[OrangeVee]

Hi boys! I have a 2004 SpecV and have a lot of mods on it, including AEM CAI, HotShot 4th gen header and GReddy Evo 2 catback. The reason I mention those is because when I accelerate hard, I hear a metal vibration sound between 2000-3000 rpm and it's really starting to get on my nerves. It's like a heatshield rubbing sound or something... We checked for that but everything sounds ok. We checked for header leaks or exhaust leaks, and nothing is wrong. I also took out the useless bracket after the resonator that is sitting there doing nothing (for the exhaust line not to fall on your head I guess when you're changing it) and this still didn't solve the problem. Could it be my CAI rubbing on the body part where the CAI goes into the wing? Because there the CAI is tooching the metal... Any ideas? Has anyone experienced this? It's realy an ugly sound and I hope there's a way to fix this. The sound is pretty raspy and comes on and off between 2000-3000... It's like if it was following the movement of the body and tires (riiiing-riiiiiiiiiing-riiiiiiiiiiiiiiiing)... Please help!

 

[audio1der]

Try to isolate the CAI fro mthe fender hgole if possible. Line the edge of the hole with rubber or something similar.
If that's not it, check your exhaust hangers under then car, to make sure they're not resonating aginst the underside of the car.
Also tighten your e-brake if you can (http://www.b15sentra.net/forums/showthread.php?t=62228&highlight=e-brake+adjustment)

Hope this helps. I'm fighting a resonant gremlin, too. Have to get the gf to sit in the car & give it gas while I'm under it to inspect the hangers when I get home)
Godd luck!

 

[OrangeVee]

That's it? 53 views and only 1 reply? I can't believe no one else is experiencing wierd vibration sounds in that rpm range...

 

[OrangeVee]

How would you isolate the hole in the fender?

 

[Pro Spec V]

This has been discussed a couples times and the way to do is to take a plastic tube and cut it down the center to put it on the sheet of metal around the CAI with silicone in the plastic tube. As shown in this install:
http://www.nissanperformancemag.com/october02/aem_cai/

 

[soupbone]

look under the car at the heat shield that protects the fuel tank...and check all the heat shielding underneath the car...check it carefully...although you removed that bracket, you may still need to bend the heat shielding back slightly to separate the contact point of the exhaust and the metal...

 

[dualmax]

dude, is your virbration noise happen between 2-3 thousand rmp? if so you are not alone, I have the same virbration noise, sound like a chain rubbing on something, I don't have cai so it can't be that, I took it to nissan and they said that is normal, so I just live with it.

 

[lawngn0mex]

It's normal.... it's the natural vibrations from a 4cyl motor.. that's why we have balance shafts.. with them out you'd feel it moreso than hear it... good idea to check all heatshields and the CAI as well tho.

 

[OrangeVee]

Thanks for helping out boys. Yeah but before I had the header on, it never made that sound... That's the funny thing. Maybe the header amplified it?

 

[WishihadanissaN]

is your L brackett on the header attached? mine was making that noise as you described, it would also make my intake rattle alot hitting the whole it was going into. I finally bought a screw and nut that would fit since the stock screw doesn't line up perfectly to the block, and attached the L bracket from the header to the block and problem solved. car feels much better and it doesn't feel bad anymore when i have the AC on. It would vibrate alot before this. you can put some some electrical tape on the metal to keep it from clanking for the intake. but if your L bracket on the header is not attached to the block, i would do that first.

 

[OrangeVee]

Pardon my ignorance, but what is that L bracket on the header you're talking about? Where exactly is it? Any pictures? I have absolutely no clue...

 

[WishihadanissaN]

on the bottom of the header, see the little brackett on the right of it, looks like an L. the stock manifold has the same thing and bolts directly to the block. the same thing should be done, when installing the hotshot header.

 

[OrangeVee]

When you mean bottom of the header, to you mean that little piece that's sticking out on the right, where the downpipe would bolt on???

 

[OrangeVee]

It might sound stupid, but could you circle the L bracket on the picture?

 

[WishihadanissaN]

yeah the 2 holes there are for the downpipe and than the little brackett there has a hole in it. you put the screw through there and it attaches to the bracket on the block.

 

[LASE-R]

Its the small bolt that holds the bottom of the header (the exhaust flange) to the engine block with a small bracket. You should have seen this when you installed the header. I have the same problem as you. I still have a vibration using this bracket but not as much. I have'nt tried to locate this vibration yet but it bothers me too.

 

[WishihadanissaN]

here you go.

 

[OrangeVee]

Does the 4th generation HS header come with that L-bracket as well?

 

[WishihadanissaN]

you can see it if you open up your hood and look down at the header. it's right at the bottom. and yes every gen since the 2nd has had that bracket.

 

[sentra02boy]

I know my intake is rubbing in that hole and I here it rattle at times but its only when i hit a bump or something it sounds like a metal scratching on metal though but my CAI doesn't have a mount so it just sits there and slides up and down when I hit holes so if yours has a mount and its touching still it is very possible that it is only touching lightly and under the vibration from the motor it causes the rattle I would try to stick a towel or something around the hole between the hole and intake maybe duck tape it so if your intake starts bouncing it doesn't fall out see if its any quieter make it a little thick though so it doesn't rattle thruogh the towel