[zsapphire7]

Question guys, Is anyone running a catless DPs with stock exhausts? There are 2 pairs of cats on our cars from my understanding and one pair is on the downpipes. If this is the case then, how is it running with just 1 pair of cats? Do you get that nasty smell downstream or should those cats clean it up reallly well?

Thanks!

[JoeyFiasco]

Assumptions are correct. From what I read on several threats, one set of cats takes care of the smell. Now you get better performance if you remove the DP cats instead of the secondaries. Then there's issue of warranty and ECU tuning.

Originally Posted by zsapphire7

Question guys, Is anyone running a catless DPs with stock exhausts? There are 2 pairs of cats on our cars from my understanding and one pair is on the downpipes. If this is the case then, how is it running with just 1 pair of cats? Do you get that nasty smell downstream or should those cats clean it up reallly well?

Thanks!

[Mr. 5]

Originally Posted by zsapphire7

Question guys, Is anyone running a catless DPs with stock exhausts? There are 2 pairs of cats on our cars from my understanding and one pair is on the downpipes. If this is the case then, how is it running with just 1 pair of cats? Do you get that nasty smell downstream or should those cats clean it up reallly well?

Thanks!

They both help with emissions and both help with smell.
Terry's 335 has catless DPs with the seondaries in place.

If you eliminate the secondaries then you will not throw codes and you do not need 02 sims. If you eliminate the primaries, you will throw a code unless you get 02 simulators.

Eliminating the primaries will show better results since you are freeing up more air close to the turbo shich lets it spool much easier.
Do a search on 02 sims and catless DPs and go from there.
There's a bunch of stuff on this topic.