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Discussion Starter #1
Still getting used to my S5 and I've noticed a rattle, like an electronic rattle at 1200rpm, either on a very light throttle or when the revs come down to idle.

Is this normal? Is it the idle motor or something?
 

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Dave, mine does the exact same thing.
With the windows up I can't hear it but with windows down I can, and even more so if I'm next to a building or cars so the sound is bounced back more.
It is more apparent when slowing to a stop it say creeping round a carpark.
Im pretty sure mine is exhaust related, maybe even a heat shield.
When I was in for an mot I asked the mechanic to have a poke around and he thought it might be the cats rattling.
I've yet to get to the bottom of it but mine is slowly getting worse and it is quite annoying especially as I'm sure other people must be able to hear it when I'm driving slow, say through a town centre.
Maybe a full exhaust system is on the cards. 馃槵
 

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Discussion Starter #3
Hi SmokeyJoe :)

It's defo some electronic motor type device and not metallic like a shield or the exhaust - but if you want to use that as an excuse to get a new zorst, then go for it. :D

It's like a baby's plastic rattle or a rattle snake. I only noticed it creeping down the drive then coming off the throttle, as it goes past 1200rpm it does it.
 

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It is a kind of baby rattle noise on mine, I'm not 100percent if it's the exhaust or not. I can feel a slight shuddering as the car gets down to about 1200rpm and I get this noise at the same time. Then it goes quiet again below 1200. It's very annoying now the weather has improved and I'm driving around with the windows down more often. Maybe I should swap the exhaust and if it's not that hopefully it will drown the rattle out anyway lol.
 

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Sorry guys, I have no ideas. I haven't noticed anything like that on mine, and I am rather paranoid about unexpected noises.
 

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Discussion Starter #6
It does it even stationary on mine. with the driver's door open and when it has stopped beeping at you to turn ignition off, raise revs to about 1500rpm and let hem fall back down and when it passes 1200rpm it rattles.

It's definitely something like a modulation motor, it's too 'light and plasticy' to be anything mechanical. I hope. :)
 

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Does it on mine stationary too. Doesn't have to be in gear and exactly 1200rpm.
I'm pretty sure it's exhaust related on mine but really need it up on a lift to have a good poke around, seems to be more obvious when hot. I'll suss it one day hopefully because I hate rattles.
 

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So I finally discovered what the rattle is. I got someone to hold the car at 1200rpm while jacked up and I could see the left hand downpipe vibrating and rattling the cats little head off.
After some more research I found it's quite a common fault for the flexi pipe to get weak and cause the downpipe to vibrate.
I'm now booked in to my indie to have some complete new downpipes made up in stainless and to leave the cats out!
Will let you guys know how it sounds/performs in a couple of weeks.
 

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So I finally discovered what the rattle is. I got someone to hold the car at 1200rpm while jacked up and I could see the left hand downpipe vibrating and rattling the cats little head off.
After some more research I found it's quite a common fault for the flexi pipe to get weak and cause the downpipe to vibrate.
I'm now booked in to my indie to have some complete new downpipes made up in stainless and to leave the cats out!
Will let you guys know how it sounds/performs in a couple of weeks.
Funny enough i was going to create a new post about it as i got the same thing also, it doesnt make an awful sound, but i do get quite a bit of vibration on the magic 1200rpm and it is really annoying :mad:
 

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Discussion Starter #11
So I finally discovered what the rattle is. I got someone to hold the car at 1200rpm while jacked up and I could see the left hand downpipe vibrating and rattling the cats little head off.
After some more research I found it's quite a common fault for the flexi pipe to get weak and cause the downpipe to vibrate.
I'm now booked in to my indie to have some complete new downpipes made up in stainless and to leave the cats out!
Will let you guys know how it sounds/performs in a couple of weeks.
Mine has gone, cost me about 拢15 in exhaust header wrap :) It was the chain mail around the flexi section. I've only seen the woven mesh on flexi pipes, not this metal netting. When I banged on the down pipes they gave the same fizzy like rattle. Like I said, it sounded more plasticy, than a full metal rattle.

Anyway wrapped the exhaust from the Cat flange down to the first small silencer/resonator. I also put a jubilee clip around the flexi section. A little bonus to this, is the ricey rasp has pretty much disappeared when accelerating.

Are you sure they are replacing the cats!? This would mean new manifold headers. The cats are tucked up the side of the engine/gearbox. They are not the little silencers you can see underneath. :)

Also if they are actually removing the cats, you will need another remap as it will put the MIL light on due to implausible signal from the Lambda sensor.
 

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Hi Dave,

Yes sorry if I'm confusing anyone.

I am talking about the same as you, the small silencers at the bottom of the downpipes.
I've heard them called resonators, silencers and also secondary cats.

Not the primary cats right up at the header pipes.

I've seen what you mean about the chain mail flexi and apparently these things break completely sometimes.

I'm having these pipes remade with new braided flexis and straight pipes to the centre resonator where the X pipe fits.

The actual silencers/resonators/secondary cats on mine rattle when you bash them anyway so that's my excuse for leaving them out. 馃榿

It's booked in for next Monday so will report in afterwards.
 

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Discussion Starter #13
Are you having an X pipe too? :)

Keep meaning to do some sound clips/video of mine.
 

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Not at this stage, I want to see what it's going to sound like with the new downpipes first. I've told my indie that I'm concerned about drone and he reckons it probably won't sound much different from stock, maybe a bit of a deeper tone.
We shall see!
 

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Discussion Starter #15
Drone comes from back boxes essentially. You can make the exhaust slightly louder by removing the centre resonator, but the back boxes have baffles and helmholtz resonator tubes to cut the drone.

TBH, I can't see much if any difference with removing those little front silencers. Reading through other forums, removing those little silencers can increase rasp. That's where I got the idea of the wrap as someone wrapped their down pipes.

My centre section is hanging on the garage wall. :)
 

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Smokey if you remove the 2 front resonators on your downpipes it should make little or no noise difference,however it should improve the flow of your exhaust gases.
I was one of the 1st people on here to buy an x pipe and for those who want a bit more noise it is the cheapest way to go.
My miltek has no resonators in the downpipes and with the increased diameter & the miltek x pipe it sounds as good as it gets.
Imho I would remove the resonators 1st then see how it sounds the take it from there.
Interestingly enough the lad who bought my x pipe loves it ,but the baffles went in 1 of his back boxes. He replaced it with a cobra half system and says now it sounds like a Lamborghini lol.
 

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Hi Ade, thanks mate yeah my indie told me it probably won't make much sound difference also.
Ultimately the only reason I'm having these pipes replaced is to stop the awful rattling which has been getting progressively worse over the last year to the point where it's embarrassing and you might think a battered old Peugeot is coming up behind you.
The X pipe will be the next thing if I decide to go for more noise afterwards.
 

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Discussion Starter #18
Get an X-Pipe and some wrap, or just put a jubilee camp around the flexi section :)

Whilst you are getting your downpipes replaced, ask them to knock up an X-pipe - will be cheaper than the ECS x-pipe :) Could even get them to put the X where the little downpipe silencers are, this will give a more beneficial exhaust gas swop over point. The ECS X pipe is good, but too far towards the rear of the system to give max benefit.
 

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Discussion Starter #19
Smokey if you remove the 2 front resonators on your downpipes it should make little or no noise difference,however it should improve the flow of your exhaust gases.
I was one of the 1st people on here to buy an x pipe and for those who want a bit more noise it is the cheapest way to go.
My miltek has no resonators in the downpipes and with the increased diameter & the miltek x pipe it sounds as good as it gets.
Imho I would remove the resonators 1st then see how it sounds the take it from there.
Interestingly enough the lad who bought my x pipe loves it ,but the baffles went in 1 of his back boxes. He replaced it with a cobra half system and says now it sounds like a Lamborghini lol.
V6 Lambo :)
With my downpipes wrapped, it reduces the rasp to allow the thrum and howl sound to be heard. :)

Also put a pair of BMW exhaust sound dampeners just near the back boxes - not sure how much difference these make - should take them off and see.
 

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Update!
OK, got my car back Tuesday evening, the annoying rattle at 1200rpm has completely gone which is brilliant.
One of the old flexi pipes had gotten really weak and the resonator itself rattles if you shake It so if you have this rattle this is the problem.

As for the sound......it is loud! Really loud! I could not believe what removing those little resonators would do.
Good bits- cold start, gear change farts, no drone, still as quiet as stock on light throttle.
With windows up sounds great throughout the rev range.
Bad bits-with windows down sounds obnoxiously loud between 2.5-3.5k revs, at anything over perhaps a third throttle. (Sounds good with a light throttle in that zone).
Don't think I'll dare to try the x-pipe now as I think it could make it ridiculously loud but If I find a cheap one to play with in the future who knows. 馃
 
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