I love my fabspeed 200 cell cats but am curious to know if anyone is running their cat bypass pipes. Do they sound much different or louder? Any performance gains? I've been looking for a set of used cat bypass pipes to no avail and am considering getting some new ones if I can't find used. I tried the muffler bypass pipes which almost cost me my marriage and my hearing.

 

Anybody? (crickets chirping in the background)

 

Are you running Borla mufflers?

I have been talking to a local shop about building a custom header back system, that gives me maximum power, and keeps the sound levels under most tracks levels.

 

Yes, I'm running Borla mufflers with X51 headers and Fabspeed cats. The Borlas are great. They sound a bit deeper than other exhausts I've heard. I added the cats/headers for more HP and volume but it's not obnoxiously loud. With the Borlas alone I had some drone but once I added the headers and cats the drone went away.

 

The muffler bypass with 200cpi is loud..did this when I had my 997S and went back to my Borlas. I think the setup with the cat bypass won't be to far behind as far as db. is concerned, you may end up getting marriage counseling. BTW, my wife refused to drive my car even with the AWE 200cpi cats, Borlas and X51 headers.

With the M3 I am keeping it more civil as she needs to drive this every once in awhile.

Dave

 

same here, wife forced me to put stock mufflers back. honestly I like it better this way now myself. all this extreme loudness is pretty childish imho.

as of cats bypass i guess it will require some ECU intervention to disable O2 after cats sensors and if one wants to run race like straight pipes with no cats and no mufflers then it is not going to be a street legal anyway, plus most tracks have noise limits this setup will not pass.

 

LOL...remember..only difference between men and boys is the price of the toys..

 

I want to keep the Borla mufflers on and just change from high flow cats to cat bypass pipes but not if that will make it crazy loud like muffler bypass.

 

I'd like to hear some opinions on this as well. The muffler bypass question has been answered ad answered well. What about his original question on race cats or no cats.

Thanks!!
Carter

 

Hey Gator,

I have cat bypass with FVD software. Cat bypass is much louder the 200 cel cats.

I had to remove my sport mufflers and reinstall the stock mufflers to get the sound back in check. Now it is a perfect combination of cup car loud when you are on it but tame enough when cruising around town or on the highway.

Im in miami if you are ever down this way.

dr

 

OK, so you were running X51 headers with FVD cat bypass and FVD exhaust and it was quite loud so now you are running stock exhaust with X51 headers and cat bypass. I'm trying to find a volume above where I am now but below muffler bypass levels. I think I'll try the cat bypass with the Borla vs catbypass with my stock mufflers. Thanks for the advice. Now I just have to find a set of used cat bypass pipes.

 

Hi im in the same predicament. I have upgraded fabspeed headers, fabspeed 200 cell cat and muffler bypass. There is way too much drone in the cabin. Would it be better to bypass my cats and put my fabspeed mufflers back on instead? Would there be power gains or losses?

 

Probably no change in power. I found headers and cat bypass worked best with aftermarket mufflers. Muffler bypass was too much but the cat bypass opened up the aftermarket mufflers just right.

 

I wouldn't do cats by-pass, extremely happy with the Brombacher headers & 200 cells cats setup. On the highway other drivers knows what coming while sound stock in city.

 

i tried cat-less crossover pipes with stock headers and stock mufflers. it was extremely raspy to point of sounding like a rice rocket. with x51 headers it might be different. I also lost allot of low end power.
It was also hard to breath at the stoplight sometimes.
you will need mini cats or ECU tune to turn off the O2 censors.