Secondary Cat / Resonator Delete

Yo all.

Been looking to get the secondary cat / resonator deleted but don't want to spend £800-900 for a xpipe.

I rang around to get a custom made and they ranged £135 - £260. Sounds good and worth a try.

Question is, I rang MIJ Performance and the dude mentioned that there is a sensor on the second cat and it may throw up a sensor error.

That's the only place that mentioned that it might have a issue, but he said he had an M3 himself before.

Is that true?

02 sensors are before and after the primary cats so should be okay with just secondary removed but wont gain power this way either.

It's okay, I'm not expecting power gain. I just want a bit more noise.

chriszeh wrote

02 sensors are before and after the primary cats so should be okay with just secondary removed but wont gain power this way either.

+1

Gutting out the secondaries and doing a OEM Exhaust Mod should do the trick for you. Here is a DIY (costs: free 90 free) for the secondaries, GL!

http://www.m3post.com/forums/showthread.php?t=457202

I haven't got the tools or skills to do DIY

I might go ahead with custom so I can keep the OEM one to put back one day or in case I don't like the sound. Don't want it too too raspy.

yeah i would keep the OEM as well. i have to pass emissions every 2 years so need to return my stock for the test which is coming up.

Eek. Will it fail emission test with secondary cat delete?

Thought it was fine?

no you should pass with secondaries removed. mine is an obvious fail because when they connect to the obd2 port it will show them that my sensors have been messed with to not send a cel.

Is there a sensor on secondary cat? Or did you mess with primary cat?

sylonien wrote

Is there a sensor on secondary cat? Or did you mess with primary cat?

there is no sensor on the secondary cat. i have no primary cats. so yes i messed with them.

I see.

Also heard that secondary cat delete smells alot? Trolling through the net at the moment to find more about.

no smell is from going full catless. removing both sets.

Can report myself that secondary cat delete doesn't smell at all.

But a tad raspy... maybe I should of kept the resonator in.