So I know that an X-Pipe will "balance out" the flow and the sound, add some backpressure (good for low end torque), and will probably reduce droning to a degree, but I've only seen it installed in cases where the resonators have been removed. I have also heard that the X-Pipe can change the "character" of the sound. I think Joe (vegastrashed) mentioned that he didn't like the unbalanced muscle car sound of his AMG E63, but installing an X-Pipe changed the "character" of the sound from a muscle car sound to a more balanced sound like his 545 with the RD Sport exhaust.

I have the Remus quads (for the I6's) installed on my 545 and I really do like the sound a lot....it is deep yet civilized, yet I do have a little bit of droning....which I have and can easily live with. However, I was just wondering how an X-Pipe might affect the sound character and/or the slight droning on my car. For those that don't know, the Remus quad is a single muffler on the left side with a pipe coming out of it and running to the right side. Therefore, it only replaces the OEM muffler while leaving all three resonators in place. If I were to have an X-Pipe installed in between the front tube resonators and the center box resonator what would your guess be as to how it may affect the sound/droning/low end torque? Would the X-Pipe have the same affect as it does on cars with all resonators removed and replaced by the X-Pipe or would it be less noticeable?

 

I think you'd be the first person to try that type of setup Rody. Only one way to find out!

 

X-pipe, like h-pipe, are used in very high performance engine to balance the exhaust pressure from both headers to gain additional hp. Some pros have found that it helps with sound level reduction of 1 to 2 decibels. Do a search on the web by typing in "x-pipe design vs. h-pipe" and you'll sell that some have backed the x-pipe with dyno test.

In your situation, your center resonator box "y" into a 3" tubing/pipe. In a way, it balances the exhaust gas pressure similar to an x-pipe (think of fluid dynamics 101) on a simplistic level. So, adding an x-pipe to yor current Remus configuration probably won't do much except change the volume of pressurized gas. The performance of an x-pipe on a 545i may produce 1 or 2 added HP. As for the sound affects, if will probably help with 1 to 2 decibels less droning since x-pipe are known for raspy while h-pipe is for low muscle car. Nascar uses x-pipes. Like I told VT in the thread below, muscle car sound usually comes from chambered mufflers (like flowmaster), which I think his AMG mufflers are chambered with few packings. In any case, if you can hear that difference and the cost is right, then it's money well spent.

Look at my undercarriage video.

http://forums.e60.net/index.php?showtopic=50282&st=0

The reason I used the x-pipe between my 2 resonators right before the center box resonator is because I have 2 separate exhaust path - 1 for each header. The x-pipe crosses the 2 paths. I could probably use an h-pipe too, but x-pipe is the latest discovery and I didn't want more "low frequencies" than what I already am suffering from.

By the way, where does your Remus drone level fall based on my stuffed muffler and straight-through videos?

 

Rody,
Please post a pic of the undercarriage of your 545i. Visuals help a lot!

 

Thanks for your reply. As you mentioned the center box resonator does act as a Y-Pipe, which is the main reason for my asking this question. Basically what affect would an X-Pipe followed by a Y-Pipe have? I may try it out just for the heck of it, but I'm a little worried about your comment that X-pipes are known for raspy sounds. I don't like raspy/tinny sounds like the Eisenmann Race exhaust for the 545......but I guess Joe's RD Sport on his 545 had an X-Pipe too but it did not sound raspy.

To be honest I can't hear much on my laptop speakers, but I'll try to remember to listen to your clips on my work computer tomorrow (which has much better speakers) and I'll post my opinion on where the Remus droning fits compared to your clips.

 

Joe.......I don't have a pic of the undercarriage, but next time it's on a lift I'll take a pic.

The current setup is stock all the way to the muffler, which means headers+cats, tube resonators and box resonator. After that it's just the Remus muffler on the left side and a pipe that runs from the rear of the muffler to the right tips.

 

The x-pipes won't give you that much of a raspy sound since your Remus muffler (straight through assuming) are producing the "rumble" sound. It's like a mix drink. Like I said, x-pipe will slightly affect your sound note if you have sensitive hears like me to hear it.

Personally, I'd spent the $150 installed on something else unless the slight drone in the Remus is getting annoying.

 

I finally listened to your clips on my work computer. I would have to say that the Remus quad's droning is less than both the straight-through exhaust and the stuffed muffler. While the droning is not a huge deal lower than the stuffed muffler, it's still noticeably lower. Of coarse, I can't be a 100% accurate in my estimation since it does depend (to a degree) on the volume setting of the speakers when I listen to the clips.

It's interesting that when I listened to your clips on the tiny speakers of my laptop there was no droning at all, but on my work computer with the sub woofer I could both hear the droning and feel the vibrations of the droning as if I were sitting in the car. This just confirms that droning is a low frequency issue and the laptop's speakers are not able to produce low frequencies.

 

I agree with this as well..

 

Thanks for your opinions guys