I'm about to replace my exhaust (installing Random Tech Cats & Y-pipe & a Corsa Cat-back) and I was wondering if any of you guys had to adjust your settings after you changed your exhaust. I have heard everything from leave it alone - the PCM will make the adjustments, to lean the fuel, to richen the fuel. Any experience out there? I have a Predator, so I can play a little bit. <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />

Most likely you won't need to do anything. If you have not moded the MAF or I assume you have facotry manifolds, then the engine should adjust. Just do some scans after you do everything to make sure. Retuning seems to come in when you mod the MAF or change injectors. Even cams, heads, and headers, would probubly be adjusted by the factory computer if everything else (MAF and injectors) were stock (and idle speed was not a problem). Remember, the computer takes all its readings from the MAF and the O2s. If you start flowing more air, the MAF will sense this and the computer will make fuel and ignition adjustments with the help of the O2s. Its only when the MAF is out of calibration (ends, none calibrated MAF) and/or the injectors flow rate is different (change to larger injectors) that the computer runs into problems.

Chris