06-01-2015, 08:31 PM
(06-01-2015, 01:49 PM)ChipBeck_imp Wrote: Gentlemen,
I currently have 3 different exhaust headers for my CB11. One of them is a stock header with the catalytic converter removed. If I install it will the reduction in back pressure screw up the way the bike runs or cause it to run lean or rich? Putting on the Staintune with it's straight through pipe reduced back pressure as the stock muffler has two 180 degree changes of direction and after that my CB still ran fine (maybe better). Will going the next step and eliminating the cat be too much and require a PCV or a reflash? Does the cat have so little back pressure that the bike wouldn't notice? Just looking at it I think that cat produces quite a bit of back pressure but I don't really know. Anybody have some experience here?
Chip
Chip,
You need to put the setup you want on the bike and have a tuner dyno the bike and setup A/F ratio's, this will require a PCV. The bike runs better just above 13.2 A/F as shown on charts. A flash would only be helpful if a map was created for your bike, without your bike being present its a shot in the dark.
My bike had a full Yoshi, flashed with a stock PCV map, although it run much better than stock it was on the rich side. Plug readings showed it running a bit rich on the outside cyl. this could have been corrected by a good tuner. Also, a tuner can check your 10%-100% throttle responses.
I don't believe the CAT creates an enormous amount of back pressure on this bike, very little popping on decel with a full exhaust. (unlike a ZRX1200) Popping will start off throttle above 4500 PRM's and can be eliminated with the pair mod.
So to answer your question, the bike will run richer with a full exhaust with more HP, to optimize have it tuned.