rtc113

I've got a 2011 RS. I put a Sharkwerks pipe on it 1,000 miles ago.

I got a CEL the other day complaining about one of the cats. The dealer swapped back to the stock exhaust to see if they could warranty the cat.

With the stock exhaust I'm not getting any codes.

I'm debating about whether to put the bypass back on (I really miss the sound) but I'm not sure if that's really the cause of the code or not.

Anyone had issues with this in the past? I searched and couldn't find much.

Also, the dealer mentioned the bypass pipes creating more vacuum which leads to RMS issues. Is that fact or fiction?

Thanks!

f4 plt

I've had Sharkwerks center muffler by pass on my 2011 GT3 since new and never had any codes

abcut973

I don't think the bypass was the root cause of your issue. O2 sensors are way before it. Did the dealer change your cat?
As for the RMS i'm curious to know the answer.

rtc113

No, the dealer didn't change the cat. The code went away with the stock exhaust back on. I figured I'd drive it for a bit stock and see what happens.

abcut973

What was the fault code?

RobT 394

Doubtful it was the bypass. There are 4 O2 sensors on the car, two before and two after the cat. Dealer needs to give you the codes as it will tell exactly which one is off, or if it is something else like the gas cap causing the CEL.

Track exhaust on my car for 4 years now, never had a CEL.

Snowboarder54

I have over 93,000 miles one my Sharkwerks bypass, stamped #4, and have never had an issue! Something is very strange here.

Snowboarder54

Like I said, I've had SW bypass for over 90k miles, no cell and no RMS. I think if I were you I would be searching for a new dealer.

rtc113

Thanks for all the feedback.

The code was P0420.

Spyerx

Highly unlikely it is the SW as those are cat efficiently codes and the SW bypass is after the cat.

Step 1 is to swap the post-cat O2 sensor left to right and see if the error reappears. And if it does which bank - it will move banks if it is the O2 sensor, in that case replace the bad O2 sensor (post cat sensor).
Step 2 is if the same code and bank gets flagged, most likely it is your cat, replace it.

These cats do wear out...

blackoutz

Im installing my bypass this weekend and hope it does not create a check engine light.

r6elmo

how many miles on car? it could be you have an issue with the cats or another part of the system and having the bypass on causes it to be the minor item that puts it overboard with the increased flow. Many have run the bypass for lots of miles without issue.

rtc113

The car has 11k miles.

I don't think the bypass has anything to do with it but for some reason they won't warranty the cat with the bypass installed.

So, now I'm just driving around to see if it comes back on. If it doesn't show up in 50-100 miles I'm just going to re-install the bypass and pay out of pocket for new cats if I need to.

audipwr1

I have my complaints about some of these bypasses - but they shouldn't effect cat performance whatsoever