Update on the X-pipe noise
 

Took the X5 in to two additional exhaust shops one of which did custom installs to ask about the raspy sound that sounded like marbles in the pipes at higher RPM's. Seems like it was installed correctly with no leaks and the sound especially when cold is an echo which is muted by the factory resonator. I can't explain why others with the V8 don't hear this but open your door and rev the engine while cold and you can't mistake the sound.

It almost sounds like bad catalytic converters but mine were inspected and are fine with only 40K on them. Anyway...I'm pretty disappointed with the sound especially now that I'm stuck with the rattle. I guess I should have trusted the BMW engineers who decided the resonator was needed.

Michael

Sorry to hear about this. Why are you revving a cold engine? That will cause a lot more problems than a little rattle.

Does the rattle go away when warm? DanDE mentioned a cold rattle when he removed his resonator but he did not install a crossover pipe.

Is the rattle coming from beneath the car or is the sound coming out of the tailpipes?

Sounds like you guys are doing the opposite of what the E46 M3 guys are doing. The E46 M3 has a famous raspiness in their exhaust which has been toned down for 2004+ M3, but it is still there. Currently, the E46 M3 has one resonator in the left pipe, but the right pipe has NO resonator. Rogue Engineering and other companies have produced a "rasp-reduction" pipe by replacing the BMW OEM M3 resonator with a smaller resonator on both the left and right pipe. The exhaust sound is a little quieter, but the rasp is pretty much gone.

The X5 4.4/4.6/4.8 guys want more sound so they get rid the resonators, but there is that risk. I wonder if the X-pipe has a different effect on the non-valvetronic V8 vs. the valvetronic V8?:confused:

http://www.rebmw.com/Merchant2/graph...sp_pipe_sm.jpg

Yeah I hear you there...Not really redlining the engine. Just reving it up past 3000K and you hear the sound loud and clear from under the car at about the X-Pipe location. It does not go away but the sound is reduced when it warms up somewhat.

It is really annoying to the point I think about replacing the factory resonator. I wish I'd done more research before doing this mod because now I've chopped up the factory exhaust.

Well if you hate the sound it would be a piece of cake to put back to stock. Just a matter of welding the resonator back in place. I don't know what straight pipe (no xpipe, no resonator) would sound like on a '01 4.4 but I assume you would still have the noise you are talking about. The Xpipe isn't creating any sound of its own so it must be the unmasking of existing bad sound that you are hearing.
It was a relatively cheap mod so if you have to put it back it won't be too expensive. You can sell the Xpipe in the For Sale forum. Bet it would sound righteous with a good set of mufflers on it though.

Good luck and let us know what you end up doing.

i got my stock resonator removed on my 4.8 after doing that, my X5 sounded like a Mustang it had the beefiest but most rattleist sound ever, sounded good but the rattle got to me. So i decided to purchase an X pipe and after doing that, and installing it, the rasp almost basically dissapeared, i still have it a little, but it sounds perfect now i think.

So it depends to your personal preference and how u think ur X5 should sound..

You're right there. Good thing I drove back to the shop to get the factory resonator after my first experience taking the onramp with my window open. It was disheartening to discover I had marbles banging around in my SS pipes.

Total cost was about $160 plus another $80 to go back to the stock setup.

Michael

From reading other posts here on the X-Pipe the 4.6 and 4.8 is a bit louder which might cover the rattle enough to live with the improved sound. I'm sorry to say the same is not true with the 4.4L.

You can always to the glass packs from the exhaust mod section of this site.

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Sorry this mod didn't work to your satisfaction. The cold rattle has been documented in some previous X5 x-pipe and straight pipe replacements of the resonators. It's also been noted by M3 and M5 owners with similar installs. I may not be hearing it because my X5 sits in a warm garage overnight. The rasp/rattle sound doesn't go away after the X5 is warmed up?