2ndary Cat delete

[BLACKnWHITE168]

Secondary cat delete to go with my resonator delete and OEM Mod. Can feel a slight better throttle response. Sound: a loud deep raspy sound, intoxicating at 4000 RPM and up. Not everyone's cup of tea.

[inTgr8r]

You kept the primaries????

The downside to completely CATless is the smell.
My car is currently CATless and I love the setup except for the untreated odour.
My secondary CATs are going back in.

[Todd0131]

I recently went to catless xpipe and way to stinky. Def going to put in some cats

[Ngilbe36]

Originally Posted by inTgr8r

You kept the primaries????

The downside to completely CATless is the smell.
My car is currently CATless and I love the setup except for the untreated odour.
My secondary CATs are going back in.

Somehow, I am not bothered by the smell. Catless for life!

[thetastelingers]

I did the same thing. I kept my primaries as well.
Only reason is I hate the smell.

[M43S7RO]

Ditto, completely catless. Doesn't bug me enough to give back the gain of removing them.

Originally Posted by Ngilbe36

Somehow, I am not bothered by the smell. Catless for life!

[eatsleepboost]

I have yet to change my x-pipe and don't see them in the pictures but where are the bungs for the o2 sensors? I'm guessing there is 2 pre-primary cat sensors and 2 post primary cat sensors.

This would also mean that the secondary cats are not monitored as it has no o2 sensor after it correct? I have read these cars only have 4 o2 sensors.

[Todd0131]

going to put mine in the secondary position. I don't mind the smell. My 8yo kiddo is bothered by it. Plus hopefully it will get rid of a bit of rasp.

[BLACKnWHITE168]

Originally Posted by inTgr8r

You kept the primaries????

The downside to completely CATless is the smell.
My car is currently CATless and I love the setup except for the untreated odour.
My secondary CATs are going back in.

Just the secondaries only I left the primaries cuz I wanted some back pressure and avoid the smell. With resonator delete and OEM Mod it’s already pretty loud but no drone.

[BLACKnWHITE168]

Originally Posted by eatsleepboost

I have yet to change my x-pipe and don't see them in the pictures but where are the bungs for the o2 sensors? I'm guessing there is 2 pre-primary cat sensors and 2 post primary cat sensors.

This would also mean that the secondary cats are not monitored as it has no o2 sensor after it correct? I have read these cars only have 4 o2 sensors.

Correct, all O2 sensors are in front of the secondaries, so it won’t throw codes. As long as the primaries are stock you’re ok, if you remove them you’ll need a tune for the warning lights.

[BLACKnWHITE168]

Originally Posted by Todd0131

going to put mine in the secondary position. I don't mind the smell. My 8yo kiddo is bothered by it. Plus hopefully it will get rid of a bit of rasp.

I don’t think the secondary cats affects the rasp as long as you keep the resonators. Mine are gone but I like the sound!

[Todd0131]

it has resonators in the x pipe already, just 2 though.

[BLACKnWHITE168]

Originally Posted by Todd0131

it has resonators in the x pipe already, just 2 though.

I think if you keep them the raspy sound isn’t that noticeable.

[Todd0131]

Oh I’m not getting rid of them. It has a bit of rasp low in the rpm now. Hopefully this will help and quiet the system down a bit. Was perfect with just test pipes. But got kind of loud wih the Bimmerwor,d xpipe. Cats arrive today so we will see. Haha

[Dave07997S]

Originally Posted by eatsleepboost

I have yet to change my x-pipe and don't see them in the pictures but where are the bungs for the o2 sensors? I'm guessing there is 2 pre-primary cat sensors and 2 post primary cat sensors.

This would also mean that the secondary cats are not monitored as it has no o2 sensor after it correct? I have read these cars only have 4 o2 sensors.

The secondary 02 sensors are behind the primaries,not in the picture.

[Teufel_Hunden]

What would be the best way to go, considering 02 sensors, sound, increased HP and smell? Primary or secondary CAT delete (in lieu of going completely CATless)?

From what I've read, it sounds like removing the secondaries is the way to go, everything considered.

[BLACKnWHITE168]

Originally Posted by Teufel_Hunden

What would be the best way to go, considering 02 sensors, sound, increased HP and smell? Primary or secondary CAT delete (in lieu of going completely CATless)?

From what I've read, it sounds like removing the secondaries is the way to go, everything considered.

There are many thing to consider.

If you got the time and money best way would be Test Pipe, retune, high flow cats with resonators, and OEM mod or axel back exhaust. Primary cats have the most cell 400 I believe, by removing that you are getting much more exhaust flow. This X pipe set up limits the smell while moving air along, OEM Mod or Axel back exhaust still gives you back pressure for low RPM acceleration.

If you want the best bang for your buck, then you could go my way, keep the primaries no retune needed, cut off the secondaries and resonators on the X pipe for straight pipes, and OEM Mod for sound but still some back pressure. You get some HP gains, the nice low loud sound with some rasp in high RPMs, minimal smell unless idling, and no fix it ticket for city driving.

If you want loud obnoxious, raspy, and bad smell just straight pipe everything. Acceleration will go soft at low RPM, but once you get going you'll be a bat out of hell. 200-300km pulls would be the best with this setup. Works well also if you have a Supercharger, but I recommend an exhaust or ear plugs

My two cents....other people may have different opinions.

[Teufel_Hunden]

Originally Posted by BLACKnWHITE168

There are many thing to consider.

If you got the time and money best way would be Test Pipe, retune, high flow cats with resonators, and OEM mod or axel back exhaust. Primary cats have the most cell 400 I believe, by removing that you are getting much more exhaust flow. This X pipe set up limits the smell while moving air along, OEM Mod or Axel back exhaust still gives you back pressure for low RPM acceleration.

If you want the best bang for your buck, then you could go my way, keep the primaries no retune needed, cut off the secondaries and resonators on the X pipe for straight pipes, and OEM Mod for sound but still some back pressure. You get some HP gains, the nice low loud sound with some rasp in high RPMs, minimal smell unless idling, and no fix it ticket for city driving.

If you want loud obnoxious, raspy, and bad smell just straight pipe everything. Acceleration will go soft at low RPM, but once you get going you'll be a bat out of hell. 200-300km pulls would be the best with this setup. Works well also if you have a Supercharger, but I recommend an exhaust or ear plugs

My two cents....other people may have different opinions.

Thanks for the feedback, I appreciate it. I'll continue to do some research and see what others have done and the pros/cons associated with each method.

[Mvy]

Originally Posted by M43S7RO

Ditto, completely catless. Doesn't bug me enough to give back the gain of removing them.

My dyno results were the same between 200 cell high flow cats and catless.