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YOUR RESEARCH'03 996 C2 - Cats going bad
Leading reported evidence
Install speedtech catless x-pipe
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Leading evidence: 'Install speedtech catless x-pipe' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check any pending error codes' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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So my cats are starting to go bad and I've been looking around for the best deals on x-pipes.
Looked at all the usual suspects but then came across
Evasive Motorsport
offering x-pipes for $855. Seems really legit, right? lol. Does anyone have any experience with them or their products? Seems like it's either a rip-off or a new company looking to get their products out there.
My exhaust rattles and sounds terrible below 3,000 RPMS... I have had two mechanics that think my cats are going bad, however I just passed emissions with flying colors...
Just curious, how do you know your cats are going bad? I also have an 03' with 72,000 miles
Doesn't have to be from a bad converter. The noise can be from a loose heat shield or something else loose and making contact with something it shouldn't.
Have you checked for any pending error codes?
My Boxster actually had a loose converter brick -- at the end it knocked when cold and buzzed when hot -- occasionally it would trigger a CEL and error code P0430, but the car could go months without the error code showing up. And the car/engine passed smog a number of times too.
I just installed a SpeedTech Catless X-Pipe. It does smell a bit, but my eyes don't water unless I close the garage door on it.
Noise wise - I've got Sports Exhaust mufflers, and at "city" speeds and low rpms, it's hardly any louder (at least inside the car).
At WOT in a tunnel......... it's devastatingly loud above 5k revs.
One of my cats started rattling about 3 months ago on my 03 4S with 64k on it. Savin up for fabspeed 200 cell sport cats... bout $2k for those, better than paying $2k for ONE OEM cat from Porsche. Cannot wait cause the rattle is so annoying.
To check if your cats are going bad, compare the voltage of the pre-cat oxygen sensor to the post cat sensor reading. The pre cat voltage should follow roughly a sine wave and the post cat sensor should be close to a straight line. If the post cat sensor starts to show a sine wave, then you have a bad cat.
I just passed emissions and don't have to get them for another 2 years... may just be worth going catless for 2 years until I have to swap my cats back in again... I have gone this route with a few of my other cars. At the 2 year mark it just gets slightly annoying changing them out before and after inspection.
The Evasive system that you linked looks interesting because it has a valve that varies the output of the X pipe. I have never heard of this manufacturer or anyone using them although that means nothing. From the photos the welds look very good. I can attest to the quality and workmanship of the SpeedTech X pipe. I've run this pipe on my 996 for over a year now and just love the way it sounds, especially at higher rpm's. The quality and workmanship is top tier and the price is very attractive. I've never had a CEL using this pipe
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