SD tune
RIck
Again in SD mode:
MAP sensor: Measures the PRESSURE in the manifold. Your car doesn't care if the barometer is 29.92 or 30.50. Cold front, warm front does not matter. Pressure into the intake is measured regardless.
IAT: Measures the temp of the incoming air. If it's 10 below zero out or 120 degrees, the IAT is measuring this. So, temp doesn't matter.
Front O2's: Measure the exhaust to trim the preprogrammed fuel values.
The only time you really might need to make a couple "tweaks" on a SD tune, is if say, you're doing the Pikes Peak challenge, and thus changing altitude by THOUSANDS of feet. Then the actual O2 content of the air will differ from the extreme altitude changes.
Otherwise....no need to constantly retune. Unless it makes you feel happy
P.S. If anyone has doubts, do a search for RedHotSupras blog site. He has a retarded amount of info on this and has it all backed up with physics equations. It's enough to make your head hurt!



