Rattling noise down the rev range

[FUG]

Hi guys noticing a rattling noise when coming down the revs , not sure if it's coming from under the car or wheels , typically rev along in 2nd or 3rd up to 4k and let the revs come back down and can hear it for a few seconds , doesn't seem to make the noise when stationary though?? Any ideas ??

[ianphampton]

Is yours an aftermarket or stock exhaust?

 

I have a Crapspeed K2 zorst and mine rattles a bit when cold, disappears when warmed up - perhaps yours is loose baffle or something?

[FUG]

I have a milltek system , standard cats ?

 

Is it fairly straight forward to check / change baffles ? Expensive ?

 

The noise has only appeared recently and makes the noise when cold or hot

[Hooch]

Exhaust heat shields?

 

I have heard that stones can easily get caught in one of the mid heat shields above the exhaust, could be that?

[deankenny]

MY recently sold 350z rattle on the down revs also, only did it when after i fitted a Stillen Y-Pipe, which does not have the flexi

[FUG]

The garage I spoke to seemed to think it may be oil starvation?? The dip stick is such a shite design IMO it wasnt until the 5th attempt smear free where it may potentially be low , had a full oil change not so long ago though... :/

[deankenny]

The garage I spoke to seemed to think it may be oil starvation?? The dip stick is such a shite design IMO it wasnt until the 5th attempt smear free where it may potentially be low , had a full oil change not so long ago though... :/

 

Not heard that one before

[peteman35]

Cat heat shields mine did it ripped one off it stopped. Now the other has started so that one will be beaten to death as well.

 

Simple job just takes patience

[WINKJ]

Sorry for the thread revival, however I have recently fitted a stillen cat back exhaust and I now have a terrible rattle/bang when the exhaust it warmed up. Not got a clue what it is and it's been driving me nuts all day. Just can't seem to spot it and sort it!!!

 

A lot of the U.S. forums suggest that the exhaust is hitting the Crossbrace but I seem to have enough clearance...

[Lexx]

It may look like enough clearance, but if you give a good yank down on the exhaust it could hit it.

I had the same issue on the RX8 with an aftermarket exhaust.

 

I just spaced the cross brace with a few washers. Solved it.

[WINKJ]

It may look like enough clearance, but if you give a good yank down on the exhaust it could hit it.

I had the same issue on the RX8 with an aftermarket exhaust.

 

I just spaced the cross brace with a few washers. Solved it.

 

Thanks lexx, does the fact that it only seems to be when its hot make a difference?

[comrade]

Lift the car up and bang on the exhaust with something soft to make it vibrate, you will tell straight away where the rattle is coming from. Mine was due to the cat heatshields being so rusted that they were pretty much not there anymore.

[WINKJ]

Also been pulling it around etc... No sounds or movement at all

[WINKJ]

Lift the car up and bang on the exhaust with something soft to make it vibrate, you will tell straight away where the rattle is coming from. Mine was due to the cat heatshields being so rusted that they were pretty much not there anymore.

 

The car is pretty much brand new!!! Will give it a go

 

Just tried... No luck. It's more of a clunk than a rattle too. Also sounds like a scraping clunk when taking a hard left turn!! Very odd. The When th car is hot it does it even going slow in a straight line on any small bump

Edited September 28, 2014 by WINKJ

[GIXXERUK]

The only movement the exhaust shouldl get is from the engine mounts

 

Have you checked all the rubber hangers are still in place

 

Esp. The two hangers that stick out after the mid pipe silencers

 

 

 

Edited September 28, 2014 by GIXXERUK

[comrade]

Lift the car up and bang on the exhaust with something soft to make it vibrate, you will tell straight away where the rattle is coming from. Mine was due to the cat heatshields being so rusted that they were pretty much not there anymore.

 

The car is pretty much brand new!!! Will give it a go

 

Just tried... No luck. It's more of a clunk than a rattle too. Also sounds like a scraping clunk when taking a hard left turn!! Very odd. The When th car is hot it does it even going slow in a straight line on any small bump

 

Oh, i didn't realise that yours is a 370. Even the newest 350s will have rust underneath by now Are you sure that it is the exhaust that it is clunking? Did the noise appear straight away after fitting it? Did you change anything else on the car at the same time?

[WINKJ]

Lift the car up and bang on the exhaust with something soft to make it vibrate, you will tell straight away where the rattle is coming from. Mine was due to the cat heatshields being so rusted that they were pretty much not there anymore.

 

The car is pretty much brand new!!! Will give it a go

 

Just tried... No luck. It's more of a clunk than a rattle too. Also sounds like a scraping clunk when taking a hard left turn!! Very odd. The When th car is hot it does it even going slow in a straight line on any small bump

 

Oh, i didn't realise that yours is a 370. Even the newest 350s will have rust underneath by now Are you sure that it is the exhaust that it is clunking? Did the noise appear straight away after fitting it? Did you change anything else on the car at the same time?

 

Nope just the exhaust. I think I may know what the problem is.

 

When you fit the stillen you have to remove a bracket which is specific to the nismo exhaust to make it line up. As a result the nut sits higher than it would normally. Which is rubbing against the nismo ARB. (I think it is called a that). Normally it would sit lower due to the bracket. Which may also explain the noise when turning left!!! So the solutin would be to fit a nut that isn't as long.

 

Popping back to the garage to see if they can sort it.. Hopefully won't charge me!!!!