Ever since the addition of the catalytic convertor manufacturers have started to run things lean. Might cost a few bucks now for dyno testing but at least you can thrash it senseless with peace of mind.lol
If the curves look good and there's no flat spots you wont need the PC anyway. Then get it dynoed to see how it runs now. You may aswell get an extra sensor port fitted to the exhaust while your modding it. Its running without heading for a dyno to get some high rpm/load mixture reading done. Everything else was bog stock, including mufflers & ECU, and the bike ran heaps better.Īnd if your going to do trackdays I would definitely consider fitting one as the bike will be working a lot harder/hotter up there and its hard to get a feel for how I removed the cat from my 07 R1 and fitted an Akro Y -pipe. Once you start introducing more air that's when leaning out becomes a concern. In my experience slip ons are fine if you keep the stock airfilter. "Any condition that causes abnormally high levels of unburned hydrocarbons-raw or partially burnt fuel-to reach the converter will tend to significantly elevate its temperature, bringing the risk of a meltdown of the substrate and resultant catalytic deactivation and severe exhaust restriction."
Hence the need for Power Commanders and other tuning devices. This helps get the cat up to temp quickly and reduces emissions aswell. So adding some extra flow there doesn't make them run lean, generally it makes them run cleaner.See I was always told the opposite. Generally the manufacturers run the bikes a bit rich anyway, it helps with engine longevity / less warranty claims.
spending $ to get a full system for more power and not doing the fuel mapping = silly. That said, slip ons don't alter the flow much and as a result the standard fueling will generally be near enough to be "safe".Īnd yeah, full system is a bit different. Some/most car engines will retard timing if it detects knock (a lot of bikes don't though), but they don't auto-tune per se on throttle.Īn airflow measurement may increase but you're off into uncharted territory on the fuel map and the bike may get rich/lean depending on whether it is carb or injected and whether the injection uses MAF or MAP sensor, etc. To "self tune" via an o2 sensor, a wideband sensor is required - the stock one isn't good enough. As soon as you go near the throttle the engine doesn't use it.
The o2 sensor on production vehicles is used only when cruising and is for emissions purposes.
Exhaust oxygen sensors and the like have their purpose here.
Most modern engines will self tune to the new exhaust flow anyway.
My less than expert knowledge and experience has taught me that the general rule is there are no specific negatives or risks to running an aftermarket pipe as they are almost always going to be more free flowing than a stock pipe, so no risk of the bike running lean.
Other than that there was no effect on performance before the map was updated, if anything I imagined it actually ran slightly better on the standard map, plus the pops and crackles on the overrun being completely removed makes it a bit dull in comparison. The bike was running rich and crackled a lot more on the overrun, the dealer simply uploaded a map that stopped it running rich and disabled the exhaust valve sensor. The new bike's ECU is locked so you can't do it yourself. When I slapped a pipe on my Daytona I was told by the factory it was essential to have it remapped at my dealer to ensure the engine wouldn't be damaged.