[s-cars] 3071 turbo & Pastore RS2 code question

djdawson2 at aol.com djdawson2 at aol.com
Tue Mar 21 15:47:51 EST 2006

That statement would be true if there were no means to correct mixture.  However, those means do exist.
1) The MAF measures the mass of air... thin or dense, mass remains constant... and that's one way the ECU determines the fuel requirement.
2) The ECU incorporates a barometer... which identifies changes in altitude, and modifies A/F R.
3) The ECU takes input from the O2 sensor... and also changes A/F R based on those readings.
Now, if we had an 034EFI system, installed and programmed it in a car at high altitude... trailered it to sea level and hit the dragstrip... THEN we'd have a meltdown.  Only one map (fuel,ignition,boost)... no compensation ability for altitude... no means to deal with denser air (not even a MAF).
This is why I have stayed away from standalone engine management.  Hap's car will be an interesting "test mule" to see how the AEM system can deal with it.  Regardless, I would still expect him to have problems when he goes to sea level... and substantial additional programming will be required to make it work right down low.
-----Original Message-----
From: Dave Forgie <forgied at ae.ca>
To: s-car-list at audifans.com
Cc: pkrasusky at ups.com
Sent: Tue, 21 Mar 2006 13:25:31 -0700
Subject: [s-cars] 3071 turbo & Pastore RS2 code question

The "fact" part was about air at sea level being more dense than say air in  
Denver or maybe even Connecticut and that for a given amount of fuel,  
this will result in a higher (leaner) Air/Fuel ratio at sea level.

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