Sudden deep booming noise on acceleration - my imagination?
Discussion
Been out for a long drive today and for the last hour or so the car sounds noisier on hard acceleration, over say 4k revs. It's a deep booming noise, and is definitely coming from the back of the car but standing outside and revving the car, it sounds the same.
On cruising it sounds the same, and sticking my head under the car while someone pushed the throttle showed no signs of noises coming out around the back box.
There seemed to be no loss in power nor any wierd behaviour from the engine, but in any other car I would say that a big hole has opened up in the exhaust, but then you would hear it farting under the car, which this does not.
Can it be drivetrain related? Has a bush or a UJ just failed?
On cruising it sounds the same, and sticking my head under the car while someone pushed the throttle showed no signs of noises coming out around the back box.
There seemed to be no loss in power nor any wierd behaviour from the engine, but in any other car I would say that a big hole has opened up in the exhaust, but then you would hear it farting under the car, which this does not.
Can it be drivetrain related? Has a bush or a UJ just failed?
Look through the front wheel arches and check the manifolds arn't touching the top chassis rails, usually a sign the engine mountings are worn, a booming noise, hmm I'd say start by checking you haven't blown an exhaust manifold gasket, often a popping sound, you may feel warm air omitting from the failed area on a cold start up, soon as it's hot stay well away 
It's worrying me a little as it is a sudden increase in the volume of the exhaust sound, coming from behind me.
It just sounds about 20-30% louder while I'm siting in the car when we hit about 4k to the readline. Like those switches in Porsches that move a flap and all of a sudden the car is louder. A booming noise, not a louder roar, like the noise a sleeved exhaust makes.
Engine mounts were replaced earlier this year, as were the exhaust manifold gaskets.
My car is on a green tune, is decatted and is running the tvr version of the software and as this is a little richer than normal I noticed when I switched it on for the first time a few months ago that the car seemed louder back then.
I have an act y piece, am fully decatted but have a standard exhaust muffler.
Just thinking that surely, if it was exhaust related and had a failure inside the box would it make it louder?
At tickover I am not sure but it sounds the same as normal
It just sounds about 20-30% louder while I'm siting in the car when we hit about 4k to the readline. Like those switches in Porsches that move a flap and all of a sudden the car is louder. A booming noise, not a louder roar, like the noise a sleeved exhaust makes.
Engine mounts were replaced earlier this year, as were the exhaust manifold gaskets.
My car is on a green tune, is decatted and is running the tvr version of the software and as this is a little richer than normal I noticed when I switched it on for the first time a few months ago that the car seemed louder back then.
I have an act y piece, am fully decatted but have a standard exhaust muffler.
Just thinking that surely, if it was exhaust related and had a failure inside the box would it make it louder?
At tickover I am not sure but it sounds the same as normal
ClassiChimi said:
If one of the perforated pipes becomes detached then you could be getting gases escaping past and so causing the boom, drone.
Might be that then. I'll get it to my exhaust fabricator and put it on a ramp and hopefully we can hear the box making booming droning noises.
I'd start by dropping the pipe and shaking it, it's full of wadding so no guarantee it will rattle, probably the only way to know will be to cut it open! Are your pre cats removed too.
If it does need opening up you could also sleeve the box, another can of worms, some say it's to loud, others it's like a tractor, I was at Donnington earlier this year watching a huge 60's yank motor shaking down, that had straight through pipes, sounded like my Tvr
Mines fully sleeved, I'd go half sleeved if doing it again.
If it does need opening up you could also sleeve the box, another can of worms, some say it's to loud, others it's like a tractor, I was at Donnington earlier this year watching a huge 60's yank motor shaking down, that had straight through pipes, sounded like my Tvr
Mines fully sleeved, I'd go half sleeved if doing it again.
When I bought the car it had an Offord Sports exhaust - which was basically a twin cherry bomb in a barrelled silencer.
Sounded like the red arrows flying over everytime I pulled away from the lights. The quieter OEM silencer, combined with the ACT Ypiece and decat is more than loud enough but it can be driven stealthily around town too.
Sounded like the red arrows flying over everytime I pulled away from the lights. The quieter OEM silencer, combined with the ACT Ypiece and decat is more than loud enough but it can be driven stealthily around town too.
jazzdude said:
Anyone have a standard exhaust box fail internally before, can that make more noise? There is not any sign of anything leaking in the pipework either side of it.
I had this happen. Car started failing track day noise tests. Changed the entire exhaust pipe (from behind the Y). Problem solved.
As soon as I read your post I thought "exhaust resonating".
Edited by QBee on Saturday 5th November 02:37
QBee said:
I had this happen. Car started failing track day noise tests.
Changed the entire exhaust pipe (from behind the Y). Problem solved.
As soon as I read your post I thought "exhaust resonating".
As the 'entire exhaust' other than the silencer is a pipe I guess I need to get a new silencer. Changed the entire exhaust pipe (from behind the Y). Problem solved.
As soon as I read your post I thought "exhaust resonating".
Are they only sold complete with the pipework?
jazzdude said:
QBee said:
I had this happen. Car started failing track day noise tests.
Changed the entire exhaust pipe (from behind the Y). Problem solved.
As soon as I read your post I thought "exhaust resonating".
As the 'entire exhaust' other than the silencer is a pipe I guess I need to get a new silencer. Changed the entire exhaust pipe (from behind the Y). Problem solved.
As soon as I read your post I thought "exhaust resonating".
Are they only sold complete with the pipework?
can't post pics as Photobucket is under maintenance. The Chim silencer below , is just 2 perforated tubes surrounded by wanding, take it off and check the welds have not given way, you will have to cut an inspection hole to look inside and should be an easy repair, as you will see when you have it off and see if anything is broken inside, obviously check that none of the welds are cracked on the exterior where the tube goes into the silencer?
https://www.google.com/search?q=tvr+chimaera+silen...
Edited by portzi on Saturday 5th November 06:35
Edited by portzi on Saturday 5th November 06:37
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