Hello all, I am new to this forum and I have a 2003 C4 Cabriolet. I am looking to get some more sound for the exhaust without breaking the bank at first. I am considering the fabspeed cat bypass pipes and O2 extenders.

I was wondering if anyone is running this set-up with stock mufflers and what your opinions are on the sound, also if there are any sound clips. (I did do a search but didn't come across any clips). I figure if it doesn't give me enough sound I can always go to the Fabspeed mufflers as well, but I figured I will start with one thing at a time. Thanks in advance!

 

I haven't heard this setup, but I suspect it will be quite loud. You might try some high performance cats in place of the stock cats.

Another good, inexpensive way to get some nice increased sound is the Fister D muffler modification. I did this to my C4S, and it sounds great. It adds a little growl without adding any drone. I've also heard that the Fister D mufflers sound very good with sport cats.

 

Hi 2300cc, if you go with the cat-bypass pipes and your stock mufflers, it will sound a little more aggressive but not too loud since the stock muffler cans are big and restrictive. The only problem with cat-bypass pipes is that you may have issues passing emissions in your state and you loose some low end torque without the cats. I would go with Sport cats unless you are tracking the car, so let me know if you have any questions and I can offer you a member discount on the part.
Thanks,

 

Alex,
Thanks for the reply. The car is going to be used on the street mostly, and as long as the O2 extenders keep the cel off I should have no problems with inspections. Thanks again!

 

My set up is Fabspeed X pipes cat bypass + Fabspeed muffler bypass. Very loud. "I" Like it like that. Most people don't but I do.

I live by the Police station about half a mile. Never got anything for it. Instead they wave at me.

But if you're more conservative then I would take Alex's advice.

 

Dyno , cat bypass :

 

Alex, what kind gain does X pipes cat bypass with muffler bypass put out, not 200 sport cats.

This one.

 

They have the wrong site. Link:



http://www.fabspeed.com/996_GT3.html

 

what do you mean?

 

I posted the dyno wrong because the site is' wrong.

 

If you run a straight pipe setup (cat and muffler bypass) don't you lose power at the low end, but gain at the high end? I've been trying to dig through posts but I can't find any examples.

Does anyone know at which point you start to gain power?

 

I believe the chart posted is correct for a cat bypass pipe, it is just labeled wrong within the chart. You can see the low end drop off in torque between about 2700-3500rpm. I'm sure Alex would know if this is definitely the correct chart.

 

OK I am going to jump in here with an opinion that is not always popular. If what you are striving for is a better sound for the car go don't go with the cat bypass but try the Fister D mod to your mufflers. This can be done for about the same price as cat bypass pipes and has several advantages. First it does not effect the low-end torque like cat bypass pipes will. And it will not effect the drive ability of the car as the O2 sensors will still be functional as they won't be modified. Or try another muffler set up, although they can be pretty expensive.

With the cat bypass pipes you are disabling the pollution control system on your car which IMHO is a bad thing, and you have to deal with the O2 sensors, CEL's and drive-ability. issues. . It is also strictly illegal for a street car and makes you subject to pretty onerous fines if you are caught.

 

+1 Dharn55

 

Someone has just put the original exhaust with cat bypass or fister d?