Howdy folks,

I have a Nismo cat back exhaust on my 2004 350z, this exhaust has been on the car 2 years, no problems. I added Berk HFC 6 months ago and have now encoutered a problem....

The exhaust sounds awesome, i do get the rasp at 3-4k revs as per normal with these HFC's but now the exhaust has developed a "tinny" rasp at only 2.5k revs. It only makes the noise at this rpm level and only when under load, ie. not when the revving the car in neutral.

My mechanic took the whole exhaust off this weekend past and tightened everything, all the heat shields, bolts, etc and put it back together and the noise is still there at 2.5k revs, it sounds like it comes from the back box and not from the cats, definitely sounds like it's coming from the back of the car.

It's really annoying and ruins the pleasure of driving the car when you travel trough the 2.5k mark it makes this stupid "tinny" rasp noise

I'm a member of the UK 350z owners club and they're all miffed what it could be on that site and now my mechanic is miffed about the noise, next stop Nissan i reckon but i figured hopefully the Americans could enlighten this Irish boy first !! Also i don't think it's baffles that are loose in the backbox making the noise as the noise doesn't happen when the car is cold, only begins when the car starts to warm up !!

So i know there are members on this site who run the Nismo + Berk set up so i was hopping someone had come across this before.

Thank you for any help,

Pete.

 

^Its normal.. The HFC's are causing the tiny rasp.. A simple fix is to keep it above 2.5k rpm

 

Is it a rasp or is it a vibration noise? I had an issue with my dual exhaust barely touching my right suspension in the rear after I took off the cats. I think since test pipes/HFCs weigh a good amount less than the stock cats the exhaust doesnt hang as low as it previously did.

I only kinda fixed it, I compressed the rubber hanger that holds the exhaust in the back so that it is now more elongated and provides enough clearance.

 

I have the same setup as you and I dont encounter any rasp at all unless the exhaust is cold. Check your HFCs to make sure the core is intact. Ive heard some stories about Berk HFCs cores breaking apart or something like that. Good luck!

 

If it is rasp and not vibration noise, you could look into getting Motordyne's XYZ pipe with the resonator.

 

+1 on the xyz pipe

 

If the cores were breaking up, it would sound like marbles in a can...
His "tinny" sound is more then likely attributed to the HFC's. I had the exact same sound on my setup with Berk HFC's.

 

But wouldn't the rasp at 2.5k have been there since they were fitted 6 months ago ? Only started a month ago ?

I read nothing but good things about the Berk HFC online and didn't hear any stories of them breaking up or causing the Nismo zorst to crack so that's why I chose them over every other brand in the end.

I'd be gutted if they were causing the problem but to be honest i think i'll take them off in the coming weeks and see does the 2.5k "tinny" noise go away.

Thanks,

Pete.

 

Dam,
Didn't pay attention and just noticed that you have the Nismo exhaust...

I would switch out ypipes, asap...

My berks cracked when I had it mated with my nismo exhaust.. the dam ypipe does not "flex" enough...
I now wonder if you are experiencing some sort of initial failure..

 

Some sort of initial cat failure or Nismo back box failure ?? I presume all this would be internal failure as when the Zorst was removed at the weekend there was nothing obvious to the mechanic on the outside...

 

If the glass packing in the midpipe resonator is blowing out, that could cause an increase in rasp.

 

Does anyone think that removin the Berks solve the situation or is it too late ??

Thanks,

Pete.

 

The Berks won't cause anything that isn't reversible upon removal. Such as rasp.

If however the midpipe resonator has lost glass packing, it is not reversible and it doesn't have anything to do with the Berks.

 

bump!



is there glass packing in the stock mufflers?

 

Yes.

 

so my muffler may indeed be bad!

Thank you!