Gathering Info regarding to the exhaust ( s4 v8) about to start my custom one.

Hi

Im about to start the 2 step for my s4 , the cat-back , coming from the turbo “club” doing this its not a difficult task , but here on the v8 its got a little more complicated , basically my question its about the X pipe , The basics says the x pipe needs to be as close as possible to the headers , I have seem a lot of pics of a very well made setups on this v8 ,but I think there is something about the X pipe that needs to be address ,there is a couple of different types of them.

-Parallel inlet and outlet

https://www.burnsstainless.com/images/technology/X-pipe_wb.gif

-Splayed inlet and outlet

https://www.burnsstainless.com/images/technology/Xpipe-splayed1wb.gif

-Splayed inlet - parallel outlet

https://www.burnsstainless.com/images/technology/X-pipe-splayed.gif

I was wondering what its the best suited to this car? Im doing my homework , But I guess there are some people on the forum you can give me a hand and explain in detail the pro and cons about them.

Regarding to the muffler basically a strait thought.
Has anyone try megaphones type? In my N/A days on the sr20de motor using this type of “muffler” got very nice improvements even re-routed back with a cat-back…( all the people was telling me it will not work etc but it did) I know its pretty tricky to get the perfect Megaphone size etc , Im just asking this questions I KNOW that there is already a formula that its works flawless ,FI cat-back got everything ok.

the NA exhaust is much more of a science then on the turbo car.

your doing good going with the X over h or thinking about not connecting the streams. Each X offers different results.

Parrallel is good for driving and low end tq
the splayed or quick isn’t as good down low but pulls good up top.

Guys

I was taking to the TÜV guy ( good friend) and he told me that performance mufflers are to to be prohibited now( over 78 decibels ) , well I was wondering if any of you have modified the stock mufflers? I have done this on another car with good results ( pass inspection ), maybe someone has some pics ?

B6 S4 Muffler inside.

http://farm3.static.flickr.com/2775/4156513709_f265b8f934_o.jpg

For example here its a EVO X muffler inside

http://www.worksevo.com/store/images/MufflerPath_EVOXa.jpg

Another example BMW
Stock

http://i995.photobucket.com/albums/af76/Roundel3/Shop%20Night%2009%20and%20Misc%20Work/IMG_9362.jpg

Mod

http://i995.photobucket.com/albums/af76/Roundel3/Shop%20Night%2009%20and%20Misc%20Work/IMG_9368.jpg

Regards.