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Discussion Starter #1
I had a powerflow cat-back system which sounded like it was failing....i was getting vibrations through the car, the noise was droning and didnt change pitch as i moved up and down the gears...i took it to an exhaust specialist and he said it was in ok condition, no holes just getting on a bit with a few dints on it (it was 2nd hand off a breaker) and was quoted 658 lifetime guarantee stainless steel in the process. Now if the car is new, ok go ahead.

It couldn't really be anything else, the tyres were changed last July on the teledials and there is a bit of inbalance but not much....so i bought a new cybox system, fitted it last night and the symptons are virtually the same!

Droning, vibrations, exhaust note fairly unchanged, i am pretty gutted. Where to start resolving this?

I am now not convinced its the exhaust at all. I am thinking engine mounts, knackered cat, driveshafts etc

Any help appreciated
 

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Bang gently on the exhaust with a hammer. I used this method to find what caused my vibration sound.

Turned out to be the part going trough the exhaust-rubber.. It was to long, and was rubbing on the chassie. (CSC mid exhaust)
 

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Was the exhaust heat shield checked? These can wear out and rattle, similar to your description.

Also, play in front pipe flexi will make similar noise; had that issue on my old Saab 9-3.

Suspension will be knocking and clunking over pot holes etc.
 

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Bang gently on the exhaust with a hammer. I used this method to find what caused my vibration sound.
Make sure it's a rubber hammer ;)

Also the rubber mounts can perish for the exhaust hangers. So the whole thing could be a bit wobbly.
 

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Discussion Starter #5
Make sure it's a rubber hammer ;)

Also the rubber mounts can perish for the exhaust hangers. So the whole thing could be a bit wobbly.
My first point of call will be the mid exhaust clearance around the heat shield , I am sure there is an issue there. The issue going into 3rd gear at 30mph which is shaking the car is my biggest concern, gets worse as you accelerate , feels slightly down in power and 3rd 4th and 5th gear have no change of exhaust note is also a problem
 

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Take the powerflow off and throw it away! I made the mistake of getting a system done by them (on a different make of car) and despite the assurance of a lifetime guarantee within 2 years the pipework had corroded so badly it snapped in half. Luckily I was on my way to Janspeed to have a properly designed system fitted (that was 12 years ago and the Janspeed system is still as good as the day it was fitted). The problem is that Powerflow is a franchise so you are at the mercy of the monkey that made it plus the parts used are generic parts so no guarantee that they will make any difference to the performance and more likely due to the changes will probably affect exhaust gas flow which in turn can affect scavenging and subsequent loss of power.
 

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Discussion Starter #7
Was the exhaust heat shield checked? These can wear out and rattle, similar to your description.

Also, play in front pipe flexi will make similar noise; had that issue on my old Saab 9-3.

Suspension will be knocking and clunking over pot holes etc.
Under the car this morning at 7.00am! 1st Heat shield along the straight tunnel was catching and is failing around the nut, the second heatshield had been bent over, same!

Checking the driveshaft nuts later as the vibration is still there and now clicking not knocking. The wife says its my hobby.....as i am doing 100 miles tomorrow more of a necessity!

Thanks for the tips guys
 

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Does the droning change with speed but not rev's? My wheel bearing were on the way out last year and this is what they sounded like when the problem first started. I blamed the exhaust too!
 

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Have you checked the manifold... they are known to crack on the TS.

CAT could be knackered.

Check the joints on the 2-to-1 section as well.

Heat shied, exhaust rubbers, etc etc.

Sad to say it, but I think the first guy has sold you a bit of a turkey in telling you to replace the whole system :(
 

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Use some extra large washers to fix the heat shields. That happened to me last summer, it does make quite a racket when it's loose. So if 2 are rattling that will be loud.
 

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Discussion Starter #12
Does the droning change with speed but not rev's? My wheel bearing were on the way out last year and this is what they sounded like when the problem first started. I blamed the exhaust too!
I think you have got it here....sounds like a failed wheel bearing(s) when I turn the car quickly to the right the weight gets pushed over and the sound temporarily goes quiet...so I am thinking logically a fail on the passenger side. Anyone know how I can test back or front?
 

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The best way to test wheel bearings is to jack up the car, spin up the wheels and listen. This can be a pain on the front with the driveshaft, etc slowing things down. Obviously you should also check for any free play first, but modern wheel bearings don't tend to go loose first, just noisy.
 
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