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[huntnjim]

Looking for expert opinions , I live at 7600 feet and one of the local tuners shop is at 6000 feet. We ride through out the mountains from 4000 to 12000 over some of our passes. If I take my 110 to 1100 or in that area for tuning on a dyno will it affect where i live at altitude?
I was told when I did this to my Z06 that it would not matter that the ecm will adjust. However when I had it retuned at altitude I gained HP and TQ. Not sure if it was tuner or fuel/air adjustment? Apprecite know tuners like Doc and Steve to chime in for direction.

[Steve Cole]

The ECM will adjust to a point but typically if you have the same tuner tune the bike at sea level and at altitude there will be a difference. Some bike you will never notice it while others with different builds you will.

[TxDrifter]

It should adjust.  That is what the MAP sensor is for.  It provides the information to the ECM so that it can calculate air density and air mass flow rate.  All engines lose horsepower as they rise in altitude.  I think the formulas is: 

HP Loss = (elevation x 0.03 x horsepower @ sea level)/1000

I think that is an estimate based on a 3% loss of oxygen for a thousand feet.  Based on that, with the change in numbers you are listing, it will be noticed.  I know with my bike that has almost 100 HP at sea level it is estimating an 8000 ft change it should see a 24 HP loss.  Pretty significant.

[huntnjim]

The ECM will adjust to a point but typically if you have the same tuner tune the bike at sea level and at altitude there will be a difference. Some bike you will never notice it while others with different builds you will.

Ok just to be clear if you tune the bike at low level and drive or trailer back to 7600....ride the bike for several hous the ecm may not adjust correctly for maximum performance?

[TxDrifter]

Ok just to be clear if you tune the bike at low level and drive or trailer back to 7600....ride the bike for several hous the ecm may not adjust correctly for maximum performance?

Only if it does not utilize a MAP (Manifold Absolute Pressure) sensor and ECM, or you have disabled or bypassed the sensors.  The sensor determines air density and flow and the ECM uses the data to adjust the air/fuel mixture and timing for the conditions. 

[Midnight Rider]

Ok just to be clear if you tune the bike at low level and drive or trailer back to 7600....ride the bike for several hous the ecm may not adjust correctly for maximum performance?

Just make sure your tuner does not take the bike out of closed loop operation all the time...some old school tuners will do that.  While it will still adjust to some extent, you will not have the full capability of the ECM if taken out of closed loop operation full time.

[SteveO]

Turbocharge it and that will take care of the problem !!

[Hotrod50]

My stage 2 09FLTRSE3 runs great at 1500 feet here in Kansas, but runs like crap when I go to Colorado and go up to 10-12,000 feet.  Don't think I can do anything about it though.