High-Flow cats which tune?

[89-TTA]

Was just wondering which I should use I have a 300 SRT8 with high flow cats and a K&N drop in filter. 93 CAI or regular 93? Dont know if the cats require more fuel.

[Mike_Levy]

Gotta go custom to turn off the rear O2 sensors. Otherwise she's gonna throw a code and check engine light. And ditch the drop in. Its useless. You'd be better off with one of the cheapo eBay intakes then just a drop in. The drop ins have the exact same surface area as stock. There is no advantage to it. Conicals have more surface area of a less restrictive media.

[Mike_Levy]

You need a custom tune. Its against EPA regulations so they had to remove that option from the tuner.

[89-TTA]

I know the drop in does not require the cai tune, but I have heard the cats gain 9-15 hp on the dyno. This makes me think I need more fuel thus I was wondering if I should use the 93cai tune wich I believe adds more fuel. As far as the O2s I am currentlly using plug foulers that seem to keep me from getting codes. Thanks.

[mikel]

Yeah, use the CAI.

[Charger250]

Probably going to need to add more fuel than that, only a wideband O2 or ideally a custome CMR dyno based tune will properly tell you this.