there any downside to plugging the secondary air exhaust port? (other than increased emissions?)
Thanks
Paul
* Last updated by: laverda1200 on 8/27/2009 @ 1:16 PM *