boomy exhaust

AndyEll · 16th August 2015, 22:07

So from time to time I get a boomy noise from the exhaust. Sounds like its hitting off the bottom of the car somewhere but when I jacked it up and gave it a good shake it didnt seem to be hitting anything. It sounds like its resonating at certain rpm. Also the back box outer case is rusted through,not a huge amount,just the size of a coke can missing below the tailpipes. Any input welcome.

KWIL · 17th August 2015, 09:03

Back boxes are also called resonators and yours is because its characteristics have been changed by the "rust holes". If only the outer case has gone this should not cause much of a problem, look around the input pipe area as well. Changing it for a non MGR one will/may also give you strange noises!

ProfDave · 17th August 2015, 09:14

If when you are driving its hitting the car worth checking your lower engine mount condition; agree with the other comments; I went for stainless replacement on two cars which car a nice note but are louder. The quietest by far is the saloon which is still on its OEM one (without rust!)

16th August 2015, 22:07	#1
AndyEll Regular poster MG ZT-T Join Date: Jul 2015 Location: Bangor Posts: 44 Thanks: 1 Thanked 5 Times in 4 Posts	boomy exhaust So from time to time I get a boomy noise from the exhaust. Sounds like its hitting off the bottom of the car somewhere but when I jacked it up and gave it a good shake it didnt seem to be hitting anything. It sounds like its resonating at certain rpm. Also the back box outer case is rusted through,not a huge amount,just the size of a coke can missing below the tailpipes. Any input welcome.

17th August 2015, 09:03	#2
KWIL Precise Rover 75 Tourer 2.5KV6 Connoisseur SE Join Date: Mar 2013 Location: Fleet Posts: 2,956 Thanks: 630 Thanked 617 Times in 480 Posts	Back boxes are also called resonators and yours is because its characteristics have been changed by the "rust holes". If only the outer case has gone this should not cause much of a problem, look around the input pipe area as well. Changing it for a non MGR one will/may also give you strange noises!

17th August 2015, 09:14	#3
ProfDave This is my second home ZTT, Contemp Saloon, Duotone Tourer Join Date: May 2012 Location: Llandeilo Posts: 4,192 Thanks: 290 Thanked 387 Times in 333 Posts	If when you are driving its hitting the car worth checking your lower engine mount condition; agree with the other comments; I went for stainless replacement on two cars which car a nice note but are louder. The quietest by far is the saloon which is still on its OEM one (without rust!)