Exhaust midsection rattling......172 Cup

[Icarus83]

Having a lot of resonating noise from my exhaust, mainly between 2 and 4k in all gears. I have heard of the centre section going on Cups however everything from the cat back if fairly new. The cat itself looks corroded so my thoughts are its that that is the main offender. Do these break regulary, and is it an expensive replacement.

Is this a good opportunity to fit a de-cat, and how does a de-cat fair with MOTs?

The noise itself on my car sounds like the heat shield is loose under the passenger footwell, but on inspection everything is still bolted down.

Any ideas guys (and girls)?

 

[Icarus83]

Bump.

 

[DanS]

check your rear exhaust mount, it might need replacing.
When I got mine it had a horrible loud rattle at 4000 rpm and turned out to be a knackered exhaust mount which had dropped the exhaust!

 

[Icarus83]

My rear exhaust mount is perished, and had always made a small amount of knocking when cold......as soon as it was warm no noise! Maybe its really died and the exhaust is whipping about a little too much!

Any idea how much I'm looking at for a mount?

Cheers

 

[Jay Payne]

bout £20 for a mount iirc

 

[bobby_the_one]

check the gasket, had similar problem my gasket had gone and was pissing all over the place.

 

[Icarus83]

check the gasket, had similar problem my gasket had gone and was pissing all over the place.

Which gasket do you mean, the manifold? all other joints are overlap fits with jubilees.....?!

 

[maz172cup]

cups always rattle, mine did it from new, geta sports exshaut

 

[Icarus83]

cups always rattle, mine did it from new, geta sports exshaut

Lol

The exhaust is as far as i know an aftermarket job, but not a shiny stick out the bumper kind, sits nicely inside the bumper, and the rattle I have now is a BAD BAD BAD noise compared to the noise I usually have! :S

 

[Icarus83]

I think my exhaust system is a K-tec stealth system. the one on their website looks identical to mine.....and looks fairly new.....was on the car when I bought it so I'm not sure.....

Had a look at the cat on my car too, its very rusty, so I think it may be the cause of the noise if its knackered. Any ieas how much am I looking at for a new one, or just to get a second hand one? Also weighing up the idea of (as the prices are similar) going for a sports cat instead.......

Think a trip to kwik fit or something may be in order.....

 

[Jambo182]

check the spring bolt on your cat, i put a de-cat on my 182 and had the same problem with rattlin which i also thought was my heatshield but turned out to be the springbolt also check the baffles in the centrebox

 

[NIN-172]

Does it only do it when it gets warm?
There were constant posts on this issue when I got my 172. Was known as the 4k rattle.
Mine did it when you were coming off the throttle & the revs dropped down. At 4000rpm it would vibrate inside the car.
I had the middle section took out & a straight piece put in place.

 

[jooliona]

might have popped a weld. it's easily done depending on who welded it!