[Lancelot]

Hi all

So I went to the exhaust shop a couple of months ago for a X Pipe, but they advised against it, saying that wasn't optimal for the twin turbo V8

I got the straight pipe done, and I have to say that was a festival of burbles and pops and crackles, so I was happy, except under heavy load/3-4krpm where the exhaust was loud and not particularly enjoyable, really like a 4 cyl engines, which it is a pair of really...

So went back to get a X pipe done, and now it feels like it's back to stock.
X pipe is well done and look much like what I've seen around here.

No burbles/crackles, all gone, I must say I'm somewhat confused since many here have great things to say about X-pipe (and many have great things to say about straight pipes either), it's just the difference is so huge.

I'm leaning towards putting back a single resonator instead of the X now, like the M850i has.

What do you guys think?

Thanks

[Antec800]

Whoever said x pipe is not recommend for a turbo v8 is a idiot, keep the x pipe you don’t want your car to sound like shit from having no crossover, also the pops and burbles don’t get affected much with a x pipe, only cats, resonators and mufflers affect how loud the burbles are

[Lancelot]

Originally Posted by Antec800

Whoever said x pipe is not recommend for a turbo v8 is a idiot, keep the x pipe you don’t want your car to sound like shit from having no crossover, also the pops and burbles don’t get affected much with a x pipe, only cats, resonators and mufflers affect how loud the burbles are

Yeah too bad i can’t keep the louder burbles of the straight pipes without the obnoxious sound under full load

How is the need for a crossover explained? Physically i mean, how does that affect the air flow ?

[Boosted_8]

https://www.motortrend.com/how-to/15...for-your-ride/

[23109VC]

So I started another thread but I did the same thing Lancelot did. I asked for a resonator delete..and dind’t tell teh shop straight or X pipe. They just did two straight through pipes.

So not i get very cool sound but just like Lancelot said - around 3k rpm under full load I get what sounds like 4 banger rasp for about 500-1000 rpm. It sounds shitty…. It will even do it in comfort mode…so you don’t get “quiet” in comfort if you hit it.. you get a bit farting obnoxious sound as it revs past 3k.

I am going to go back and have it modified to an X pipe. Doe sit matter how far up / down stream the X section is? Does it make a. Big different HOW Much of a cross over it is -= I’ve seen some people with what’s looks o like there is a smaller opening or a larger welded opening… or is the real issue i just need SOME crossover of the exhasut to take that rasp away?

Shoudl not be too $$ to have a shop fab it - as I already have the resonators out and all the piping is in..they woudl just have to fab a small X pipe sections nd weld that into the existing system….

Thoughts?

[weinerbarn]

Most of the research I did previously when I was going to fabricate my own was that about a 1/3 of the pipe diameter should be removed on each side and then joined together. So on 3 inch pipe sections as an example, you should still be left with about 4 inches of "girth" in the middle. It won't really matter too much how far up or downstream it is, roughly where the resonator was is fine. This isn't an F1 or Nascar where you're dialing in the powerband. If your exhaust shop is not familiar with building x-pipes, you might also just buy a universal one that's the correct pipe diameter and have them weld it in versus a chop job.

[Bsm550]

I got the dinan midsection with x pipe and its awesome rowdy when i want and quiet when i want

[Boosted_8]

I still had a fair bit of drama with an X. This was once the secondary cats were removed mostly. H pipe is the half way house I guess. This is effectively what's inside the centre suitcase if you were to cut it open.