i am new to the forums however I would like to share what I am currently modifying on my 2004 XJR. As I look for ways to increase performance without losing reliability I decided on a new exhaust system.

My car currently has a Magnaflow X-Pipe and Magnaflow Mufflers installed. All the original piping from the cats have been increased to 2.5 inch. Removing the resonators has made the car a lot louder and I might go on to reinstall them at a later time in the future while keeping the mufflers and reducing the overall sound.

 

My 2006 XJR had the resonators removed and Magnaflo mufflers installed at some point in its history. No X-pipe was installed. What advantage is obtained from the X-Pipe?

 

From my understanding, the X-pipe is more efficient when the exhaust gases are released from the engine. For example, the exhaust flow of an X-pipe is almost always more beneficial than an H-Pipe; in an x-pipe the gases are forced to converge together in an equal way while speeding up the exhaust flow process out of the system.

 

When you tie the two banks together with either a X or H pipe, the exhaust pulses from the escaping gas from one bank is used to help, at least in theory, to assist scavenging the opposing side's exhaust gases. Depending on it's implementation it can certainly change the exhaust note out the dual exhaust pipes, but it can also benefit, in a properly designed system, low and midrange torque. If improperly designed, it can actually hinder performance. A chassis dyno is really needed to determine the effectiveness of any exhaust design, and manufacturers really do spend a lot of time in their initial system design.

 

Can we assume that the original resonators acted like an X-Pipe since both banks shared the same muffler case?