kevdeed

Hey guys, looking to do a secondary cat delete on my c63 but just holding back because of the smell issue. Can you guys give your thoughts and experiences on this ? Thanks

INS1GNIA

If you don't have other modifications, there won't be any smell issues.

Panzerbiscuit

I have a res delete, secondary cat delete and running 100cel primarys. I don't have any undue smells.

In any case, in the words of the Italian stallion, Rocco Sifredi "itz only smellz"

bumsu

sorry what are "100cel primarys" and why do you need them.
i heard the secondary cat has no sensors on it.

Slow_c63

iTrader: (1)

Sounds like he removed the stock cats, which restrict exhaust flow, then added “high flow racing cats” - at least that’s how they’re advertised. Which equals more flow, less restriction.

Downside is, 100 cell cats longevity is very short. They will burn out very quickly on our cars. The stock cats are rated at 400+ cell, I think.

Panzerbiscuit

Secondary cats are unmonitored, as in they don't have an O2 sensor on them. Which is why i paid someone to remove them. As they served no purpose other than stealing my decibels and power.

primary cats are monitored. I replaced the oem cats with "hi flows 100 cel cats" as mentioned. These are way less restrictive than stock. Theoretically, i should make more power. It does make my car a lot louder, and spit more "soot" from the exhaust which collects on my bumper 😅

I currently have a CEL from my headers and 100 cel cat installation which will need to be tuned out, or failing that. I'll need to add an O2 extender bung to try and trick the ECU.