2.5" DP's without cats, no catback. CEL elims not working.

**fourings06** · 01-19-2009 01:33 PM

Hey guys, I have an 01.5 s4 and recently did some upgrading. I purchased the Techtonics 2.5" downpipes without cats from JHM. When ordering, I figured it was an obvious good idea to get the VAST CEL eliminators. The downpipes are now on, and I am running them with no catback. My rear 02's are still throwing codes, and emissions is coming around the bend. Now for the time being, I am just running open dumps with no catback on, but when emissions comes around I plan to have exhaust on; whether I purchase the system by then, or just mock my stock catback up to the downpipes for emissions sake - either way I need to have a muffler sticking out the back, or they may realize something is up, especially since it is LOUD. My question is: do you think that the compression loss from not having catback on, could play a role with the cel codes even with the CEL defoulers installed? If not, how simple is it to remove your rear 02's and run the car without them. If that is the road I were to end up taking, what could be the issues? I can't imagine the defoulers were just a complete rip off knowing they work for many others on the zine. Thanks!

**highPSI-S4** · 01-19-2009 02:44 PM

I think it depends on the placement of the defoulers. Were are they located?, before the cat, or on the cat?

**infinkc** · 01-19-2009 03:03 PM

your not going to pass emmission with no cats unless they dont do a sniffer. you might have to stack another set of cel elims on.

**fourings06** · 01-19-2009 05:07 PM

they don't do that in MD unless your car is pre-1997 or a year around there. I just get a scan. So worst case scenario i think i can get away with just putting stock exhaust on to limit the sound and show a muffler, and wipe the codes right before I pull in. but I would like to get the codes to go away.