Metal Rattle Sound
 

Hey all, ive been dealing with a metal sounding rattle for almost 2 years now...

The sound only comes on while im moving (under load) and at around 4k RPM. I have checked all exhaust components, and have been under my car with a fine tooth comb... its driving me mad, i even removed every piece of heat shield under the car, but it still happens.

I cannot reproduce the noise at a stand still, and sometimes the noise will go away for a while. Im running out of ideas... I have even removed the undertray/skid plate.

The sound seems like its coming from mid car, but I can't really tell while driving.

Ideas???

My old g35 used to make the same exact sound, usually when punching it. It sounded like clutch chatter to me, my 370 actually makes the same sound but not as loud. Look up clutch chatter while accelerating on google, a few forums pop up with similar noise complaints.

Might sound stupid, but have you ruled out the metal components of the jack sitting in the rear of the car in that hard polystyrene? I put one piece back wrong, and it rattled against another until I moved it (actually wrapped it in a small cloth too). I realize it should be pretty easy to determine whether your noise is coming from inside or outside the car, but just thought I'd throw it out there.

I've checked that, and I currently have no jack or tools in the car. The sound is most definately coming from under the car. I can hear the reflection of the sound when I'm next to something like a guard rail a lot louder.

Also it's not just under acceleration, if I hold at the rpm that makes it rattle it will keep on rattling forever. I wish what ever it was would just break already at least I would know what it was. It takes the enjoyment out of driving the car honestly

That's strange, could you possibly record a short video of the noise?

I will get one on my way home from work with my phone

I've always thought it could be something to do with the flywheel though... It sounds just like when you disengage the clutch at a stop, only really f ING loud and only at right before 4k rpm under load

check the tack weld CLOSELY on the flanges on the FI x pipe, chased that rattle for 2 weeks....right around 3500 rpm for me. Wiz that shiz right off.

check if the exhaust is rattling on the mid support, mine was it looked like it cleared, no problem, but it didn't while driving at some rpm's. Just give it a good shake while under the car.

It might be ur sub-frame bushings, i live in NYC and the roads are like those at the 3rd world country, my bushings are gone. Currently waiting for my replacements in the mail.

a video would definitely help. what mods do you have? could it be an intake pipe rattling?

http://i904.photobucket.com/albums/a...910_185354.jpg

That's the best video I can get right now. Doesn't do the rattle justice.

I will check the above suggestions. Where are the subframe bushings? Is there an easy way to tell if they are gone?

Don't think it's the intake pipes, I shoved some padding in there to test it out. Mods are momentum headers, z1 test pipes and fi nonres exhaust.

I realize the video I posted sounds like air blowing, but in person is definately sounds metal on metal. It's not the normal hiss or anything like that. You can hear it twice in the video, once inside the car, and once when I stick my phone out the window

i watched it on my iphone and i cant hear anything over the wind noise. apologies i cannot be of much help at this point.

have you put the car on a hoist and had an assistant listen while you rev/drive it with the wheels freespinning?

Do you also get it just under 2k?

I have the same issue and think it's from the exhaust hitting a support brace at those resonant frequencies. I haven't had the time or the tools to check though, but it's been going on for over a year now. I've learned to live with it, but it sure gets annoying sometimes.