Resonance from cat

Dave Goody · 25th July 2007, 21:56

I had a new cat fitted end of last year. I must admit, the cheapest I could find. I get a "Wahh" from this at about 2,200 RPM, only lasts a split second when accelerating hard but when cruising slowly in higher gears it keeps appearing at this RPM. Any suggestions for curing? It must be a resonance caused by thinner metal than the original? I thought maybe wrap a silencer bandage around it? Can anyone come up with a neater suggestion?

Dave

JohnDotCom · 25th July 2007, 23:09

Now if it was a Diesel I'd say By Pass it.
Surely still under warranty take it back Dave.

Dave Goody · 25th July 2007, 23:19

Quote:

Originally Posted by JohnDotCom

Now if it was a Diesel I'd say By Pass it.
Surely still under warranty take it back Dave.

Hi John, its a unipart one and the 1st proved faulty but also made same noise, I had it replaced and the new one makes same noise so guess all do this. I will only be able to change for much more expensive one so am looking for a cheap fix. I dont mind spending money on mechanical replacements but I regard a cat as a non important nescessity for passing mot!
Do you think a couple of huge jubilee clips might work?
Dave

JohnDotCom · 25th July 2007, 23:23

You could try that, it sounds as if something inside is causing noise like a loose baffle if it was a silencer, Should work regardless of what you pay really IMHO.

Dave Goody · 25th July 2007, 23:39

Quote:

Originally Posted by JohnDotCom

You could try that, it sounds as if something inside is causing noise like a loose baffle if it was a silencer, Should work regardless of what you pay really IMHO.

I agree John, but as 2 have sounded exactly the same I would guess it is a resonance from the body [outer skin], the cat works, just makes a little more noise, in fact some people have said it sounds nice. I think the only way would be to return and pay £100 more for a better cat. For £100 I can live with it but there may be a cheap fix? Dave

JohnDotCom · 25th July 2007, 23:42

Well try the huge clips or even Exhaust bandage to see if that helps.
(do that still make that?)

Dave Goody · 26th July 2007, 00:15

Quote:

Originally Posted by JohnDotCom

Well try the huge clips or even Exhaust bandage to see if that helps.
(do that still make that?)

I can remember buying the exhaust bandage when a cash strapped 18 year old, God knows if you can still buy these? I will try the jubilee clips 1st!
Dave

Tim_Burgess · 28th July 2007, 14:06

This is interesting... My 1.6 K series Tomcat had to have new cat for the MOT this year and it does exactly the same thing.

The work was done by my local MGR specialist using either genuine Rover or Unipart Cat, not sure which. i'm hoping when I've done a few miles ant its got a bit sooty the nois will go away.

T-Cut · 28th July 2007, 17:04

Quote:

Originally Posted by Dave Goody

I can remember buying the exhaust bandage when a cash strapped 18 year old, God knows if you can still buy these?

You sure can, I bought a pack quite recently. Only problem is, you get a measely 18 inches and a foot of flimsy copper wire. About enough for a dodgy lawnmower. I doubt you'd get any sound deadening from it anyway.

How about wrapping the cat in an inch of fireproof fibreglass matting or loft insulation? Jacket that in thin sheet aluminium and hold it all together with jubilee clips?

TC

25th July 2007, 21:56	#1
Dave Goody This is my second home 15 years of 75s & ZTs now an XTrail Join Date: Nov 2006 Location: Danbury, Essex Posts: 3,761 Thanks: 18 Thanked 88 Times in 56 Posts	Resonance from cat I had a new cat fitted end of last year. I must admit, the cheapest I could find. I get a "Wahh" from this at about 2,200 RPM, only lasts a split second when accelerating hard but when cruising slowly in higher gears it keeps appearing at this RPM. Any suggestions for curing? It must be a resonance caused by thinner metal than the original? I thought maybe wrap a silencer bandage around it? Can anyone come up with a neater suggestion? Dave __________________ ZT 190 X Power Grey The Only Colour is this Dark Silver!! When I was a kid I was scared of earwigs because I thought they actually lived in your ears. I was even more terrified of cockroaches!

28th July 2007, 14:06	#8
Tim_Burgess This is my second home 1999 75 Connoisseur SE 2.5, 2000 75 Classic SE 2.0, 2012 Lancia Delta 3, 2016 Dacia Sandero Ambiance Join Date: Jan 2007 Location: Kilcreggan Posts: 3,191 Thanks: 334 Thanked 334 Times in 162 Posts	This is interesting... My 1.6 K series Tomcat had to have new cat for the MOT this year and it does exactly the same thing. The work was done by my local MGR specialist using either genuine Rover or Unipart Cat, not sure which. i'm hoping when I've done a few miles ant its got a bit sooty the nois will go away. __________________ *The fact there's a highway to hell and only a stairway to heaven says a lot about anticipated traffic numbers.*.

25th July 2007, 23:09	#2
JohnDotCom * Rover 75 FaceLift Tourer CDTi 170BHP Auto ConnSE 2005 Model Starlight Silver Join Date: Nov 2006 Location: Abergele Posts: 28,735 Thanks: 0 Thanked 6 Times in 5 Posts	Now if it was a Diesel I'd say By Pass it. Surely still under warranty take it back Dave.

25th July 2007, 23:23	#4
JohnDotCom * Rover 75 FaceLift Tourer CDTi 170BHP Auto ConnSE 2005 Model Starlight Silver Join Date: Nov 2006 Location: Abergele Posts: 28,735 Thanks: 0 Thanked 6 Times in 5 Posts	You could try that, it sounds as if something inside is causing noise like a loose baffle if it was a silencer, Should work regardless of what you pay really IMHO.

25th July 2007, 23:42	#6
JohnDotCom * Rover 75 FaceLift Tourer CDTi 170BHP Auto ConnSE 2005 Model Starlight Silver Join Date: Nov 2006 Location: Abergele Posts: 28,735 Thanks: 0 Thanked 6 Times in 5 Posts	Well try the huge clips or even Exhaust bandage to see if that helps. (do that still make that?)