I just chipped my s4 and now im looking to put an exhuast.... I'm looking at the borla cat back with some high flow cats... does anyone have it on their car? Any ideas/opinions on whats the best sound for the s4 ? Also I hear about piggies a lot, whatare they exactly ?

 

i have borla and it sounds great... with some dp's it's even better!! piggies are stock dp's with gutted cats... if yuor looking to go stage 3 or higher- piggies aren't the best route since they aren't that wide.
btw borla is one of the cheaper catbacks since single 3".
check out youtube and search s4 borla, s4 exhaust, b5 s4 piggies, etc.. there are many many many vids

there is a before and after for a borla with piggies for u to check out on youtube

sound is a personal preference- awe twin 1 is louder and sounds great as well. one of a favortites on here lately is the fast intensions exhaust.

 

i would get teh awe twin 1

 

2x!

 

I have the borla, sounds great! but the fast intensions sounds amazing from listining to that nogaro blue on youtube with it.

 

True Dual > 3"

ASP and AWE are nice, somewhere theres a dual 2.5" for sale too

 

yeah i would do AWE twin 1 or a custom fast intentions

theres no other option!

 

^^ custom single 4" FTMFW!!!

I have been thinking custom 3.5" for a little while now.. and it's only a tiny bit smaller (surface area) than dual 2.5"
here are the surface area #'s squared
Dual 2.25" - 8.06"
Dual 2.5"- 9.88"
Single 3"- 7.07"
Single 3.5"- 9.65"
Single 4"- 12.57"

Dual is .23" squared bigger than the 3.5", but also heavier. Then the 4" just destroys all!

 

guys....its not all about surface area....you dont just want the biggest flow you can possible get. heres why (in short):

The small 2.7 will only move some much exhaust gas, especially when its first stop is to spin the turbos. Its all about air flow speed than it is mass. You want the air to be moving very fast, but be smooth. if you give it an exhaust thats made for much larger flow (like a 4") you are going to get a lot of turbulence in there. The turbulence is only going to cause an increase in backpressure. while some is good (like what you get from the turbos and cats), too much is bad. Basically having too large of an exhaust will cause a loss of power from your car. Its the same idea that having an exhaust on, even just straight pipes, is better than haveing no exhaust at all...

Why do you think companies like AWE, APR, and Borla dont make a 4 inch exhaust. The reason is its not nearly as efficient on these cars as a dual 2.25 or a 3in. If the a 4 inch exhaust was so great, dont you think more people would be selling them?

any questions, feel free to ask.

 

^^ it's also a lot more $$... 3.5" or 4" isn't practicalfor stock k03's, but once you get into tuned k04's, rs6's, and gt's.. then there is a need. Also, i beleive the k03 record holder (for the 1/4) was using 3.5"..

im going to find my thread on AZ about this.. it's a good discussion and a good read imo...

http://www.audizine.com/forum/showthread.php?t=196389