I have owned my 2012 MCS for about 2 month now, the previous owner had installed an Invidia catback exhaust on it. The exhaust as is sound pretty nice, but I think it could sound better. So I just wanted to ask you guys what downpipe/any other exhaust adds would be best to add on.

Preferably not throwing any codes, if that's even possible upgrading exhaust components...

Thanks in advance!

 

You install a downpipe and you'll be throwing codes, the only way you're not throwing codes is by getting a tune. Tuners can make it to were you're not throwing codes after installing a downpipe. You'll have to uninstall it every two years for SMOG.

 

What makes a downpipe throw codes though? Because a few that I have been looking at all connect right to the O2 sensor. Is it that there is more carbon coming through than would typically be allowed with a cat?

What else can I ad to get a deeper "throatier" sound out of my exhaust? I feel right now it's got a lot of bass to it but it sounds somewhat... airy i guess? Like it's hissing rather than growling...

 

Traditional Down Pipes and even those with a high flow cat do not clean the air, plain and simple.

Anything but a stock or high quality , high dollar 400 Cell per inch cat will give you a P0420 Cat insufficiency code, IE your cat aint working or working good enough.

There is no magic pill or magic spacer that works. MAYBE just Maybe if you got a DP with a 200 Cell cat and used a spacer it MIGHT not throw a code but doubt it.

The tune or can tool or Akro delete just masks the CEL , there will be a "NOT READY" for Cat in your OBD scan that will fail you for emissions testing. But the light can be turned off, just won't pass emissions.

 

That's not entirely true. How each state checks emissions varies widely. My 100cel Akrapovic high flow cat will throw a code but the Manic tune "disables" it and it will pass emissions testing in North Carolina.

 

My catless dp (which to me with stock exhaust is a great sound) will pass inspection here in nj with my manic tune

 

I recently picked up a clean unmolested 07 MCS. I have been looking for the last week at a few downpipes. The ones I have seen are 2.5"; are their any 3" downpipes on the market? I noticed that the downpipe bolt spacing is rather close and this is likely why I haven't found a true 3" yet?

 

Mine is supposedly 3" I never measured but it was very hard to get all three nuts snugged down

 

3" will lose some torque and gain some high rpm hp . I prefer torque myself but to each his own.

 

So for torque reasons alone, would it be wise to keep the stock DP? I mean my Invidia does sound way good by itself, I just want a nice clean growl rather than a really bassy/pop & burble mixed with a high RPM hissing.

However, the noise isn't worth a drop in torque.

 

The butt dyno didn't feel a drop in torque plus what the manic does torque wise is enough all I felt was a change to a beautiful sound

 

All the aftermarket downpipes will cause a check engine light without a tune or bypass of some sort.
I'd suggest the Akrapovic Downpipe as it always fits perfect, and has 100cel cat so it's not too loud like catless can be. Then get an ECU tune.

 

Go catless! Get a tune! Floor the pedal! Enjoy the smile!

 

+1

 

I'm running the same cat back with evolves decat downpipe and it sounds amazing. Exactly what I was looking for. It does throw a code but I'm planning on a manic tune within the next couple of months so I'm hoping that will take care of it.