Currently I'm running Stock Catted DP to right past the flex pipe (before 2nd cat), and from there hooks up to my 2.5" Piping (2nd Cat removed) to a Magnaflow Resonator and back box out the back. Wanting to open up flow more... I'm considering the OBX Catless DP. Read lots on it, for the money it can't be beat imo. I was out the door for under 350 for my Magnaflow system, and I am plenty happy with it, as I really only enjoy the sound of a JCW exhaust more than mine.

Anyways, living in MA, we have emissions every other year, and to be quite honest, living in an Apartment right now, it'd be quire the hassle to be swapping out my DP every other year just to pass emissions. That, plus the smell, etc, I think I'd rather just have a high flow cat in place and call it a day. Thus, I was looking at Magnaflow's hi-flow cats and seems like I can source one for right around $80-100 for a 2.5" In/Out, as thats the pipe sizing of the OBX. I'll weld it in on the straight section of the DP, near where OEM would have it, and my RMW tune will be able to remove the CEL. Let it warm up nicely and it'll pass inspection without skipping a heart beat.

In addition, it'll definitely be much free-er flowing than a stock cat.

In the end, this'll put me in about 175+80-100$, so we will say a $250-$300 range (Most other catted dp's are about 500+ iirc). Depending on if I decide to use the OBX piping to weld it up to my resonator back, maybe I'll fit in some flanges for easily disassembly if need be. I'm hoping the gasket between the OBX mid pipe and downpipe would be sufficient in place of a flex pipe? I don't think I'd want to reuse the OEM flex pipe as diameter there is going to be restricting to the rest of the 2.5" system.

Thoughts??

 

Just curious, why weld it to the DP? Why not put it where the 2nd cat in non-JCW Coopers is normally located, just after the flex pipe and before the resonator?

Otherwise, a good idea. I'm curious to see if this works out well since, as you mentioned, aftermarket catted DPs are expensive.

 

The 2nd Cat location isn't monitored, and emissions in MA don't use a sniffer anymore on newer cars, they read CFM's via the OBD II. So even though the O2 sensor reads beyond limits acceptable by the car (eg throws a CEL), its still within limits of whats acceptable by the gov't, which is how magnaflow gets away with street legal high-flow cats.

So to answer your question, the O2 sensor is on the DP.

 

It's hit or miss with aftermarket cats on how long they will last and how well they work...especially magnaflow ones.

Not worth the trouble in my opinion....

just....go....catless....

Or buy a catted akrapovic if you must...

 

Haha Blake, I knew you'd chime in eventually with the CATLESS statement =p
My brother ran 2 Magnaflow High Flow Cats on his B6A4 for 4 years withohut an issue. The N14 will probably go before I reach that point. HA

 

If you have vehicle inspections/emissions checks it is not worth playing the cat/no-cat game. You don't have the time or tools to screw with this banter. Keep your exhaust, get a bigger intercooler, and ECU tune, and be done with it. Don't let the small torque gain you would have got with a downpipe haunt you.

 

Now there's a true statement!

 

But the high flow cat passes inspection... I'm not going cat less. And I have all the tools and time, I'd be doing the install myself, I have access to a lift and welder, it's just not in my wanting to swap back every other year, as corrosion and rust playing into it will not be worth the effort to swap.

And I'm tuned, more dealing with the boost cuts still. The dp is because it's next on my list, not because Im dying for the few more ft lbs