How does FI compare to NA at high altitudes?

[NSX_GTR_LM]

I heard somewhere that Forced Induction is not as effected by high altitudes as a Normally Aspirated setup, is this true? The argument was that since the boost is regulated, the car will still run on the 6 or 8 or whatever PSI it is supposed to, partially negating the altitude effect. Will FI perform better than NA at high altitudes?

[oldster]

Yes it is effected, but since you are creating your own atmosphere it is not as severe as in a normally aspirated motor.

[NSX_GTR_LM]

Thanks oldster, i knew it would be affected, but it is not AS affected according to you. Thats what I thought too. Gracias.

[oldster]

No problem. :)

[Jesse IL]

A carburator has no way of adjusting its mixture the way fuel injection does (by reading the O2 sensor). Carburated engines will run rich at high altitudes because there isn't as much oxygen in the air. My bike which was jetted to run in Chicago (elevation 500ft) ran very rich and was down on power in Colorado (evevation 5300ft).

[loudceli]

I've heard that an N/A will lose approx. 4% per 1000ft. and an FI will lose approx. 2%(Don't know how accurate this is) All I know is that here in Colorado, I've seen stock WRX's run high 14s all day and I can only manage to pull low 16s(not just my driving either, although I'm not perfect and could probably hit high 15s with a lower 60ft, all other N/A's are really affected). Another example is Cobra's only pull mid to low 15's. Like my sig states - ELEVATION SUCKS!