2004-2007 Cadillac CTS-V Performance Mods Discussion, Exhaust Question for the Heavies... in Cadillac CTS-V Series Forum - 2004 - 2007; ...If I run straight exhaust from the headers(cut cats)but reinstall the sensors....what will the computer do???...
You will set codes for catalyst efficiency and maybe fuel trims. I've also seen this with some aftermarket catalysts as they are not as good at removing pollutants as the OE cats are. Your car will also be louder as the catalysts also act as a muffler of sorts.
Most shops will do a tune if you mail them your PCM and send it back to you, but that's not the same as dyno tuning the car. I think with that set up you NEED to take it to a tuner shop and have them do the tune.
Cats make a HUGE difference with noise. When I put flowmasters on my 5.0 I ran it with "open cats" instead of open headers for a little while, just out of curiosity; the car sounded pathetic. The two chamber flowmasters smoothed it right out and made it sound quite nice.
Needless to say, there will be an emissions inspection issue if you remove the cats...unless you plan to have a "track" setup and a "street" setup........
On second thought, isn't the LS6 a "ULEV" engine? If so, doesn't the computer have a catalyst deterioration test program, and issue an error code (and possibly a "limp home" mode) when the computer detects a cat failure? Or does the "tune" that you refer to address this issue?
Automobile(s): 2004 CTSV(killed), 2005 CTSV(killed that too). 2004 DTS.
Re: Exhaust Question for the Heavies...
I know nothing about computers but I figured that any sensor could easily be jumped out. I read the V gets plenty of air in but is restricted on the way out. So, I thought exhaust would be a good first project. BUT, the more I drive it the more I want to just leave it alone. Although, I like the way that 427 sounds on the 427 thread.