If the bike was tuned at a lower altitude, absolutely. The ECM can only compensate so much and you are likely past that point.'11 NightRod Special... K&N air filter, no airbox lid... currently, 2-to-1 Danmoto slip on exhaust, going to straight pipes. I usually ride all the time between 6500 - 9000 ft. Is a tune really needed since I'm doing all of my riding at altitude?
To a point . Map sensor will do it's thing but without O2 sensors the bike will run much richer, and the same if PC3 is used. There is a max amount of compensation, however the op is within this range since he should be close loop in the tune. Open loop as in earlier v rods won't have O2 compensation for fueling and will run much richer at elevation. Same as a carb, if in open loop.IIRC, the ecm essentially takes a "snapshot" of barometric conditions whenever the bike is started and it uses that snapshot until the next time the bike is started.
So, if you were to (theoretically) start the bike at sea level and ride straight up to the top of a Fourteen'er here in CO, you might have issues.
In the real world? Don't worry about it.
https://de.wikipedia.org/wiki/LuftdruckStarting at sea level, how much affected would afr, open loop be for every 2000ft elevation? Anyone?
Nah, not my Sporty, but looks crazy cool.
You need to retune the ECM when changing anything in the intake or exhaust that affects the VE (pumping efficiency) of the engine. This includes things like camshafts, velocity stack length, exhaust pipe geometry, displacement, etc. Changing to lower restriction air filters alone can be handled by the MAP (manifold absolute pressure) sensor. This MAP sensor also compensates for altitude (and weather) changes, as Jan-Dirk mentioned in Post #4. I don't see how riding at high altitude eliminates the need to correct for VE changes. The VRSC fuel injection can't be compared to carburetors (or older mechanical injection systems) that don't adjust for atmospheric pressure.'11 NightRod Special... K&N air filter, no airbox lid... currently, 2-to-1 Danmoto slip on exhaust, going to straight pipes. I usually ride all the time between 6500 - 9000 ft. Is a tune really needed since I'm doing all of my riding at altitude?