It is possible that you lost some back pressure with this new free flowing design which will will affect the low-end, but your high-end should kick *** now.

 

I can say it definitely and literally gives a kick after 4.5K RPM now, to 7K I would say.
I am concerned with amount of smoke it produced during first start. It may have clogged sensors... Hopefully it will burn out with time. Will see.

I wonder if new cats have burn-in period as well or are they indifferent to any initial burn-in? Kinda funny - it is first time I use brand new high performance exhaust, somehow all the times before I only had used ones.

 

The cats don't really burn-in, but your new mufflers will and they potentially will get louder over time.

 

I wouldn't worry about this either. The tolerances on the sensors are extremely small, if there is any problem you'll get a CEL.

 

Would definitely go for the ECU reset. I've always had funny smells as new exhaust burns in on the car. Sounds hot to me. Perfect little snarl. The non-S is quite a bit more subdued than the S, so it's really a nice improvement for you.

 

Well, if ECU reset will not change anything I will try stock cats with new mufflers. I am just concerned now how will it fit - stock cats pipes may be bit too short for fabspeed mufflers i afraid. Will see. I need now to depress 2 broken bolts from each of stock cats, it may some take time...

 

Is there any way to measure/describe/convey how much louder this setup is than the car with just Fabspeed mufflers - on a 997S? This design seems very interesting, but I don't want to end up with an unacceptably loud car. Love the Fabspeed mufflers on my cab though but need to keep my car civilized.

 

It is quite laud, but not nearly as loud as with direct pipes with no muffler. Sound on idle is perfect. But going into 3K area from start it actually feels louder than later going into 5K-6K area from 3K and that annoys me a bit as I do not want to impersonate Harley in low RPMs - I would like it to roar at 6K, but not so much in lower range.

I will need to drive a bit to decide if I do indeed like (can survive) this constant bass roar in my ears starting from 2.5K rpm or not. Emotionally it feels OK. But I think I got a slight headache after 30 miles roundtrip yesterday. My kidneys can definitely feel the sound now. May be I screwed in mufflers too tight, not sure. Also, those metal rods now bended across mufflers and touch them so vibration from mufflers goes to car rear fenders, may be that adds up too. I will need to work on all that next several days.

My most concern is how car goes now - ECU definitely was back on timing, as I found everybody get this, so if ECU reset will not restore that 'kick' car had before I think I may need to revert to stock cats. Cattman stated in his post his car got to normal in 100 miles. I wonder if it was actually him getting used to it or car getting back.

 

Sounds like its pretty loud. OTOH, seems like you've got to get those bumper struts straightened out to get a proper test. The vibration you cite might be caused by the struts contacting the mufflers and transmitting it to the body. I haven't replaced my support struts yet, but have to. Just not looking forward to the bending process. Sort of a weird design feature of the Fabspeeds.

 

If you run on stock cats - how did you put fabspeed mufflers on - I have a feeling mufflers pipes are shorter by 2-3 inches than stock ones? Did they reach your cat`s pipes or did you have to put a connector pipe with extra clamp?

Of bumper struts - to bend `em is the only way and it is a pain in the ***, yes.

 

Do I understand this right? With the Fabspeed mufflers or the this cat setup that the fenders struts then contact the mufflers?? That's not what I call a bolt on setup.

utkinpol - I thought the sound clip sounded great. Quiet at idle, but a nice deep tone once you got off idle. Seemed pretty similar to a Fabspeed muffler only change. Also have to factor in that I hadn't heard this in on a non S. The stock S exhaust has much more character than the non S.
as mentioned, tone is a personal preference. Rasp, deep tone, wail at WOT, these all seem to be achievable, but with different products.

 

I had just Fabspeed Max Flow mufflers on my 06 and 07 Carrera S. To me they were not loud at all. The car sounded just right. They decibles is would say are no louder than the Porsche Sport Exhaust but with the Fabspeed mufflers they are not as raspy as the PSE.

I listened to a lot of mufflers back then before I bought the Fabspeed mufflers and I thought they sounded the best. Plus they are very well built.

I hope this helps!

 

Well, do you also have 200 cell cats?
Anyway, I did ECU reset and it worked just as prescribed - sluggish first 20 miles, than on 25th mile it woke up, drove 40 total, car pulls like crazy now in 4K-7K area, 3K-4K area probably very close to what it was, I can live with that, torque on 3rd gear in 2K-3K is almost non-existent now, much less than it was before but it compensated well by increase in 4K+ area.

Roar is above adequate to my taste but actually quite manageable, I drove my mother in law today and we were able to have a normal conversation most of the time. So now the ultimate decision will be to have my best half`s opinion this weekend. Will see.

upon arrival I checked exhaust pipes - seems like a bit of gas leaking from below that bracket that connects muffler and cat pipes and nuts there are tightened to maximum, that is unpleasant. Will need to do something with it...

 

The mufflers will work just fine with factory catalytic converters, you just use our extention pieces with the clamps. If you decide to run it that way, let me know and I will send those pieces to fit up with the factory cats. As for the mufflers, they will get a little more sportier after the packing inside them burns in and settles, but you will not have any issues with the 02 sensors. They will adapt as you drive the car more.
Thanks,

 

So, Alex, that low bass roar at 3K or so when engine is under load - is it mostly due to cats or due to mufflers design? I also feel more vibration than usual now, not sure what the heck... It probably because rods are touching mufflers, not sure. Overall you got great design for this system, but those rods are definitely a weakest link.

I wanted to avoid cutting anything, if possible, but as it seems it will be tricky to fit stock mufflers with xpipe cats. I figure there is no adapter for that - the only way is to cut?