Dyno, tuning and altitude

[plongson]

Suppose one completes a build and goes searching for a tune. Is a tune done at sea level superior to one done at say 5000' if your riding area is say, in the middle (2500')??

Does it make any difference at all? I'm sure the numbers will be lower because of the altitude but will the ECM/EFI "adjust" when you come back down??

[kdietz]

I just had my bike dyno tuned at 5500' and I rode it home 1200 miles to my 650' elev. home.

Got 2000 miles on it and it runs perfect at all elevations.

[HDWRENCH]

2000 miles already sounds like you are having fun!!

[Hillside]

Originally Posted by plongson

Suppose one completes a build and goes searching for a tune. Is a tune done at sea level superior to one done at say 5000' if your riding area is say, in the middle (2500')??

Does it make any difference at all? I'm sure the numbers will be lower because of the altitude but will the ECM/EFI "adjust" when you come back down??

What about engine timing??
Scott

[lonewolf55]

Originally Posted by Hillside

What about engine timing??
Scott

Is it timing or afr? I look at the map I have in my bike and I have 1 degree more in the 80 column than in the 90,95 and 100 map columns at same rpm's. My afr table is in closed loop (actual of 14.45 with clb setting) at 80 map ( up to 4500) but drops to betwen 13.2 and 13 in the 90 and 100 map columns. In the past I've pulled timing at the higher elevations but I wonder what would have happened if I would have adjusted my afr tables?

[Hillside]

This may help explain some things.........................www.axceleratedmotorsports.com/Tech.cfm.
Scott