Buzzing when letting off at high rpm

[ash_89]

Have a loud buzzing noise coming from what sounds like the exhaust on my 172 CUP.
First thought was checking all the heatshields ,these are all solid no rattles from what I can tell. Next thing to check is the baffles on the exhaust.

Has anyone else had this? Its only on de-acceleration from high rpm, I'm not a fan of the Honda style bzzzzzz.

 

[the_baron_von_richthofen]

Is the backbox or the pipe that goes over the rear axle catching on the body work, or close enough to catch it when the engine moves?

 

[ash_89]

Is the backbox or the pipe that goes over the rear axle catching on the body work, or close enough to catch it when the engine moves?

Going to have a good look over the weekend mate, hopefully its something simple.

 

[chazza114]

When you're having a poke around the car, try to take a look at your centre exhaust hanger, as well as the rear. The OEM centre hangers are known to be pretty weak and perish quickly. My centre hanger had collapsed, causing the exhaust to rest against the rear beam and buzz like crazy on decel from high revs.

BTT Motorsport sell a polybushed centre mount which I've fitted to my car, it solved the issue easily: https://bttmotorsport.co.uk/collect...172-182-btt-polyurethane-centre-exhaust-mount

 

[Mr Underhill]

When you're having a poke around the car, try to take a look at your centre exhaust hanger, as well as the rear. The OEM centre hangers are known to be pretty weak and perish quickly. My centre hanger had collapsed, causing the exhaust to rest against the rear beam and buzz like crazy on decel from high revs.

This!

My exhaust used to resonate badly under heavy acceleration. Couldn't get to the bottom of it so just lived with it.

Then I bought some new exhaust hanger brackets - the ones attached to the boot floor - and some mounts and low and behold it sorted it.

The hangers were so minging they were recording the sound and playing it back to me lol

 

[ash_89]

Cheers guys,

Just ordered one of the BTT Motorsport center hangers, mine currently has a Oem one fitted ( I know how shocking they are haha).