Edd20022 Posted June 2, 2014 Share Posted June 2, 2014 So I have had my Z for a a couple of months now and since I have had it, I have heard a rattle coming from the underside on the car ( sounds like its directly under the drivers seat) when the car is revved to approx 2/2.5k RPMs . It sounds like a tinny vibration and it makes my Nismo exhaust sound like a bag of dicks! And it's really embarrassing as it sounds like something is about to fall off. So some info on my exhaust, Nismo S tune cat back, resonated De cats ( make unknown) I also have a slight blow also coming from under the car too which is getting sorted...however I don't think is the cause of the rattle. Also, the noise is very very faint on a cold start...once it's been driven for a while the rattle is unbearable. Now I appreciate this is a post which has come up before from others users....pretty sure I have read them all, but what I haven't seen is anyone that has a definitive solution, has anyone had this issue and managed to get it sorted? I have been told it could be the de cats/ heat shield/ baffles/ something else touching the system. I have read lots of scare stories of de cat/ hi flow cats buggering Nismo exhausts by blowing out the baffles, and the last thing I want to do is take it off. So before I take it to the garage to pay some idiot who just learned to walk upright that morning to waste a days worth of labour just to shrug his shoulders and mumble "I dunno" like the greasy ape he is... Does anyone have an idea of what the issue is, or even better....a fix!? Cheers Quote Link to comment Share on other sites More sharing options...
HAMLNJ Posted June 2, 2014 Share Posted June 2, 2014 Have the same problem, you will notice there isn't a brace bar supporting the decats. It's the flexi's on the y pipe causes the rattle. The decats need more support. You can use the same brace from the stock cats with a couple of welds and two bits of metal to correct it. Hope this helps. 1 Quote Link to comment Share on other sites More sharing options...
Edd20022 Posted June 2, 2014 Author Share Posted June 2, 2014 Thanks for the reply mate. Did this solve the problem for you? Has the rattle gone? Please say it did.... Quote Link to comment Share on other sites More sharing options...
HAMLNJ Posted June 2, 2014 Share Posted June 2, 2014 Yes, I'd suggest to look underneath or google OEM exhaust set up and then compare to yours. You will notice a large brace bar missing. The OEM bars for the cats don't match for (I suspect ebay decats) Good welder, two bolts and some small plates it will fix it. It drove me nutty and driving down a high street it sounded like my exhaust was rattling like a rattle snake. Quote Link to comment Share on other sites More sharing options...
HAMLNJ Posted June 2, 2014 Share Posted June 2, 2014 I have some photos for you. Give me a sec Quote Link to comment Share on other sites More sharing options...
HAMLNJ Posted June 2, 2014 Share Posted June 2, 2014 Can't upload pics, though they are only 130kb it says there too big? Admin? Help! Quote Link to comment Share on other sites More sharing options...
Paddy78 Posted June 2, 2014 Share Posted June 2, 2014 Photobucket? Google+? Quote Link to comment Share on other sites More sharing options...
samsniss350z Posted June 3, 2014 Share Posted June 3, 2014 I had a rattle although this was on an OEM exhaust so don't think it will apply to a Nismo exhaust but eventually found out than one of the chrome tips had come loose. Bloody thing was making a hell of a row but a few pinches with some molegrips cured it. Quote Link to comment Share on other sites More sharing options...
RobPhoboS Posted June 3, 2014 Share Posted June 3, 2014 (edited) http://www.350z-uk.c...es/page__st__20 Same kind of problem I had, I didn't spot it initially.. kwikfit did (for free) Worth checking. Edited June 3, 2014 by RobPhoboS Quote Link to comment Share on other sites More sharing options...
CrustyCrab Posted June 3, 2014 Share Posted June 3, 2014 I had a tizzing nose coming from mine and it turned out to be the heat shield above the back box had dropped down as it had corroded through. Just dropped the back box and put some washers on it. Solved the problem but to bloody ages to find it was that. Quote Link to comment Share on other sites More sharing options...
Edd20022 Posted June 3, 2014 Author Share Posted June 3, 2014 At first I thought it was the back box, but it's clearly coming from the front. The suggestion that the cat support brace is missing is probably my best avenue to investigate, and I have managed to pick up a brace for £20. I will update if this is a fix for me or not as I am sure other people will have this problem. Quote Link to comment Share on other sites More sharing options...
BulletMagnet Posted June 3, 2014 Share Posted June 3, 2014 Also check for loose y-pipe heat shield Quote Link to comment Share on other sites More sharing options...
Jo-Jo Posted July 15, 2014 Share Posted July 15, 2014 I'm exactly the same, only had my 370z Nismo a few weeks and it's so embarrassing. It's been in the garage now twice and they can't figure out what it is. I'm losing the will to live... What should I tell them it is so they can fix it please? Quote Link to comment Share on other sites More sharing options...
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