Scraping noise from exhaust?

[bcfc_mitch]

I've got a ridiculously loud exhaust on my car, a straight through de-cat, sounds great when you apply throttle but as you take your foot off the throttle and the revs come down it makes a scraping sound, one of my mates has the same problem with a factory exhaust and aftermarket backbox!

There both slow little 1.2 8v, just wondered if there was any known fault that I can look for when i get it on the ramp at the weekend?

 

[edde]

back box is probably cathcing/ engine mounts are worn

 

[Clarkie172]

is it high pitched? My 172s heat shield was touching something up near the down pipe/cat

 

[bcfc_mitch]

Yeah its a high pitched scraping sound, thats the best description I can give you really! I'll check all the heat shields and mounts, touch wood it'll be something nice and cheap! Cheers for the help!

 

[Papalaz]

My mate on his Type R has just started getting this exact problem after fitting a decat, definately didnt have it before and it only happens when he lifts off the throttle

Let me know if you discover the problem, we have checked his and there is good clearance all round, nothing catches etc

Any chance its air flow through the de cat pipe itself causing the funny noise when the power is taken off?

Thanks

 

[bcfc_mitch]

See now thats getting me worried! Its a pretty horrible noise and if I can't find a problem I'll probably replace the exhaust system, which I was planning to do anyway, but it was bottom of the list!

I'll let you know what I find!

 

[MarcoB]

Is the spoiler on your car in the pic a genuine renault part?

 

[lemonnobby]

Bristol? where abouts do you come from

 

[bcfc_mitch]

No its an aftermarket spoiler!
From like Hanham/Longwell green, familiar with?

 

[lemonnobby]

yea i live in kingwood there a few of us about from kingswood staple hill

 

[bcfc_mitch]

Well my cars off the road at the moment, tax run out
But if a few of you are meeting up then give me a shout you can pick I up!